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2021 Fall Meeting

Nanoparticles and nanomaterials


Nanomaterials- electronics & -photonics

This symposium will cover:

(i) Nanomaterials Synthesis: From 0D, 1D, 2D, and 3D, Multifunctional Hybrids.

(ii) Investigations: Structures and Properties, Analytical and Computational Modeling.

(iii) Applications: (a) Electronics- Gas/Pressure/Chemical/Biological Nanosensing, (b) Photonics/Plasmonics/Photovoltaics/Lighting Technologies, (c) Energy/Piezotronics/Green Energy (e) Photocatalysis, Water Purification, (f) Biomedical Nanomaterials, (g) Advanced technologies.


Nanostructures, particularly from inorganic metal oxides, organic, carbon, polymers, etc. family, are very important material candidates because of their surface-to-volume and morphology-dependent extraordinary properties suitable for various advanced technologies. The ongoing deployments in the direction of 0D (quantum dots), 1D (hybrid nanowires), 2D (from new semiconductors) and 3D networked materials have further become very relevant towards various applications, due to their excellent nanoscale features and simplicity of utilization. Due to their compact synthesis forms, they can be easily handled or integrated in the desired manner in devices or sensors. The 0D, 1D, 2D nanostructures from noble metals (Au, Ag, Cu, etc.) have found immense applications in sensing, biomedical, waveguides and telecommunications, etc. Nanostructures from metal oxides have been very interesting (fundamental as well applied) materials due to interesting bandgap values (intermediate between metals and insulators), suitable for various advanced technologies. When these metal oxides and metals are combined together in hybrid nanomaterials, they become further very relevant in terms of understanding the properties and accordingly applications. The carbon nanostructure family, i.e., fullerenes, CNTs (MWCNTs), graphene, graphene oxide (GO), etc., have shown very strong potential ranging from fundamental properties to advanced energy applications and hence have been the subject of huge research attention in the last couple of decades. Recent developments in the direction of 3D carbon networks have opened an entirely new dimension in nanotechnology research. Research on 3D soft ceramics from metal oxides interconnected networks, which is currently in the mainstream research focus, is very important, because it can be very helpful in up scaling the nanotechnology-related applications in modern life.

Appropriate growth strategies of different structures (0D, 1D, 2D and 3D) using simple methods, understanding their properties, their applications in different directions, etc. are still key issues. Interdisciplinary research platforms are required, which are equipped with: (i) synthesis groups for developing different nanostructures, (ii) theoretical/computational scientists, who can analyze/simulate for understanding the structure-property relations, and (iii) application experts, who can accordingly utilize these materials in various applications, which will be actually the main aim of the proposed symposium.

Hot topics to be covered by the symposium:

  • Hybrid Metal Oxide Materials (0D, 1D, 2D, 3D): Synthesis & Characterizations, Structure-property relations, Analytical/Simulation studies, Applications: Electronics-Chemistry-Energy-Sesning-Lightening-Biomedical-Environmenta - Applications,
  • Plasmonic Nanostructures: Synthesis & Characterization, Computational Modeling, Sensing and Nanophotonics Applications
  • Carbon Family (Fullerenes to 3D graphene): Fabrication & Characterizations, Structure-property relations, Simulations studies, Applications: Nanoelectronics-Sensing-Supercapacitor-Batteries-Energy.
  • Quantum Dots: QDs are recently gaining huge interests and one session of the symposium will be devoted to only QDs.
  • Perovskites: QDs, NCs, nanowires, thin films, synthesis and applications.
  • Synchrotron radiation/Ion beam-based material characterization and engineering

List of invited speakers:

  • Alexander Urban, LMU Munich, Germany
  • Angshuman Nag, IISER Pune, India
  • Julia Pérez-Prieto, University of Valencia, Spain
  • Hannah Kerr, RSC Publishers, UK
  • Andreas Seifert, CIC nanoGUNE, San Sebastian, Spain
  • Søren Peder Madsen, Aarhus University, DK
  • Joana Rodrigues, University of Aveiro, Portugal
  • Santanu Ghosh, IIT Delhi, India
  • Thierry Baron, CNRS Gronable, France
  • Barbara Fazio, CNR, Italy
  • Daniel A. Heller, Cornell University, USA
  • Anna Pellegrino, University of Catania, Italy
  • Shiraki Tomohiro, Kyushu University, Japan
  • Juan Jose Vilatela, IMDEA, Spain
  • Ioannis Papakonstantinou, UCL London, UK
  • Marc Zastrow, Wiley VCH, Germany
  • James Neilson, Colorado State University, USA
  • Elke Debroye, KU Leuven, Belgium
  • Maria Censabella, University of Catania, Italy
  • Emersen Coy, Adam Mickiewicz University, Poland


E-MRS Fall 2021: Special Issue in Wiley VCH Journal -Physica Status Solidi (A):

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Welcome address and Session 01- Nanomaterials Growth & Applications : Y. K. Mishra, D. Janas, R. Puglisi
Authors : J. Rodrigues1,*, S. O. Pereira1, J. Zanoni1, C. Rodrigues1, M. Brás1, J. P. Moura1, N. F. Santos1, A. F. Carvalho1,2, B. P. Falcão1,2, J. P. Leitão1, A. J. S. Fernandes1, L. Rino1, T. Monteiro1, F. M. Costa1
Affiliations : 1i3N, Department of Physics, University of Aveiro, 3810-193 Aveiro, Portugal. 2CICECO, Department of Physics, University of Aveiro, 3810-193 Aveiro, Portugal.

Resume : Zinc oxide (ZnO) has been receiving increasing attention as a promising platform for biosensing applications. In the present work, we explore the potentialities of ZnO nanostructures grown by laser-assisted flow deposition (LAFD) [1] to be incorporated as a transducer element in optical biosensors, aiming at the detection of relevant biomarkers for health and environment applications. The focus is put on the detection via photoluminescence (PL) spectroscopy, a powerful technique to assess and evaluate biointerfaces between the transducer and analytes that has not been widely explored in the sensing field. Two case studies, dedicated to the detection of (i) human chorionic gonadotropin (hCG) hormone [2] and (ii) tetracycline, will be presented. In both cases, changes in the PL output of the ZnO transducer are observed, particularly a decrease of the overall intensity with increasing analyte concentrations. Control samples prepared without the bioreceptor element exhibit no significant PL changes, confirming that the signal variation observed in the former cases are due to biorecognition events. Hence, it is demonstrated that these ZnO transducers can provide a sensing platform that allows the tuning of the target analyte by selecting the appropriate biorecognition element. Finally, the importance of choosing an adequate buffer solution to conduct the sensing experiments is also discussed, as it is found that phosphate-based buffers promote a partial or even fully conversion of ZnO into zinc phosphate, resulting in changes in the transduction signal that are not directly related to biorecognition events and, consequently, may mislead the interpretation of the sensing outcome. [1] J. Rodrigues, et. al., CrystEngComm. 21 (2019) 1071?1090. [2] J. Rodrigues, et. al., Appl. Surf. Sci. 527 (2020) 146813.

Authors : N. Amara, A. Martin, A. Potdevin*, D. Riassetto, G. Chadeyron, M. Langlet
Affiliations : N. Amara, A. Martin, D. Riassetto, M. Langlet: Univ. Grenoble Alpes, CNRS, LMGP, 3 parvis Louis Néel, 38016 Grenoble, France N. Amara, A. Martin, A. Potdevin,G. Chadeyron: Université Clermont Auvergne, CNRS, Clermont Auvergne INP, Institut de Chimie de Clermont-Ferrand (ICCF), 63000 Clermont-Ferrand, France

Resume : The main objective of this work is to take advantage of the specificities of Zinc Oxide (ZnO) Nanowires (NWs) array (porosity, specific surface?) for LED lighting. The ZnO NWs were grown by hydrothermal synthesis from a ZnO seed layer directly deposited on the sol-gel derived Ce-doped yttrium aluminum garnet (YAG :Ce) coatings. Highly dense array of vertical ZnO NWs was evidenced on the top of YAG:Ce coating by optical and electron microscopy. The use of NWs plenary arrays was expected to influence heterostructure features, notably their optical properties. XRD, SEM and angle-dependent photoluminescence measurements have been carried out to study the structural, morphological and optical properties of these functional coatings. In particular, the optical study showed that this original design leads to a different angular distribution of light together with an increase in emission efficiency of YAG:Ce coating upon blue excitation compared to the flat coating (up to *1.7). These improvements will be discussed in reliance on multiscattering events for photons within the structure, allowing them to escape the phosphor layer by taking optical paths different from those of the flat coating.

Authors : Bruno, L.(1,2), Strano, V.(1,2), Franzò, G.(2), Priolo, F.(1,2), Mirabella, S.(1,2)
Affiliations : (1) Dipartimento di Fisica e Astronomia ?Ettore Majorana?, Università di Catania, via S. Sofia 64, 95123 Catania, Italy; (2) CNR-IMM, via S. Sofia 64, 95123 Catania, Italy.

Resume : The mechanism of radiative recombination and emission of ZnO nanorods and the effect of Au nanoparticle (20 nm in size) decoration on the luminescence properties are studied. ZnO nanorods (100 nm wide, 700 nm long) were synthesized by chemical bath deposition while decoration with small Au nanoparticles (density of 10^10 nanoparticles/cm^2) was achieved by immersing the sample in a colloidal solution of nanoparticles. The decoration of this metal oxide with noble metal nanoparticles has been quantitatively investigated by Scanning Electron Microscopy and Rutherford Backscattering Spectrometry, while the emission properties of the bare and decorated samples have been studied by photo- and cathodo-luminescence. Radiative recombination mechanism has been studied through depth-resolved cathodoluminescence analyses (supported by Montecarlo simulations), while generation, diffusion, and recombination of electron-hole pairs below the surface has been deeply investigated and simulated. The combination of ZnO nanorods and Au nanoparticles causes a significant depletion of free electrons below the surface, leading to a reduction of UV emission and an increase of visible-UV intensity ratio. The formation of a nano-Schottky (modelled with a multiphysics approach) leads to a relevant bending of ZnO energy bands, evidencing a strong electric field beneath the metal-semiconductor interface which affects the emission [1]. The depletion of free carriers in decorated ZnO nanorods allows the application of these composite materials in UV sensing and light induced catalysis. [1] Bruno L., Strano V., Franzò G., Priolo F., Mirabella S., Photoluminescence investigation of electronic band bending in ZnO nanorods induced by Au nanoparticle decoration (submitted to Applied Physics Letters AIP).

Authors : Reza Abolhassani, Fateme Sadat Mirsafi, Horst-Gunter Rubahn, Yogendra Kumar Mishra
Affiliations : Mads Clausen Institute, NanoSYD, University of Southern Denmark Alsion 2, 6400, Sønderborg, Denmark

Resume : Nanoscale materials with multifunctional properties have received increasing interest in scientific and industrial communities because of their versatile applications in advanced technologies. Porous materials are of scientific and technological interest because they are capable to interact with atoms, ions, and molecules both on their surfaces and throughout the bulk of the material. Therefore, there is a broad range of applications for porous materials such as catalysis, sensors, fuel cells, capacitors and batteries, filters, and biomedical applications. ZnO tetrapod is a 3D-shaped nanostructure built out of four ZnO nanorods, hence offers 1D nanorod-shaped features too. In this work, ZnO tetrapods will be synthesized using the simple and one-step approach, called Flame Transport Synthesis (FTS). The arm morphologies in the complex shaped structures will be tailored by changing growth parameters. The obtained loose ZnO tetrapod powder is then compressed in molds with various geometrical shapes and well-defined volumes, and then heated at high temperatures to construct highly porous 3D interconnected networks. Later, these networks with porosities up to 98% can be used as sacrificial templates to grow hollow tetrapodal 3D framework networks from other materials. In this manner, the desired materials (metals, metal oxides, nitrides, carbon, etc.) will be coated on the 3D interconnected ZnO network, and beneath ZnO will be etched away. As a result, a highly porous 3D network of the desired material in microscopic tetrapodal shape will be obtained which is not possible to fabricate by any other method.

Authors : Reza Abolhassani, Fateme Sadat Mirsafi, Horst-Gunter Rubahn, Yogendra Kumar Mishra
Affiliations : Mads Clausen Institute, NanoSYD, University of Southern Denmark Alsion 2, 6400, Sønderborg, Denmark

Resume : Technological development and industrialization have dramatically increased energy consumption in the past decades, and energy demand is expected to increase by three times by 2050. At the same time, pollution is going to be a great concern. One requires renewable energy technologies which also take care of the environment. Metal oxides nanomaterials in hybrid functional form have shown promising potentials as catalysts, however, nanomaterials design plays a very important role. In this work, we present a unique three-dimensional design of nanomaterials with huge catalytic potential. Using a combined flame and wet chemical approach, a copper oxide-zinc oxide tetrapodal 3D network material with high porosity was synthesized and characterized in detail towards its structure-property relationships. These CuO-ZnO tetrapods network showed excellent catalysis response for methylene blue degradation in water which will be briefly discussed.1 Primary investigation showed the ability of 3D nanomaterials in hydrogen evolution reaction and other catalytic applications which will be highlighted too. 1- Materials Today Chemistry, Volume 17, 2020, 100336

Authors : Joana Rodrigues (1), Charline Becker* (2), Nabiha Ben Sendrine (1), Marius Kamp (3), Lorenz Kienle (3), Rainer Adelung (3), Yogendra Kumar Mishra (4), Wolfgang J. Parak (2), Indranath Chakraborty (2), Maria Rosario Correia (1), Teresa Monteiro (1)
Affiliations : (1) Univeristy of Aveiro, Portugal; (2) Universität Hamburg, Germany; (3) Kiel University, Germany; (4) University of Southern Denmark, Denmark * lead presenter

Resume : Optical spectroscopic measurements are conducted on luminescent silver nanocluster (AgNC) decorated ZnO tetrapods (ZnO Tp), AgNC@ZnO Tp, synthesized via a colloidal route. Their properties are compared with those of the corresponding AgNC and ZnO Tp to understand their impact on the photoluminescence (PL). Raman spectroscopy reveals the high structural integrity of the ZnO structure in the AgNC@ZnO Tp. PL analysis of the ZnO Tp shows a well-resolved near band edge emission and a green band comprised by the overlapping of at least three emitting optical centres. The addition of AgNC to ZnO Tp in the hybrid material enhances the emission from ZnO surface states. The recombination of the AgNC in water solution is dominated by a red emission band peaking at ?1.9 eV and the PL excitation spectra monitored at the band maximum reveal that the red PL of AgNC is preferentially populated by well-defined excitation bands corresponding to discrete electronic transitions of the NCs. Yet, a shift to lower energies of the AgNC emission occurs in the AgNC@ZnO Tp hybrid when excited with energies below the ZnO bandgap, while for energies above this value no emission from the AgNC was observed, with the ZnO-related recombination dominating the spectra. A gradual loss in the PL intensity of the AgNC is observed in the hybrid with increasing time, which is consistent with their coalescence to transform into larger Ag nanoparticles (NPs) on the tetrapod surface, as revealed by confocal microscopy.

Authors : Gen-Wen Hsieh, Shih-Rong Ling, Fan-Ting Hung, Pei-Hsiu Kao, Jian-Bin Liu
Affiliations : Institute of Lighting and Energy Photonics, College of Photonics, National Yang Ming Chiao Tung University

Resume : Touch sensing has found immense applications ranging from mobile communication and display to various wearable devices for advanced health monitoring. Thus, there is a tremendous demand for more accurate, delicate pressure sensing elements that can be implemented into health care and medical diagnosis systems, as well as electronic skins. Future artificial robots or amputees wearing flexible pressure sensors could feel the sense of touch or the texture of the fingertip. In this regard, flexible piezocapacitive pressure sensors with high sensitivity and low limit of detection, which can function in human skin perception, fine touch, weak interaction, and gentle manipulation, are highly desired. Recently, elastomeric polymer, such as poly(dimethylsiloxane), has been regarded a promising material of choice as dielectric layer, because of its superior flexibility, elastic properties, and biomedical and human tissue compatibility. However, upon very small pressure this type of elastomer is not able to produce enough deformation; after removal of pressure the relaxation time back to initial thickness is inactive. Although several methods of introducing microstructures or micropores into the dielectric layers have been discussed, they are generally complex and expensive. Here, we demonstrate polymeric piezocapacitive pressure sensors based on a novel composite dielectric film of poly(dimethylsiloxane) elastomeric silicone with zinc oxide tetrapod. Electrical characterization results from these composite devices with an appropriate loading of tetrapods show remarkable sensing performance in capacitance change and pressure sensitivity of 2.55 kPa(−1) over that of pristine polymer sensors, enabling a minimum detectable pressure of only 1.0 Pa. Further, the operational stability, reliability and demonstration of the device for monitoring human physiological movements are also discussed. It is expected that the proposed piezocapacitive pressure sensors incorporating stress-sensitive additives of zinc oxide nanostructures may open up a promising means for potential applications in ultrasensitive touch sensing, wearable device and electronic skin.

09:55 Q&A live session    
Session 02-2D Materials: Growth & Applications : R. Puglisi, J. Adam, Y. K. Mishra
Authors : T. Baron1, H. Mehdi1, P. Hauchecorne1, P. Gaillard3, Jeremy DaFonseca3, V. Letka1, M. Martin1, J. Moeyaert1, V. Loup3, F. Bassani1, B. Salem1, M. Tang4, S. Chen4, H. Liu4, C. Jany3
Affiliations : 1. Univ. Grenoble Alpes, CNRS, CEA/Leti Minatec, LTM, F-38054 Grenoble Cedex 2 STMicroelectronics, 850 rue Jean Monnet, F-38926 Crolles Cedex, France 3 Univ. Grenoble Alpes, CEA, LETI, 38000 Grenoble, France 4 University College London, Torrington Place, London, WC1E 7JE, United Kingdom

Resume : The last twenty years have shown an impressive increase of the number of connected objects. Grouped under the generic term of Internet of Things (IoT) those connected devices are based on data acquisition, analysis, transfer and storage. To respond to these needs, an important development was done to increase the number of functionalities integrated in microelectronic chips. All those developed devices consume an important amount of energy and raw materials. The microelectronics industry is mostly based on silicon material. Nevertheless, for specific applications such as optical sensors, emitters, RF, etc. other materials are used due to better properties. This is the case for III-V semiconductors which exhibit most of the time a direct band gap and better carrier mobilities. Several routes with different Technology Readiness Level are developed to co-integrate III-V with Si in microelectronics chips. In this contribution, we will review the different technologies compatible with large-scale integration to integrate III-V semiconductors among them (i) wafer and die bonding, (ii) bonding and regrowth, (iii) direct hetero-epitaxy. We will then focus on the latest developments on direct heteroepitaxy on Si either on full wafer or in selective epitaxy. The materials considered are binaries GaAs and InP and their ternary and quaternary alloys which allow to cover a broad range of applications (emitters, photodetectors, RF?). As prospective solution, 2D materials monochalcogenides elaborated on large scale 300 mm Si substrates will be presented and photodetection capabilities will be shown. This work was supported by the French government managed by ANR , IRT Nanoelec ANR-10-IRT-05, ANR-15-IDEX-02 and LabEx Minos ANR-10-LABX-55-01

Authors : Margherita Bolognesi, Salvatore Moschetto, Marco Brucale, Gabriele Manca, Luana Persano, Mariangela Castriciano, Peter Beton, Elisa Passaglia, Maurizio Peruzzini, Stefano Toffanin
Affiliations : Margherita Bolognesi, Salvatore Moschetto, Marco Brucale,Stefano Toffanin: Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Consiglio Nazionale delle Ricerche (CNR), Via P. Gobetti 101, 40129 Bologna, Italy; Gabriele Manca,Maurizio Peruzzini: Istituto di Chimica dei Composti Organometallici (ICCOM), Consiglio Nazionale delle Ricerche (CNR), Via Madonna del Piano 10, 50019 Sesto Fiorentino, Florence, Italy; Luana Persano: Laboratorio NEST, Scuola Normale Superiore and Istituto Nanoscienze, Consiglio Nazionale delle Ricerche (CNR), Piazza San Silvestro 12, I-56127 Pisa, Italy; Mariangela Castriciano: Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Consiglio Nazionale delle Ricerche (CNR), c/o Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche e Ambientali, University of Messina, V.le F. Stagno d?Alcontres 31, 98166 Messina, Italy; Peter Beton: School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK; Elisa Passaglia: Institute for the Chemistry of OrganoMetallic Compounds (ICCOM), SS Pisa, Consiglio Nazionale delle Ricerche (CNR), Via Moruzzi 1, 56124 Pisa, Italy

Resume : Semiconducting 2D black phosphorus (2D bP) has recently attracted a lot of interest thanks to its peculiar properties, which render it suitable for applications in materials science. In particular, surface functionalized 2D bP and 2D bP heterostructures are promising for electrical, optoelectronic and photocatalytic applications.[1] Herein we report our works on the preparation, characterization and application of 2D bP functionalized with organic molecules or metallic nanoclusters, or modified by an unconventional deposition method in oxidizing conditions, and of the potential applications of such nanostructures. We first report on a non-covalent heterostructure of 2D bP with organo-boron derivatives of a conjugated fluorescent molecule.[2] Experiments and simulations showed an overall increased stability of both moieties in the heterostructure, and functionality as a fluorescent probe for molecular oxygen. We also report on the epitaxial ordering, kinetics and energetics of a Van der Waals (vdW) epitaxial system of 2D bP and tetracosane (n-alkane with 24 C atoms).[3] Electrostatic force microscopy also proved that the epitaxial nanolayers behave both as a passivating agent and as an electrical insulator (nanodielectric), setting the basis for the possible use of the heterostructure in 2D bP based metal-insulator-semiconductor (MIS) systems. A third work focuses on the use of electrospray to deposit nano-flakes of bidimensional oxidized bP with a P2O5-like crystallographic structure and a large surface area.[4] Piezoresponse Force Microscopy (PFM) demonstrated the electro-mechanical responsivity of the so obtained 2D P2O5 nano-flakes, opening towards their possible implementation for energy harvesting/conversion applications. Another work focuses on 2D bP functionalized through a ?stabilizer-free? heterogeneous reaction, leading to an optimal nanostructuring of Au. The soft-pairing/coordination of surface P and Au(I) atoms at the interface was demonstrated. This system holds promise for catalytic applications, such as electro-, photo- or photoelectro-chemical catalysis. A final work reports on the preparation and characterization of new composites based on mixtures of two immiscible polymers, namely poly (3-hexylthiophene-2,5-diyl) and poly (methyl methacrylate) (P3HT/PMMA), containing dispersed 2D-bP obtained by liquid phase exfoliation or by in situ polymerization technologies. The 2D bP nanoflakes preserved their structural and physico-chemical features, while the establishment of interactions at the interface between the 2D-bP flakes and the polymers, especially with the P3HT phase, led to a significant variation of the morphological and electrical characteristics of the composites. The authors thank the European Research Council (ERC) under the EU H2020 program for funding the project PHOSFUN by an ERC Advanced Grant to Maurizio Peruzzini (GA 670173). [1] M. Peruzzini, R. Bini, M. Bolognesi, et al.. Eur J Inorg Chem. 2019, 11-12, 1476-1494. [2] M. Bolognesi, S. Moschetto, M. Trapani, et al., ACS Appl. Mater. Interfaces 2019, 11, 25, 22637?22647. [3] M. Bolognesi, M. Brucale, A. Lorenzoni, et al., Nanoscale, 2019, 11, 17252-17261. [4] S. Moschetto, M. Bolognesi, F. Prescimone, et al., ACS Appl. Nano Mater. 2021, 4, 3476?3485.

Authors : Zouhour Ben Jabra, Isabelle Berbezier, Adrien Michon, Mathieu Koudia , Elie Assaf, Antoine Ronda, Paola Castrucci, Maurizio De Crescenzi, Holger Vach, Mathieu Abel
Affiliations : Zouhour Ben Jabra; Isabelle Berbezier; Mathieu Koudia; Elie Assaf; Antoine Ronda; Mathieu Abel; Aix Marseille University, Université de Toulon, CNRS, IM2NP Marseille, France Adrien Michon; CRHEA, Université Co?te d?Azur, CNRS, Rue Bernard Gregory, 06560 Valbonne, France Paola Castrucci; Maurizio De Crescenzi; Dipartimento di Fisica, Università di Roma Tor Vergata, via della Ricerca Scientifica1, 00133 Roma, Italy Holger Vach; LPICM, CNRS, Ecole Polytechnique, IP Paris, Palaiseau, 91128, France

Resume : Despite the large body of literature reporting on the growth of graphene (Gr) on 6H?SiC(0001) by chemical vapor deposition (CVD) [1-3], some important issues have not yet been solved, and full-wafer-scale epitaxy of Gr remains challenging, hampering applications in microelectronics. With this study, we shed light on the generic mechanism which produces the coexistence of two di?erent types of Gr domains: Gr on hydrogen (H-Gr) and Gr on bu?er layer ((6 × 6) Gr), whose proportion can be carefully controlled by tuning the H2 ?ow rate. We show for the ?rst time that the growth of Gr by CVD under a H2/Ar ?ow rate proceeds in two stages [4]. First, the nucleation of free-standing epitaxial Gr on hydrogen (H-Gr) occurs; then, H-atoms eventually desorb from either step edges or defects. This gives rise, for a H2 ?ow rate below a critical value, to the formation of (6 × 6) Gr domains. The front of H-desorption progresses proportionally to the reduction of H2. Using the robust and generic X-ray photoelectron spectroscopy (XPS) analysis, we realistically quantify the proportions of H-Gr and (6 × 6) Gr domains of a Gr ?lm synthesized under any experimental conditions. Scanning tunneling microscopy supports the XPS measurements. From these results, we can deduce that the H-assisted CVD growth of Gr developed here is a unique method to grow fully free-standing H-Gr in contrast to the method consisting of H-intercalation below (6 × 6) Gr epitaxial layer. Further description will be given in the presentation. These results are of crucial importance for future applications of Gr/SiC(0001) in nano- and microelectronics and in particular for ?eld-e?ect transistors, for which maximization of mobility is mandatory. We achieve thus a precise identification of new Gr surface structures which provide the groundwork for the use of Gr as an optimal template layer for Van der Waals homo- and heteroepitaxy for optoelectronic applications. In a last part, the two different mechanisms of growth of Silicon on each accurately monitored Gr surface are reported. [1] W. Strupinski et al., Nano Lett. 2011, 11, 1786?1791 [2] M. Portail et al., J. Cryst. Growth 2012, 349, 27?35 [3] R. Bueno et al., Appl. Surf. Sci. 2019, 466, 51?58 [4] Z. Ben Jabra et al., ACS Appl. Nano Mater. 2021, 4, 4462? 4473

Authors : Matteo Crisci (1), Paolo Dolcet (2), Peter Belteky (3), Akos Kukovecz (3), Francesco Lamberti (4), Silvia Gross (4), Teresa Gatti (1)
Affiliations : 1Center for Materials Research, Justus Liebig University, Heinrich-Buff-Ring 17, 35392 Giessen, Germany 2 Institute of Technical and Polymer Chemistry, Karlsruhe Institute of Technology, Engessestr. 20, 76131 Karlsruhe, Germany 3 Department of Applied and Environmental Science, University of Szeged, Rerrich Bela ter 1, H-6720 Szeged, Hungary 4 Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy

Resume : ?-MoO3 is a promising material for use in charge extracting layers within optoelectronic devices, due to its wide gap and deep work-function, characteristics that makes it an established constituent of ?hole transporting layers? in last generation solar cells and light emitting diodes. This material possesses a layered structure that makes it also suitable for mechanical exfoliation to produce 2D nanosheets, allowing to further tune its electronic properties. Here, we will report on the synthesis of pristine bulk MoO3 mesostructures and on their liquid phase exfoliation, that produces functional inks of few-layers 2D MoO3. The first process is carried out employing a hydrothermal synthesis, as a green and easily scalable method, while the second, makes use of both shear-mixing and tip sonication in different liquid media, so as to ascertain whether differences emerge in the resulting inks and 2D materials there contained. First characterizations, made through optical/Raman spectroscopy, dynamic light scattering and high-resolution transmission electron microscopy allows to frame the exfoliation process and identify the best conditions. In particular, we found good yields in exfoliated products employing water-based media. We then proceeded in further characterizing these materials through X-Rays Absorption (XAS) and other advanced optical and microscopy techniques to improve our understanding of their structural and functional properties for the future use in next generation optoelectronic devices.

Authors : Juanmei Duan1,2,*, Phanish Chava1,2, Mahdi Ghorbani-Asl1, Denise Erb1, Liang Hu4, Arkady V. Krasheninnikov1,5, Harald Schneider1, Lars Rebohle1, Artur Erbe1, Manfred Helm1, Yu-Jia Zeng3, Shengqiang Zhou1 and Slawomir Prucnal1
Affiliations : 1Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstrasse 400, D-01328 Dresden, Germany 2Technische Universität Dresden, D-01062 Dresden, Germany 3College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China 4Key Laboratory of Novel Materials for Sensor of Zhejiang Province, Institute of Advanced Magnetic Materials, Hangzhou Dianzi University, Hangzhou 310018, P. R. China 5Department of Applied Physics, Aalto University School of Science, Aalto FI- 00076, Finland *) Corresponding author:

Resume : Trions, quasi-particles consisting of two electrons combined with one hole or of two holes with one electron, have recently been observed in transition metal dichalcogenides (TMDCs) and drawn increasing attention due to potential applications of these materials in light-emitting diodes, valleytronic devices as well as for being a testbed for understanding many-body phenomena. Therefore, it is important to enhance the trion emission and its stability. In this study, we have fabricated a MoSe2/FePS3 van der Waals heterostructure (vdWH) with type-I band alignment, which allows for carriers injection from FePS3 to MoSe2. At low temperatures, the neutral exciton (X0) emission in this vdWH is almost completely suppressed. The ITrion/Ix0 intensity ratio increases from 0.44 in a single MoSe2 monolayer to 20 in this heterostructure. The optical pumping with circularly polarized light shows a polarization for trion emission in MoSe2/FePS3 of 14%. Moreover, forming such type-I vdWH also gives rise to a 20-fold enhancement of the room temperature photoluminescence from monolayer MoSe2. Our results demonstrate a novel approach to convert excitons to trions in monolayer 2D TMDCs via interlayer doping effect using type-I band alignment in vdWH.

Authors : Tuan Khanh Chau, Junhong Na, and Dongseok Suh
Affiliations : Department of Energy Science, Sungkyunkwan University, Suwon 16419, Korea

Resume : We report the photoelectric properties of MoS2/LaAlO3 heterointerface. Persistent photocurrent can be controlled by not only applied gate-voltage but also laser illumination, which is attributed to the generation and migration of oxygen vacancies inside LAO substrate. The wavelength-dependent photocurrent showing that only the photo-energy corresponding to the deep energy level of oxygen vacancies inside the LAO (~1.9 eV) can induce the photo-doping effect. Moreover, the photoinduced current can be precisely controlled by laser intensity and extremely low electric field (< 105 V m-1) applied across the LAO substrate. This photoinduced current is also observed with other 2D materials such as graphene and WSe2. We believe that the heterostructures lead to a novel platform for next-generation optoelectronic devices as well as the study of functional oxide materials.

Authors : Alestair Wilson, Erwann Fourmond, Bilel Saidi, Mickael Gros-Jean
Affiliations : Alestair Wilson 1) STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles, France 2) Univ Lyon, INSA Lyon, CNRS, Ecole Centrale de Lyon, Université Claude Bernard Lyon 1, CPE Lyon, INL, UMR5270, 69621 Villeurbanne,France Erwann Fourmond 2) Univ Lyon, INSA Lyon, CNRS, Ecole Centrale de Lyon, Université Claude Bernard Lyon 1, CPE Lyon, INL, UMR5270, 69621 Villeurbanne,France Bilel Saidi 1) STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles, France Mickael Gros-Jean 1) STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles, France

Resume : Finely tuning crystallinity and doping of Si, Ge and SiGe thin films is a keypoint into obtaining high quality devices for above-IC near infrared SiGe-based image sensors. This study focuses on the structural and electrical properties of HF-PECVD deposited microcrystalline silicon (µc-Si:H) contact layers. µc-Si:H typically exhibits an amorphous incubation layer which can span up to 100 nm before nucleation of the crystalline phase. In previous work done on SiGe-based P-I-N sensors the n and p type layers typically have a thickness of the order of a few tens of nanometers. It is thus of great interest to ensure doped layers exhibit an incubation layer as thin as possible, independently from the doping level, as electrical and optical properties of amorphous and microcrystalline silicon differ significantly. In this work, phosphorus doped µc-Si:H was deposited by capacitive coupled plasma HF-PECVD (13,56 MHz) from a SiH4 H2 PH3 gas mixture with varying phosphine level. Two sets of deposition conditions were investigated, i.e. « low power » and « high power » conditions. For each of these conditions, thick samples (> 100 nm) were deposited for gas flow ratios ? = PH3/SiH4 between 0 and 1 % and samples of variable thickness were deposited for a ratio ? = 0.1% . The influence of phosphine concentration in the gas mixture on dopant concentration, active dopant concentration and crystallinity was studied by SIMS, Hall effect measurement and Raman spectroscopy respectively. High doping level were attained, reaching up to 1.6x10^20 cm-3. Topography and surface defects were investigated by AFM and SEM while thickness was measured by spectroscopic ellipsometry. Deposited films show « low power » samples reach a high crystallinity for films as thin as 40 nm whereas « high power » samples transition to highly crystalline films only between 40 and 80 nm despite exhibiting clear signs of early crystallite nucleation. These « low power » conditions also contribute to a better incorporation of active phosphorus in the thin film. For both set of deposition parameters the rise of blister-like surface defects due to compressive stress in P doped µc-Si:H shows there is a thickness limit for the n-type layer above which the films no longer sticks to the substrate.

12:00 Q&A live session / Break    
Session 03- Plasmonics, Sensing, SERS : J. Adam, Y. K. Mishra
Authors : Andreas Seifert
Affiliations : CIC nanoGUNE BRTA

Resume : At properly adjusted conditions, electrons from noble metal nanostructures and nanoparticles (NPs) can resonantly interact with photons and produce plasmonic phenomena. The plasmonic response naturally depends on the metallic material, but also on geometry, dimensions and the dielectric properties of the environment. Moreover, periodic arrangements of nanostructures can add additional plasmonic features that originate from in-plane diffracted waves that can couple localized plasmon resonances of individual NPs. In addition, regularly arranged clusters of particles, that form so-called superlattices, introduce a plethora of further near-field effects and far-field coupling that can be exploited by sensing techniques. The inner structure of a unit cell of the periodic arrangement strongly influences the plasmonic response. Superlattices can generate plasmonic surface lattice resonances with high Q factors and strong near-field enhancement, and allow tunability by period, incidence angle, and polarization. There are two common pathways for the fabrication of periodic metallic nanostructures: (i) Electron beam lithography (EBL), which allows for precise placement and control of the NP shape. Corresponding nanostructures that support plasmonic lattice effects have shown interesting applications in metamaterials, nano-lasing, long-range energy transport, or structural plasmonic color generation. Unfortunately, EBL is an expensive and slow technology, and close distances between the NPs for creating hotspots of the electric field cannot be fabricated. The spatial resolution of EBL is too low for fully taking advantage of strong plasmonic coupling between NPs. ii) Self-assembly of colloidal NPs is a low-cost and fast alternative for producing plasmonic superlattices. It is based on van der Waals forces and allows for close packing of NPs with interparticle distances even below 1 nm, realized by functionalization of the surfaces. Corresponding hotspots of the electric fields at the junctions can be exploited for sensing, as for example by surface-enhanced Raman spectroscopy (SERS) or surface-enhanced infrared absorption. The talk gives examples from both nanostructured surfaces made by EBL and chemically driven selfassembly of colloidal Au NPs. The EBL structures were primarily used for optimizing plasmonic biosensing in Kretschmann configuration, where we combine dielectric with plasmonic properties and use multivariate analysis for better exploitation of the multitude of features in the reflectance curves. The developed self-assembly process allows us to assemble a controlled number of differently shaped NPs (spheres, rods, triangles) into superlattices on large-scale. Specific applications to be presented cover tunable plasmonics using stretchable substrates, precise SERS detection of selected tumor metabolites, and a new method that prevents the SERS memory effect by specific polymer coating of the substrates and laser-activated deprotection.

Authors : A. Colombelli, D. Lospinoso, R. Rella, M.G. Manera*
Affiliations : IMM-CNR Institute for Microelectronic and Microsystems, Unit of Lecce, Italy

Resume : Plasmonic nanostructures with tunable optical properties can have many applications in the field of nanophotonics and optoelectronics: sensitive optical detection of biological and chemical compounds is one of the main issues with important effects in medical research, environmental and food safety. The realization of optimized sensing platforms depends strongly on the ability to finely control optical features of nanostructures which are, in turn, intimately linked to their geometrical and compositional properties. In this work, an efficient and reproducible fabrication protocol based on a modified nanosphere lithography (NSL) method is presented: highly ordered nano-holes in thin gold films with tuning plasmonic features have been realized. Based on the self-assembly of close-packed polystyrene particles at the air/water interface, this approach enables the fabrication of a large-area colloidal mask with a high quality crystal-like structure and hexagonal symmetry, easily transferrable onto solid supports. The subsequent controlled reduction of the particle size allows to obtain a non-close-packed monolayer which is used as sacrificial mask to realize the nano-hole array by metal evaporation. The relationships between the geometric characteristics of different types of nanostructures and optical phenomena such as enhanced absorption or extraordinary transmission are investigated in detail. In particular we theoretically and experimentally studied and compare optical characteristics of four types of structures, with two different diameters and thickness, evidencing their hybrid nature as a result of an interplay between localized and propagating plasmon modes. A great electric field enhancement and local confinement are found as a consequence of interaction with light, with the possibility to modulate their optical properties according to their geometric characteristics. Optical and functional characterizations are carried out in view of their employment as optical transducers in nanoplasmonic chemosensors platforms working in the UV-VIS range. To this purpose, surface and bulk sensing parameters are investigated with the aim of monitoring optical responses when varying the contribution of surface or localized surface plasmon resonances. Their functional abilities as surface enhanced Raman spectroscopy (SERS) substrates are also explored and compared, both theoretically and experimentally, to find the best configuration to the aim of achieving single-molecule detection.

Authors : Borgh, G.(1,2,3); Bongiorno, C.(2); La Magna, A.(2); Mannino, G.(2); Patanè, S.(1); Shabani, A.(3); Adam, J.(3); Shabani, A.(3) & Puglisi, R. A.(2).
Affiliations : (1) Department of Mathematics and Computer Science, Physics and Earth Science (MIFT), University of Messina, Viale F. Stagno d?Alcontres, 31, 98166 Messina, Italy (2) National Research Council (CNR) Institute for Microelectronics and Microsystems (IMM), Strada Ottava 5, Zona Industriale, 95121 Catania, Italy (3) Computational Materials Group, Mechanical and Electrical Engineering, University of Southern Denmark, Alsion 2 DK-6400 Sønderborg Denmark

Resume : Silicon nanowires (SiNWs) are functional nanostructures for electronics in several fields such as photovoltaics, photodetectors, photocatalysis or sensing. Their synthesis can be VLS- compatible, which renders them potential candidates for large-scale applications. SiNWs exhibit unique electro-optical properties, including plasmon resonances (PRs): the collective oscillations of free electrons. An electromagnetic field can induce this phenomenon at specific frequencies, depending on the nanosystem shape and its surrounding medium. SiNWs are already used to absorb and amplify, by several orders of magnitude, radiant energy and to generate a locally amplified electric field, a beneficial mechanism in many applications. We demonstrated the longitudinal and transversal PRs in SiNWs in our recent work[1]. There is, however, no deep understanding in the literature on how the PR changes with the SiNW size. In this contribution, we report the study of the PRs triggered in SiNWs with varying diameters, pursued by high resolution electron energy loss spectroscopy, to understand how the SiNW geometry influences its plasmonic behaviour. We further support our findings with theoretical calculations to understand the PR's electric field intensity and spatial distribution upon a changing nanostructure geometry. [1] Borgh, G.; Bongiorno, C.(2); La Magna, A.; Mannino, G.; Patanè, S.; Adam, Jost and Puglisi, R. A.; ?Surface Plasmons in Silicon Nanowires? under consideration.

Authors : D. F. Carvalho (1), M. A. Martins (2), M. R. Correia (1)
Affiliations : (1) Department of Physics and i3N, University of Aveiro, Portugal; (2) Department of Materials and Ceramic Engineering and CICECO, University of Aveiro, Portugal

Resume : In recent years, several ways to improve the emission efficiency of optical devices based on semiconductor materials using metallic nanoparticles (MNPs) have been studied. MNPs exhibit very interesting optical properties related with the localized surface plasmons (LSP). Despite the numerous articles reporting an increase in the photoluminescence (PL) and electroluminescence in different semiconductors and optical devices due to the coupling with MNPs, the phenomenon of interaction is still subject of some discussion [1]. There are many studies reporting PL increase phenomena in optical devices based on GaN/InGaN quantum nanostructures, due to the impact of the increased emission efficiency in this type of structures, which are the basis of blue and white LEDs marketed nowadays. However, there are only few studies reporting a detailed study of the plasmonic effects, associated with MNPs, in the photoluminescence of GaN films [2]. In this study, a systematic study of plasmonic effects in n-type and p-type GaN films was carried out, using Au and Ag MNPs, with different sizes and shapes. The MNPs were synthesized by wet-chemical methods and were deposited on the GaN films using two different methods: drop casting and functionalization of the GaN surface with APTES molecules. This study allowed to analyze the interaction mechanisms between MNPs and the GaN films, mainly through the changes in the GaN emission bands observed by PL, whose excitation or emission process was mediated by the optical response of the MNPs. This study combines theoretical and numerical simulation of the optical properties of MNPs, morphological/topographic properties of MNPs-GaN, transmittance and PL spectroscopy. The analysis of the results revealed that the main MNPs-GaN interaction mechanisms present were the non-resonant electrostatic mechanism and the electron transfer through the interface between the MNPs and the GaN. [1] J. Lin et al., Appl. Phys. Lett., 104, (2014); [2] J. Tatebayashi et al., Jpn. J. Appl. Phys., 58, (2019). This work was developed within the scope of the project i3N, UIDB/50025/2020 & UIDP/50025/2020, financed by national funds through the FCT/MEC.

Authors : C. Mancarella*(1), L. Stasi (1), L. Tovaglieri (1), B. R. Bricchi (1), G. Terraneo (2), A. Li Bassi (1,3).
Affiliations : (1) Micro- and Nanostructured Materials Laboratory, Department of Energy, Politecnico di Milano, via Ponzio 34/3, 20133, Milano, Italy; (2) Department of Chemistry, Materials, and Chemical Engineering ?Giulio Natta?, Politecnico di Milano, via Mancinelli 7, 20131 Milano, Italy; (3) Center for Nano Science and Technology ? IIT@Polimi, via Pascoli 70/3, 20133, Milano, Italy. * lead presenter

Resume : Recently, the increasing interest to extend the excitation range and to tailor the optical response of plasmonic materials has opened the route to a new intriguing class of artificial metamaterials which enable novel functionalities. These are multi-phase nanocomposites typically in multilayer configuration, where building blocks assembled in subwavelength size and spacing accomplish ?effective? properties unattainable in independent components [1]. Hyperbolic metamaterials especially present unique electromagnetic phenomena (high-k modes) activated by the anisotropic permittivity arising from the periodic alternation of conductors and dielectrics. By selecting materials and device geometry the effective plasma frequency and light propagation can be engineered successfully, while control over nanoscale morphology, structure and electrical performance looks promising for targeted applications in nanophotonics and bio-sensing [2]. Such systems rely conventionally on plasmonic noble metals (Au, Ag) and oxide-based dielectrics (In2O3, Al2O3) to display optical features in the visible [3]. However, a less explored approach involves the selection of alternative materials (e.g. transition metal nitrides, or Transparent Conductive Oxides-TCOs with plasma frequency in the IR) and original design routes can stimulate a plethora of multifunctional meta-devices, inherently tunable and with a cross-disciplinary attitude, such as TCO-based multifunctional electrodes, photonic crystals or nano-architectures for sensing. In this framework, all-oxide transparent conducting multilayers based on the less-explored Ta-doped TiO2 (Ta:TiO2) TCO have been obtained via Pulsed Laser Deposition (PLD). We developed a simple one-step synthesis by alternating conductive (compact) and dielectric (porous) layers of the same Ta:TiO2, by varying the deposition pressure (1-6 Pa O2). Following a material science perspective, structural and electrical properties have been optimized to control optical/plasmonic outputs as a function of deposition conditions, doping content and geometrical parameters. Applications are foreseen in the aforementioned fields, e.g. hyperbolic platforms in the IR. Multilayers based on 10% Ta atomic content reveal the highest tunability of properties. The overall crystalline structure and electrical performances are ruled by the convolution of single properties of metallic and dielectric units. Besides, TiN has been integrated as metallic counterpart in novel TiN-TiO2 multilayers for operation in the visible, with features that can benefit from the refractory nature and fabrication compatibility of TiN, along with the possibility to modify the plasmonic response through stoichiometry. [1] Yao, K. et al. Nanotechnology Reviews, 3(2), 177-210 (2014). [2] Poddubny, A. et al. Nature Photonics 7, 948-957 (2013). [3] Guo, Z. et al. Journal of Applied Physics 127, 071101 (2020).

14:30 Q&A live session    
Authors : Bricchi, B.R.*(1), Mascaretti, L. (2), Naldoni, A. (2), Garattoni, S. (1), Mazza, M. (1), Bresciani, F. (1), Li Bassi, A. (1,3)
Affiliations : (1) Department of Energy, Politecnico di Milano, via Ponzio 34/3, 20133, Milano, Italy (2) Czech Advanced Technology and Research Institute, Regional Centre of Advanced Technologies and Materials, Palacký University Olomouc, ?lechtitel? 27, 78371 Olomouc, Czech Republic (3) Center for Nanoscience and Technology ? IIT@Polimi, via Pascoli, Milano, Italy * lead presenter

Resume : Plasmonic metallic structures are known for their unique ability to strongly enhance nanoscale light?matter interactions via excitation of conduction electrons triggered by specific light wavelengths, with potentiality in several applications. The traditional plasmonic materials are noble metals that significantly increase the optical absorption in the visible range. However, they suffer from poor hardness, difficult integration with standard Si manufacturing processes, low melting point, and limited spectral tunability [1]. A new class of materials has recently gained attention to potentially address such issues, i.e., transition metal nitrides. Among them, titanium nitride (TiN) has aroused the biggest interest, because its non-stoichiometric nature allows in principle to adjust the plasmonic response in the visible and near-infrared ranges by varying the synthesis conditions [2]. However, a clear understanding and a fine tuning of the optical and plasmonic properties of TiN thin films are still an open issue. This work aims at the investigation and control of the synthesis and optical properties of TiN thin films as a function of nanoscale morphology, crystallinity and stoichiometry. For this purpose, pulsed laser deposition (PLD) is exploited as synthesis technique for its versatility, which enables the control of the desired properties of the deposited species. Indeed, it is possible to switch gradually from a compact to a hierarchical nanoparticle-assembled thin film morphology by increasing the background gas pressure during deposition. The optical analysis of the deposited TiN films shows reflectance reduction with increasing porosity, while absorption increases. Notably, for particular morphologies we obtain a very strong broadband absorption and this peculiar optical behavior, combined with the refractory character of TiN, is potentially interesting for the emerging field of thermoplasmonics [3]. On the other hand, we show how to further tune the properties of polycrystalline TiN thin films by means of ion beam-assisted PLD synthesis. This peculiar procedure involves nitrogen ions that bombard the growing film during the deposition, allowing a control on the film stoichiometry and structure. As a consequence, the electrical (e.g., carrier density) and optical response (e.g., plasma frequency) of the so-obtained materials can be efficiently varied. Our results are crucial in order to understand and control the response of plasmonic TiN nanostructures. Moreover, the nanoporous TiN assemblies are fascinating new systems that can find exciting applications where the high specific surface may be exploited (e.g., solar energy harvesting and photocatalysis). [1] G.V. Naik et al. Advanced Materials 2013, 25.24, 3264-3294 [2] P. Patsalas, et al. Materials Science and Engineering: R 2018, 123, 1-55 [3] G. Baffou, et al. Nature Materials 2020, 19.9, 946-958

Authors : Ashish Prajapati and Gil Shalev
Affiliations : School of Electrical Engineering, Ben-Gurion University of the Negev, Israel

Resume : Silicon light funnels are three-dimensional subwavelength structures in the shape of inverted cones with respect to the incoming illumination. Light funnel (LF) arrays can serve as efficient absorbing layers on account of their light trapping capabilities, which are associated with the presence of high-density complex Mie modes. Specifically, light funnel arrays exhibit broadband absorption enhancement of the solar spectrum. In the current study, we numerically explore the optical coupling between surface light funnel arrays and the underlying substrates. We show that the absorption in the LF array-substrate complex is higher than the absorption in LF arrays of the same height (~10% increase). This, we suggest, implies that a LF array serves as an efficient surface element that imparts additional momentum components to the impinging illumination, and hence optically excites the substrate by near-field light concentration, excitation of traveling guided modes in the substrate, and mode hybridization.

Authors : Marco Reale; Alice Sciortino; Gianpiero Buscarino; Antonio Emanuele; Nicolò Mauro; Marco Cannas; Fabrizio Messina;
Affiliations : Dipartimento di Fisica e Chimica ? Emilio Segré, Università degli Studi di Palermo, Via Archirafi 36, 90123 Palermo (Italy); Dipartimento di Fisica e Chimica ? Emilio Segré, Università degli Studi di Palermo, Via Archirafi 36, 90123 Palermo (Italy) ATeN Center ? Università degli Studi di Palermo, Palermo (Italy); Dipartimento di Fisica e Chimica ? Emilio Segré, Università degli Studi di Palermo, Via Archirafi 36, 90123 Palermo (Italy) ATeN Center ? Università degli Studi di Palermo, Palermo (Italy); Dipartimento di Fisica e Chimica ? Emilio Segré, Università degli Studi di Palermo, Via Archirafi 36, 90123 Palermo (Italy); Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche, Università degli Studi di Palermo, Via Archirafi 32, 90123 Palermo (Italy); Dipartimento di Fisica e Chimica ? Emilio Segré, Università degli Studi di Palermo, Via Archirafi 36, 90123 Palermo (Italy); Dipartimento di Fisica e Chimica ? Emilio Segré, Università degli Studi di Palermo, Via Archirafi 36, 90123 Palermo (Italy) ATeN Center ? Università degli Studi di Palermo, Palermo (Italy);

Resume : In the last years Nanoscience is devoting a growing interest in the inexpensive assembly of well-established nanomaterials into new hybrid nanostructures, in which the properties of the precursors can be modulated, modified, or completely upset, often resulting in unique characteristics not achievable in the starting components. Here we investigated the photo-physical and -chemical response of hybrid binary nanomaterials obtained by coupling Carbon Dots (CDs) to metallic nanoparticles (MNPs). In particular, we aimed to investigate whether the strong propensity of CDs to engage in photoinduced charge-transfer1 can cooperate with the carrier mobility within MNPs, to achieve a photocatalytic response in the newly constituted nanohybrids. We obtained heavily nitrogen-doped CDs characterized by strong optical absorption-emission bands, through a simple bottom-up approach involving a thermally-induced decomposition route2. Then the CDs were coupled via a quick self-assembly method to noble-metal plasmonic nanoparticles, synthetized by the Turkevich method and engineered to have both a negative and a positive surface charge version of each type of MNP. We provide evidence of successful CDs-MNPs couplings and interactions by steady-state and time-resolved optical measurements: the optical data show a CDs photoluminescence quenching on a sub-nanosecond time scale, due to photoinduced charge transfer between the interacting nanosystems. We also find that the driving force leading to CD-MNP self-assembly is not purely electrostatic, although surface charge appears to play a role in the charge transfer processes. Finally, the photocatalytic performances of the nanohybrids were assessed by evaluating the photodegradation of methylene blue under VIS-UV light irradiation. As anticipated, some of the CD-MNP nanohybrids display a significant photocatalytic activity due to the interface charge separation triggered by light absorption. The results are very promising and encourage further studies to develop a new generation of photocatalytic carbon-based devices for pollutant degradation and water splitting under solar radiation.

Authors : Jyoti 1,*, Teresa ?o?ek 2, Dorota Maciejewska 2, Andrzej Kutner 3, Krzysztof Noworyta 1, and W?odzimierz Kutner 1,4
Affiliations : 1. Institute of Physical Chemistry, Polish Academy of Sciences (IPC PAS), Kasprzaka 44/52, 01-224, Warsaw, Poland 2. Department of Organic Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland 3. Medical University of Warsaw, Faculty of Pharmacy, Department of Bioanalysis and Drug Analysis, 1 Stefana Banacha, 02-097 Warsaw, Poland 4. Faculty of Mathematics and Natural Sciences. School of Sciences, Cardinal Stefan Wyszynski University, Woycickiego 1/3, 01-815 Warsaw, Poland

Resume : An electrochemical chemosensor was devised, prepared, and tested for detecting and quantifying an antidepressant duloxetine drug by using molecularly imprinted polymer nanoparticles (nanoMIPs) as its recognition unit. Duloxetine is an orally administered selective serotonin and norepinephrine reuptake inhibitor (SNRI), effective in major depressive disorder [1], anxiety disorder [2], and fibromyalgia [3]. Thus, the determination of this drug in body fluids is vital from the personalized drug dosage point of view. Toward that, a fast, reliable, and straightforward method was herein developed. Molecularly imprinted polymers (MIPs) are tailor-made synthetic receptors, able to specifically recognize target molecules. They are synthesized by co-polymerizing functional and cross-linking monomers in the presence of a molecular template, resulting in the formation of binding sites with affinities and specificities comparable to those of template molecule. Herein, nanoMIPs were prepared by precipitation polymerization of chosen functional acrylic monomers to selectively determine the duloxetine drug in body fluids. Interactions of the duloxetine and common biological interferents molecules with the nanoMIPs molecularly imprinted cavities were simulated with molecular mechanics (MM) and molecular dynamics (MD). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) imaging revealed the morphology of the nanoMIPs immobilized on the electrode surface. Electrochemical impedance spectroscopy (EIS) was used to determine duloxetine and the interferents with the electrochemical chemosensor fabricated. The chemosensor?s linear dynamic concentration range was 10 nM to 623 µM duloxetine and the imprinting factor was IF = 5. The chemosensor was highly stable and reusable. References [1] J M. J. Detke, D. Ph, Y. Lu, D. Ph, J. G. Watkin, D. Phil, and P. V Tran, Prim. Care Companion J. Clin. Psychiatry, 2003, 5, 19?28. [2] D. De Berardis, N. Serroni, A. Carano, M. Scali, A. Valchera, D. Campanella, A. D?Albenzio, B. Di Giuseppe, F. Saverio Moschetta, R. Maria Salerno and F. Maria Ferro, Neuropsychiatr. Dis. Treat., 2018, 4, 929?935. [3] R. P. Schukro, M. J. Oehmke, A. Geroldinger, G. Heinze, H. Kress and S. Pramhas, Anesthesiology, 2016, 124, 150?158.

Authors : Salih Veziroglu, Josiah Shondo, Tim Tjardts, Tamim B. Sarwar, Thomas Strunskus, Franz Faupel, Oral Cenk Aktas
Affiliations : Chair for Multicomponent Materials, Institute of Materials Science, Kiel University, 24143 Kiel, Germany

Resume : Noble metal (Au, Ag, and Pt, etc.) micro-and nanostructures have been received exceptional attention during the last decades, due to their unique structural, electronic, and catalytic properties. Especially, the incorporation of these micro-and nanostructures with wide-bandgap metal oxide semiconductors such as titanium oxide (TiO2) and zinc oxide (ZnO) has been shown many times for various applications such as photocatalysis 1,2, water splitting, self-cleaning3, sensor applications and so on. There are various studies about the synthesis of micro-and nanostructures with well-defined size and morphology in the literature. However, it is still a challenge to achieve good adhesion between micro and nanostructures and metal oxide structure especially with TiO2 thin film surface. Therefore, some approaches (seed-mediated growth, etc.) have been published to enhance the adhesion of metallic micro-and nanostructures on TiO2 thin film by using some binder molecules (thiols and silanes, etc.). Mostly organic molecules are used for binding metallic micro-and nanostructures with a solid substrate. However, these may decrease the surface conductivity and contaminate the surface which affects the activity of the metallic micro-and nanostructures. Similarly, electrodeposition methods can also be used to prepare metallic micro-and nanostructures on the solid substrates. But the electrodeposition process works only on the conductive substrate such as indium tin oxide (ITO). Therefore, there is a need to prepare stable Au or Ag micro-and nanostructures on TiO2 thin films without using any organic molecules (binders) or a conductive electrode. Here, we demonstrate a novel photocatalytic deposition approach for preparing Au and Ag micro-and nanostructures on TiO2 thin film surface by UV illumination with strong chemical adhesion for wide-range applications such as photocatalytic degradation of organic compounds, self-cleaning and oil-water separation. This method allows the controlling the geometry, size, and distribution of such Au and Ag micro-and nanostructures on TiO2 thin film by simply changing the deposition solution, photocatalytic activity of metal oxide, UV illumination intensity, and time. References 1 S. Veziroglu, M. Z. Ghori, M. Kamp, L. Kienle, H. G. Rubahn, T. Strunskus, J. Fiutowski, J. Adam, F. Faupel and O. C. Aktas, Adv. Mater. Interfaces, 2018, 5, 1800465. 2 S. Veziroglu, M. Z. Ghori, A. L. Obermann, K. Röder, O. Polonskyi, T. Strunskus, F. Faupel and O. C. Aktas, Phys. Status Solidi Appl. Mater. Sci., 2019, 1800898. 3 J. Shondo, S. Veziroglu, D. Stefan, Y. K. Mishra, T. Strunskus, F. Faupel and O. C. Aktas, Appl. Surf. Sci., 2021, 537, 147795.

15:45 Q&A live session    
Session 04- Publisher Talk: EMRS Special Issue : Y. K. Mishra, J. Adam, D. Janas, R. Puglisi, L. Polavarapu
Authors : Hannah Kerr
Affiliations : Royal Society of Chemistry

Resume : This presentation will discuss how the publishing process at the Royal Society of Chemistry works, including practical hints for preparing manuscripts. Particular focus will be given to the nanoscale journal family, introducing how these journals work together and how to select which journal is right for you.

Authors : Marc Zastrow, Stefan Hildebrandt
Affiliations : Wiley-VCH GmbH, Berlin, Germany

Resume : Following a previous successful publication from the E-MRS Fall Symposium K in 2018, we publish once again a Special Issue in pss (a) – applications and materials science highlighting the exciting results of this E-MRS Fall 2021 Symposium R. physica status solidi is one of the largest and well-established publication platforms in solid state, applied, and device physics, as well as materials science with about 1000 articles per year – now 60 years in business – and widely accessible as part of many national and institutional site licenses and through an increasing number of Open Access agreements. Evidenced by many hundreds of thousands of article downloads annually, this Special Issue in physica status solidi will make your important works available to a large international audience quickly. Moreover, the publications of your paper in physica status solidi includes the following further benefits: No page charges for authors, modern article formats (PDF, Enhanced PDF, HTML, Enhanced Article for mobile devices), and a Wiley Open Access option compliant with funder mandates and supported by many institutions and countries. Furthermore, physica status solidi is indexed in Web of Science and all other major abstracting databases.

17:00 Q&A live session / Break    
Poster Session R : D. Janas, J. Adam, R. Puglisi, L. Polavarapu, Y. K. Mishra
Authors : І.І. Gab, T.V. Stetsyuk
Affiliations : Frantsevich Institute for Materials Science Problems of NAS of Ukraine

Resume : In this work, the dispersion of double niobium-copper films deposited onto samples of leucosapphire, alumina and zirconium ceramics were investigated when annealed in vacuum at temperatures of 900 ÷ 1100 ° C with exposure at these temperatures from 5 to 20 min. The thickness of the niobium layer was 150 nm and the thickness of the copper layer, which subsequently served as a solder to joining the above ceramics was 1,5 μm. The study found that, the first slight changes in integrity of the original niobium-copper films onto oxide materials appeared only after 20 min at this temperature. The situation did not change virtually with increase of the annealing temperature up to 1000 °C, at which noticeable changes in the films morphology were found also after 20 min of exposition. Raising the annealing temperature up to 1050 °C intensified the process of changing the films morphology, which was noticeable already after 10 min of exposition. After 20 min of annealing, there was a noticeable tendency for the dispersion in the films, although they were still covering even more than 80% of the substrate surface. Significant dispersion of the films was caused only by annealing at 1100 °C, when the copper had to be already in molten state, which is clearly visible after 5 min of exposition. After 10 min of exposition, and especially after 20 min of annealing, the films were strongly dispersed, although their residues were still covering more than 70% of the substrates surface area. According to the results of the studies, kinetic decay curves of the investigated thin double metal films were constructed, by which the basic technological parameters of the processes of joining ceramic materials by soldering or welding using data prototypes of data connections were made ceramic with a soldering gap of 2  3 mcm. The shear strength of the obtained ceramic joints was ~ 150 MPa.

Authors : Ergashov Yokub Suvonovich
Affiliations : Tashkent State Technical University named after I. Karimov

Resume : Nanoscale structures created on the surface and in the near-surface region of semiconductor and dielectric films have prospects in the creation of new devices for micro-, opto- and nanoelectronics. It is known that the electronic properties of multilayer heterostructures are mainly overestimated by the parameters of the energy bands, in particular, by the band gap ?g of individual films included in the composition of the heterostructures. To determine the value of Eg (and other parameters of the energy bands), the method of elastically reflected slow electrons spectroscopy, UVES, and also the method of light absorption when passing through thin films are widely used. Each of these methods has certain advantages and disadvantages. The main disadvantage of the this methods is the impossibility of determining the parameters of the zones of nanocrystalline phases created in the near-surface region of materials. In addition, with a decrease in the band gap Eg of the material, the accuracy of estimating Eg decreases. In the case of the light transmission method, the main disadvantage is the impossibility of assessing the value of the electron affinity ?. In this method, it is assumed that the Eg of the investigated film is less than the Eg of the substrate. The table shows the parameters of the energy bands of the CoSi2 film, determined by various methods (?v is the ceiling of the valence band relative to vacuum). It can be seen that with an increase in the value of ?g, the measurement accuracy by the SURE and UVES methods significantly increases, and when using the light transmission method, it does not change significantly. In this work, the energy band parameters of nanofilms CoSi2 and SiO2 were determined for the first time by three independent methods. Films CoSi2 were obtained by MBE on the Si (111) surface, and SiO2 - on the surface CaF2 (111) . The results show that the light transmission method is the most efficient and accurate method for determining Eg. However, to obtain complete information about the density of state of electrons and the parameters of energy bands, it is necessary to carry out studies using a set of methods of UVES, ERES and light transmission. To determine ?g of nanofilms or phases created at different depths of the surface layer, we mainly used the method of light transmission. In this case, the value of ? was estimated by calculation or on the basis of experimental data obtained for the same structures created on the surface. Research in this direction continues.

Authors : Riya Wadhwa, Mukesh Kumar*
Affiliations : Functional and Renewable Energy Materials Laboratory, Department of physics, IIT Ropar, Rupnagar 140001, Punjab, India

Resume : Two Dimensional (2D) Van der Waals heterostructures are becoming one of the ascendant research areas for solid-state device fabrication because of their excellent electronic and optoelectronic properties, which can access more functioning ability beyond its individual constituent. 2D layered materials easily integrated and formed heterostructure due to the dangling bond free surfaces. However, for novel electronic/optoelectronic device applications, it is very critical to understand the charge carrier dynamics at the interface of heterostructures. Here, we investigated the band-alignment at MoS2-ReS2 heterointerface through photoelectron spectroscopy. Photoelectron spectroscopy reveals the formation of type ? alignment at the interface, which is beneficial for charge transportation and photovoltaic device applications. As a proof of concept, a highly sensitive, self-driven, broadband photodetector is fabricated with a responsivity of 42.61 A/W at low bias of 1V under the illumination of 800 nm, which is 16 folds higher than the reference pristine MoS2 photodetector. The favorable energy band alignment of this n-n hetero-junction is responsible for enhanced photo-responsivity and self-driven feature of the detector. Moreover, fast rise/decay transient photoresponse (20/19 ms) strongly advocate the spatial separation of charge carrier across the interface. This work facilitates the understanding of fundamental interfacial study of a new growing van der wall heterostructures for the development of novel device applications.

Authors : Edgars Butanovs, Valts Minders, Boris Polyakov
Affiliations : Institute of Solid State Physics, University of Latvia, Kengaraga street 8, Riga, Latvia, LV-1063

Resume : Gallium oxide Ga2O3 has recently attracted a lot of scientific attention as a prospective ultra-wide bandgap (UWBG) semiconductor in a form of thin films and nanowires (NWs). While Ga2O3-based thin films and heterostructures have been researched extensively in the last few years mainly for applications in power electronics and UV photodetectors, Ga2O3-based hybrid NW materials still lack the variety of studies, especially in the core-shell configuration. Here, we demonstrate growth of different core-shell NW heterostructures with Ga2O3 NW core and few-nm thick Ga2S3, Ga2Se3 or ZnGa2O4 shell. Ga2S3 and Ga2Se3 are semiconductors with a narrower bandgap than Ga2O3 thus giving freedom to tune optical properties in the visible range, while ZnGa2O4 is potential p-type UWBG semiconductor. Ga2S3 and Ga2Se3 shell was obtained during high-temperature sulfurization or selenization process of Ga2O3 NWs, respectively, in a chemical vapour transport reactor. ZnGa2O4 shell was synthesised in a two-step process: atomic layer deposition of ZnO coating and subsequent annealing at high-temperature. As-grown heterostructures were characterized by scanning and transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and photoluminescence measurements. Such as-grown core-shell NW heterostructures could be used in next-generation nanoscale electronic and optoelectronic devices. The financial support of ERAF project is greatly acknowledged.

Authors : Honoka TANABE,Yohei SHIGEORI,Kazuma NIWA,Kento IWAI,Soshi YAMASITA,Kimihiro YAMANAKA,Hirohisa TAGUCHI
Affiliations : Chukyo University,Department of Electrical and Electronic Enginineering School of Engineering,2-101,Yagoto-Honmachi,Showa Ward,Nagoya City,Aichi Pref.,Japan

Resume : In various aspects of our lives, Cu plating is used as a base for plastic products used in exterior automobile parts and as a surface treatment for metal materials. However, it is not widely known that three-dimensional dendritic crystals (Cu dendrite crystals) are formed when the Cu plating process is performed on difficult-to-plate materials, such as ZnAl alloy plates. Herein, we have studied the formation process of Cu dendrite crystals. One of the methods used to form Cu dendrite crystals is a plating process using a supersaturated Cu sulfate aqueous solution. In addition, electroless plating and electroplating are conventionally used techniques. Cu was used as the anode to perform the plating process. For the cathode, a ZnAl alloy plate in which an Fe plate superposed was used. In this experimental system, we confirmed that a thin film of Cu was formed and that Cu dendrite crystals grew from this thin film. In previous studies, a Cu plate is used as the cathode instead of an Fe plate. In this case, a Cu sheet with a skeleton structure formed by entwining Cu dendrite crystals was precipitated. The thin film of Cu was confirmed for the first time in this experiment using an iron plate. Furthermore, Cu crystals exhibiting a face-centered cubic lattice structure (FCC) were formed when the duration of the electric field plating process was extended under the conditions in which the thin film was formed. By investigating the amount of FCC crystals deposited at each electroplating time, we found a relationship between the appearance of the FCC crystals and electroplating time. The principle of Cu dendrite formation interpreted from the appearance of the FCC crystals was as follows: 1) The Cu skeleton structure is formed on difficult-to-plate materials. 2) The Cu dendrite formation occurs at an arbitrary position (two-dimensional growth mode). 3) The Cu ions are supplied from the Cu dendrite crystals toward the ZnAl substrate to reshape the thin film of Cu. 4) The precipitation of FCC crystals (original Cu crystal formation) corresponds to the final product due to the further supply of Cu ions. From our results, the true origin of the Cu dendrite crystals is an intermediate reaction that occurs during the Cu precipitation process. From the relationship observed between the electroplating time and the amount of FCC precipitated, we found that the transition between Cu dendrite crystals and FCC is repeated multiple times during the electroplating process. This transition process depends on the change in the Cu ion density in the solution. Therefore, it was found that Cu dendrite crystals are formed every time the Cu ion density reaches a specific condition.

Authors : Yohei SHIGEMORI, Honoka TANABE, Hayate KINOSITA, Kimihiro YAMANAKA, Hirohisa TAGUCHI
Affiliations : Department of Electronic Engineering School of Engineering Chukyo University 2-101, Yagoto-Honmachi, Showa Ward, Nagoya City, Aichi Pref., Japan 4668666

Resume : Research on metal nanoparticles is accelerating toward the realization of wearable devices using conductive ink. Typically, metal nanoparticles are made of gold or silver; however, this is limited by the high manufacturing costs. Copper is the cheapest precious metal. In our research so far, we have succeeded in producing and mass-producing Cu dendrite crystals with a three-dimensional dendritic structure, which are aggregates of thin film structures and extremely fragile. Copper fine particles can be obtained by pulverizing this structure. However, Cu aggregates without being made into fine particles when it is broken by a method that directly applies mechanical energy. Thus, it is necessary to indirectly apply energy to form Cu fine particles by pulverizing the Cu dendrite structure. In this study, to indirectly apply mechanical energy to the Cu dendrite structure, a microbubble crushing method using an ultrasonic homogenizer was employed. Further, a conductive ink was prepared using the obtained copper fine particles, and it had electric resistivity equivalent to that of commercially available materials . The detailed experimental method is presented below. Substitution plating and electrolytic plating were performed on a zinc-aluminum alloy plate, which is a challenging material for plating, resulting in copper dendrite crystals formed on the zinc-aluminum alloy plate. This plate was pulverized using an ultrasonic homogenizer. Then, the Cu fine particles were heated in an oxidation furnace to form a Cu oxide film on the surface of the fine particles. The finished Cu oxide fine particles were pulverized again with the ultrasonic homogenizer. After pulverization, the Cu oxide fine particles were reduced using dilute hydrochloric acid . Thereafter, Cu fine particles were placed on an insulating sheet to obtain a conductive paste, and were observed using a SEM after drying. The conductivity of the conductive paste was also examined using a four-terminal method. The results of crushed copper dendrite without oxidation and copper dendrite that was crushed to form an oxide film were compared. Many spherical particles with smaller particle sizes were observed on the side where the oxide film was formed. Next, the copper fine particles were reduced and particles of approximately 100 nm were obtained. The resistivity value measured for the conductive paste was 1.9×10^(-7) Ω∙m. It was observed that the Cu fine particles forming the oxide film were selectively oxidized at the crystal grain interface and that the structure itself was fragile. Furthermore, the final hydrochloric acid treatment removed the oxide film coated on the surface, which contributed to the trimming of the fine particle shape. To ensure dispensability of the fine Cu particles, it is necessary to consider future surfactant effect.

Authors : Hayate KINOSHITA, Yohei SHIGEMORI, Honoka TANABE, Kimihiro YAMANAKA, Hirohisa TAGUCHI
Affiliations : Department of Electrical and Electronic Engineering School of Engineering Chukyo University 2-101, Yagoto-Honmachi, Showa Ward, Nagoya City, Aichi Pref., Japan 4668666

Resume : Communication equipment, such as smartphones, requires further miniaturization in the future. Miniaturization of individual electronic devices is necessary, but circuit board miniaturization is also an important issue. The arrangement of lumped constant circuit type electronic devices on an epoxy substrate is being replaced by distributed constant circuits. Furthermore, the distributed constant circuit requires increased flexibility by being printed on an insulating film, not epoxy substrates. Therefore, it is crucial that the conductive ink circuit pattern is printed onto the insulating film. Silver nanoparticles are generally produced by solution precipitation. However, in this study, we succeeded in making nanoparticles by pulverizing silver dendrite crystals via an indirect method. Silver, similar to gold, is difficult to miniaturize for indicating malleability with a direct breaking method. Therefore, to indirectly apply mechanical energy, the silver dendrite crystal is first micronized by ultrasonic vibration; then, silver nanoparticles are formed using shock waves from an ultrasonic homogenizer. The specific experimental method is shown below. A silver dendrite crystal is prepared using a silver nitrate solution and an oxygen-free copper plate. It can be performed by an electric field plating method using the ionization tendency. Silver dendrite crystals were formed while applying ultrasonic waves (40 kHz/120 W) during electroplating. It is expected that a tree-like structure at the silver dendrite crystal formation stage crushes when ultrasonic vibration is applied. This silver dendrite structure crushing is performed to make it possible to create a smaller silver crystal structure. Using the abovementioned method, the dendritic structure, which is a dendrite structure characteristic, could be removed. In addition, the silver crystals are needle-shaped aggregates, and the aggregate diameters are approximately 3–5 μm. This micro-sized silver crystal aggregate was pulverized by an ultrasonic homogenizer. After the fine particles were completely formed, the targeted silver fine particles were observed using a scanning electron microscope, confirming successful nanoscale particle formation. In particular, when hydrochloric acid treatment was performed on the silver fine particles for residual impurity removal, silver fine particle spheroidization was confirmed. Silver dendrite crystals themselves can be easily generated; moreover, all products can generate crushed silver nanoparticles. Hence, its industrial advantages are expected over the conventional method.

Authors : Yi Li, Juanmei Duan, Manfred Helm, Shengqiang Zhou, Slawomir Prucnal
Affiliations : Yi Li; Juanmei Duan; Manfred Helm; Shengqiang Zhou; Slawomir Prucnal; Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden, Germany. Yi Li; Juanmei Duan; Manfred Helm; Technische Universität Dresden, 01062 Dresden, Germany

Resume : The precise control of dopant concentration and distribution in two-dimensional materials (2D), e.g. transition metal dichalcogenides (TMDs), is a major problem on the way to their successful application in modern nanoelectronics. Efficient doping can be achieved by substituting chalcogenide atoms with group V or VII atoms, intercalations or electrostatic doping. In the present work, both the optical and electrical properties of mechanically exfoliated 2D TMDs have been modified using NH3 plasma treatment for 10 s followed by short-time annealing. After plasma treatment, the TMDs flakes were investigated by photoluminescence (PL) and Raman spectroscopies and current-voltage (I-V) characteristics. After NH3 plasma treatment, the PL-peak intensity of the MoSe2 monolayer degrades and shifts towards lower energy (higher wavelength) due to hydrogen doping. Annealing after plasma treatment releases hydrogen and the PL emission returns to normal. The same has been observed in Raman spectra. H-doping causes a shift of the main phonon modes due to the phonon-plasmon coupling, i.e. Fano effect. The I-V characteristics also clearly confirm the efficient hydrogen doping of the MoSe2 monolayer. This work shows new insights into controllable doping in 2D materials.

Authors : S. Scurti.*, D. Caretti, N. Dimitratos
Affiliations : Industrial Chemistry “Toso Montanari” Department, University of Bologna, Viale Risorgimento 4, 40126 Bologna, Italy

Resume : Gold nanoparticles have been utilized by several research groups for the wastewater remediation. In particular the large use of nitroaromatic compounds as intermediates in organic synthesis and their strong pollutant nature have created the necessity to develop novel green catalytic treatments to convert pollutants in useful chemical compounds. An interesting example is the catalytic reduction of 4-nitrophenol (4-NP), a significant side product obtained from anthropogenic activity. Additionally, it is defined by the health organization as a hazardous product, and its removal from the environment is an important goal because of the negative effects on human and animals.[1,2] In this work, the effect of reaction temperature combined to the effect of poly(vinyl-alcohol-co-vinyl-acetate) stabilizers in terms of copolymer composition on preformed gold colloidal nanoparticles supported on active carbon (AuNPs/AC) was investigated. The 4-nitrophenol catalytic reduction with NaBH4 as the chosen reducing agent, has been used to investigate the catalytic activity of synthesized Au/AC catalysts. Different characterization techniques were used for analysing the morphology of the nanostructured materials, and therefore to correlate the properties of the functionalised polymer used as stabiliser, with the average Au nanoparticle size and finally with the observed catalytic activity and stability.[3] Moreover, temperature-dependent study was conducted by Arrhenius theory and the thermodynamic parameters related to the nanostructured materials were calculated. (1) Qian, al J. Chem. Technol. Biotechnol. 2013, 88 (5), 735–741. (2) Bowers, G. N. et al Clin. Chem. 1980, 26(6), 724-729. (3) Scurti, S. et al Nanomat. 2021, 11 (4), 879.

Authors : L. Salemi, M. Condorelli, L. D'Urso, G. D'Arrigo, M. Scuderi, G. Compagnini
Affiliations : Department of chemistry, university of Catania; Department of chemistry, university of Catania; Department of chemistry, university of Catania; CNR IMM-HQ Catania; CNR IMM-HQ Catania; Department of chemistry, university of Catania

Resume : Noble metal nanoparticles are particularly suitable for certain sensing applications, owing to their strong plasmonic resonances in the visible spectrum. In many instances, it is desirable to control the position of the nanoparticles on a substrate, such as for the implementation of nanoparticle based sensors in electronic circuits or to obtain substrates with differently functionalized regions. This result is often achieved by in-situ bottom-up approaches, common of microfabrication. Nanoparticle synthesis in the colloidal state is often advantageous compared to other alternatives, because of low costs and high scalability. Additionally, it provides the possibility to obtain many different shapes and sizes by controlling the chemical environment and other synthesis parameters. Depending on the application, nanoparticles in the colloidal form can then be used “as prepared” or after depositions on solid substrates via a number of different functionalization processes. In this work we present a template guided deposition of noble metal nanoparticles. The template is obtained by an electron beam lithographic approach, performed onto a polymer thin film. We then illustrate the technique and characterize the final patterned samples.

Authors : Marcello Condorelli1, Lucio Litti2, Mario Pulvirenti1, Vittorio Scardaci1, Moreno Meneghetti2, Giuseppe Compagnini1*.
Affiliations : 1Department of Chemical Sciences, University of Study of Catania, Viale Andrea Doria 6, 95125, Catania, Italy. 2Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131, Padova, Italy

Resume : Surface plasmon resonance (SPR) sensors find wide applications due to their prompt responses and because they do not need sophisticated instrumentation. One of the most explored effects is the high sensitivity of the plasmon band position due to refractive index changes in the medium. In the following, we present a cost-effective, reusable, and high-responsive SPR device based on silver nanoplate paved PMMA cuvettes. The nanostructures were obtained by the seed-growing approach. The localized surface plasmon resonance (LSPR) features, observed in the colloidal state, were successfully transferred to the paved cuvettes and their plasmon sensitivities with liquids of different refractive index were recorded. We observed refractive index sensitivities up to 280 nm/refractive index units, using nanoplates with plasmon resonances in the near-infrared region. The experimental results find correspondence and agreement with extinction cross-section calculated with a Boundary Element Method (BEM) approach. This work addresses how to build a simple, cost-effective optical device, which is suitable for integration and miniaturization.

Authors : Izzi, M*(1)(2), Picca, R.A.(1)(2), Leonardi, A.A.(3)(4), Lo Faro, M.J.(3)(4), Sportelli, M.C.(1), Irrera A.(4) & Cioffi, N.(1)(2).
Affiliations : (1) Chemistry Department, University of Bari Aldo Moro, Bari, Italy (2) CSGI (Center for Colloid and Surface Science), Bari, Italy (3) Physics Department, University of Catania, Catania, Italy (4) IPCF-CNR, Messina, Italy * lead presenter

Resume : Hybrid nanomaterials combining semiconductor and metal nanostructures represent an efficient way to develop novel platforms for advanced applications. In particular, silicon nanowires (SiNWs) decorated with metal nanoparticles could be successfully exploited in analytical and sensing applications, ensuring a strong improvement in the electric and optical signals, providing up-and-coming substrates for potential optical sensors or Surface-Enhanced Raman Spectroscopy. In this communication, we report on the modification of SiNW platforms by electrophoretic deposition (EPD) of chemically produced AuNPs. SiNWs are prepared by a wet-etching technique, assisted by the deposition of an ultrathin metal film on (p-, n-doped or highly doped) Si single crystal [1]. AuNPs are synthesized by mean of an innovative synthesis based on stainless steel as solid reductant for HAuCl4 [2]. Pros and cons of EPD of preformed NPs will be highlighted in comparison with the direct reduction of gold precursors on SiNW surface. The role of silicon doping will be investigated in combination with the charge of AuNP surface, to evaluate their influence on final material properties. To this aim, the results obtained on their electrochemical, spectroscopic and morphological characterizations will be presented. [1] A. Irrera et al., Semicond. Sci. Technol. 2017, 32, 043004. [2] M. Izzi et al., Nanomaterials 2020, 10, 622.

Authors : V. Marinova1, D. Dimitrov1,2, K. Buchkov1,2
Affiliations : 1Institute of Optical Materials and Technologies-Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; 2 Institute of Solid State Physics-Bulgarian Academy of Sciences, 11784 Sofia, Bulgaria

Resume : Transition metal dichalcogenides (TMDCs) are large family of layered materials that show unique properties (different from their bulk counterparts) when thinned down to nanoscale thicknesses. TMDCs with stable metallic and semi-metallic phases (e.g., the 1T or 2H phase of TaS2, 1T-TiSe2, 2H-NbSe2, and Td-WTe2) are attractive for investigations of charge density waves (CDW), superconductivity, magnetoresistance, and other topological phases of mater [1]. The preparation of WTe2 as monolayer or few layers by MOCVD and CVD is found to be challenging, therefore a bulk single crystal method is sought in order to obtain crystal samples with good quality. In this study WTe2 single-crystals were synthesized through Chemical Vapor Transport (CVT) method using Br2 as transport agent. WTe2 orthorhombic Td structure is confirmed by single crystal and powder X-ray diffraction. The structure is further verified by Raman spectroscopy analyses. Layered morphology and elemental composition stoichiometry are observed by SEM and EDS respectively. Acknowledgement: This research was supported by the European Union’s Horizon 2020 research and innovation programme FETPROACT, under grant agreement No. 824140 Reference: 1. H. Li et al. Epitaxial Growth of Two-Dimensional Layered Transition-Metal Dichalcogenides: Growth Mechanism, Controllability, and Scalability. Chem. Rev. 118, 6134-6150 (2018)

Authors : Jyoti 1,*, Teresa ?o?ek 2, Dorota Maciejewska 2, Andrzej Kutner 3, Krzysztof Noworyta 1, and W?odzimierz Kutner 1,4
Affiliations : 1. Institute of Physical Chemistry, Polish Academy of Sciences (IPC PAS), Kasprzaka 44/52, 01-224, Warsaw, Poland 2. Department of Organic Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland 3. Medical University of Warsaw, Faculty of Pharmacy, Department of Bioanalysis and Drug Analysis, 1 Stefana Banacha, 02-097 Warsaw, Poland 4. Faculty of Mathematics and Natural Sciences. School of Sciences, Cardinal Stefan Wyszynski University, Woycickiego 1/3, 01-815 Warsaw, Poland

Resume : An electrochemical chemosensor was devised, prepared, and tested for detecting and quantifying an antidepressant drug, duloxetine, by using molecularly imprinted polymer nanoparticles (nanoMIPs) as its recognition unit. Duloxetine is an orally administered selective serotonin and norepinephrine reuptake inhibitor (SNRI), effective in major depressive disorder [1], anxiety disorder [2], and fibromyalgia [3]. Thus, the determination of this drug in body fluids is vital from the personalized drug dosage point of view. Toward that, a fast, reliable, and straightforward method was herein developed. Molecularly imprinted polymers (MIPs) are tailor-made synthetic receptors, able to specifically recognize target molecules. They are synthesized by co-polymerizing functional and cross-linking monomers in the presence of a molecular template, resulting in the formation of binding sites with affinities and specificities comparable to those of template molecule. Herein, nanoMIPs were prepared by precipitation polymerization of chosen functional acrylic monomers to selectively determine the duloxetine drug in body fluids. Interactions of the duloxetine and common biological interferents molecules with the nanoMIPs molecularly imprinted cavities were simulated with molecular mechanics (MM) and molecular dynamics (MD). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) imaging revealed the morphology of the nanoMIPs immobilized on the electrode surface. Electrochemical impedance spectroscopy (EIS) was used to determine duloxetine and the interferents with the electrochemical chemosensor fabricated. The chemosensor?s linear dynamic concentration range was 10 nM to 623 µM duloxetine and the imprinting factor was IF = 5. The chemosensor was highly stable and reusable. References [1] J M. J. Detke, D. Ph, Y. Lu, D. Ph, J. G. Watkin, D. Phil, and P. V Tran, Prim. Care Companion J. Clin. Psychiatry, 2003, 5, 19?28. [2] D. De Berardis, N. Serroni, A. Carano, M. Scali, A. Valchera, D. Campanella, A. D?Albenzio, B. Di Giuseppe, F. Saverio Moschetta, R. Maria Salerno and F. Maria Ferro, Neuropsychiatr. Dis. Treat., 2018, 4, 929?935. [3] R. P. Schukro, M. J. Oehmke, A. Geroldinger, G. Heinze, H. Kress and S. Pramhas, Anesthesiology, 2016, 124, 150?158.

Authors : Asgar Huseynov1, Samira Mammadova2 Eldar Zeynalov 1, Sevda Abdullayeva2
Affiliations : 1. Institute of Catalysis and Inorganic Chemistry, ANAS 2. Institute of Physics, ANAS

Resume : The results of a study on the synthesis of carbon nanofibers (CNF) by the Chemical Vapour Deposition method (CVD) are presented. In order to reduce the cost of the target product, distillate oil fractions – gasoline, jet fuel and diesel-were tested as raw carbon materials. Ferrocene was used as a precursor of the catalyst. The peculiarities of the formation of CNF, as well as carbon impurities of non – tubular structure, were revealed, depending on the changes of synthesis conditions - the hydrocarbon composition of the raw material, pressure and temperature. It is shown that at atmospheric pressure, the formation of CNF occurs only in the case of the participation of the gasoline fraction of oil as a raw material. At the same time, carbon fibers are contaminated with coke layers. Carrying out the process at reduced pressures leads to the formation of the target product and in the case of use the jet fuel as a raw material.In addition, the reduced pressure contributes to the formation of a CNF with a smaller diameter and fewer coke impurities. The scientific interpretation is given to explain the revealed patterns, including the use of the Le Chatelier’s principle.

Authors : Jorge Sanz Mateo, Federica Benes, Daniel Kiener, Marco Deluca
Affiliations : Materials Center Leoben Forschung GmbH, Roseggerstraße 12, 8700 Leoben Austria; Chair of Material Physics, Department Materials Science, Montanuniversität Leoben, Jahnstrasse 12, 8700 Leoben, Austria

Resume : In recent years, lead free perovskites have proved to be a safe choice as materials with high energy storage density for applications in dielectric capacitors. Among them, BaTiO3-based materials are receiving increasing attention in the research community. The recent drive for miniaturisation has moved the focus from bulk to thin film form due to their small volume and excellent dielectric properties. Among the deposition procedures, the sol-gel route coupled with spin-coating has been chosen for its high versatility, simplicity and possibility of large-scale production at low costs. This method also allows a high control of the microstructure, grain orientation and film thickness by tuning the concentration of the solution and the deposition parameters like temperature, time, and atmosphere. This easy manufacture makes thin films more desirable for the design of miniaturised electronics than their ceramic counterparts. However, a thorough characterisation of materials synthesized by sol-gel techniques is needed in order to understand their structural properties and how they affect their performance, in order to improve it especially in terms of energy density. The present thin films were produced by sol-gel synthesis using organic precursors, spin-coating on platinized Si substrates and subsequent rapid thermal annealing. They are composed of grains of around a hundred nanometres diameter, therefore, analytical techniques that can go down to such a scale are needed. High Resolution Transmission Electron Microscopy (HRTEM) is an appropriate method to analyse these films, as it can visualise their structure from the whole film cross-section down to the atomic scale, and based on the collected data the phase and polarisation can be obtained. This work shows the application of wedge polishing to produce TEM samples out of the produced thin films. Using this preparation method, cross section samples allowing for atomic scale visualisation were achieved. This procedure only requires a multiprep machine and a precision ion polishing system (PIPS), therefore avoiding any focussed ion beam (FIB) preparation that could introduce artificial crystal defects. Multiple grains were visualised successfully, resolving the atomic columns at diverse orientations. The perovskite structure of the material was identified and an analysis of multiple grains was possible with respect to their domain boundaries, planar defects and overall structure using a JEOL F 2100 with a spherical aberration corrector working at 200 keV. For comparative reasons, also bulk BaTiO3 samples were prepared and analysed in the same manner. The latter results will be used to discuss the macroscopic properties of the sol-gel derived thin film material in comparison to the reference bulk ceramic.

Authors : M. Shegeda (1), V. Barbash (2), O. Gomenyuk (3), T. Isokov (1), K. Krolenko (1), S.G. Nedilko (1), V. Scheludko (3), V. Scherbatskii (1), O. Yashchenko (2).
Affiliations : 1 - Taras Shevchenko National University of Kyiv, 64/13 Volodymyrska st., Kyiv 01033, Ukraine; 2 - National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, prospect Peremogy 37, Kyiv, Ukraine; 3 - O. Dovzhenko Hlukhiv National Pedagogical University, Hlukhiv 41400, Ukraine.

Resume : Today, flexible electronics devices use polymers that are products of petrochemistry. Therefore, there is a strong demand for the replacement of such polymers with materials of natural origin. Nanosized cellulose (NC) made from plants or synthesized by bacteria in the form of nanofibrils networks (bacterial cellulose or in other words – biocellulose (BC) is an example of natural polymer [1]. The NC properties can be modified by substitution of its hydroxyl groups with some functional groups, such as specific acids, chlorides, oxides or dyes to enrich some characteristics or to obtain new properties. The NC properties can also be modified by incorporation of micro/nanosized particles and microcrystalline cellulose (MCC) as well as carbon nanoparticles (CNPs) are among them. Two types of NC samples were made by us and then their morphology, structure and physical properties were studied. First, of the samples sets were prepared from Common reed and Miscanthus x Giganteus plant [2]. The second set of the NC samples was prepared on the base of the BC matrix. The black tea, sugar and Komagataeibacter xylinus were used to obtain that type of the BC raw samples. Then, the BC samples were washed in running water and soaked in water for a long time. After, the samples were soaked in a 2% solution of NaOH for 24 hours and washed with acetic acid solution. Finally, the samples were washed with distilled water to neutral pH and dried. The hybrid NC composite samples were made on the base of NC filled with MCC particles and/or CNPs. Some of the samples were functionalized with dyes and Rhodamine C was particularly used to give BC new luminescent properties. Various characterization procedures have been used to study structural, mechanical and optical properties of elaborated nanostructured cellulose films. The samples were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), optical reflectance, ellipsometry, and scattering of light, FTIR, Raman and luminescence spectroscopy. Some mechanical characteristics such as hardness and tensile strength were measured too. The obtained data were analyzed with the aim to state a correlation between both mechanical, structural characteristics and optical properties.

Authors : B. Rodríguez, P. Hidalgo, B. Méndez
Affiliations : Departamento de Física de Materiales, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040-Madrid, Spain.

Resume : Transition metal oxides nano- and microstructured are considered promising candidates for multiple applications in electrochromic devices, catalysers, gas sensors, and so forth, because of their attractive properties. One of these metal oxides is WO3, a wide-bandgap n-type semiconductor representative of the electrochromic group materials. In this work, we report a very rapid synthesis of WO3 nano- and microstructures via the resistive heating of a metallic tungsten wire. This method has already been demonstrated as an effective route to obtain other metallic oxides, such as MoO3 [1]. The growth mechanism is discussed in terms of diffusion processes associated with the flow of an intense electric current and local oxidation processes on the surface of the wire [2]. The thermally assisted electromigration process gives rise to the formation of hierarchical structures (fern-shape and cubic) of WO3 in a wide size range over the wire surface. On the other hand, by applying an external electric field oriented parallel to the electric current flow, i.e. to the wire, WO3 nanospheres and nanocrystals are deposited on the electrodes. The structural analysis by means of Raman spectroscopy and X-ray diffraction shows that the structures grown on the wire are WO3 in monoclinic, triclinic and orthorhombic phase, as well as monoclinic and with oxygen deficiency for the structures grown in the electrodes. The growth mechanisms for both WO3 micro- and nanostructures are discussed. The results obtained show that it is a simple and effective method to synthesize tungsten oxide in a fast and low-cost way with promising applications. References [1] B. Rodríguez, P. Hidalgo, J. Piqueras and B. Méndez, RSC Adv., 10, 11892 (2020) [2] S. K. Lin, Y. C. Liu, S. J. Chiu, Y. T. Liu and H. y. Lee, Sci. Rep. 7, 3082 (2017)

Authors : David Batet, Eloi Ramon, Juan Pablo Esquivel, Gemma Gabriel
Affiliations : Instituto de Microelectrónica de Barcelona, (IMB-CNM, CSIC), C/ del Til·lers, Campus UAB, Bellaterra, 08193, Barcelona, Spain Universidad Autónoma de Barcelona (UAB), Bellaterra, 08193, Barcelona, Spain Centro de Investigación Biomédica en Red en Bioingeniería Biomateriales y Nanomedicina (CIBER-BBN), Madrid, 50018, Spain

Resume : Management of Waste from Electrical and Electronic Equipment is a major concern, due to the dramatic increase in the amount of this waste and the usage of toxic substances in electronic devices. The fabrication of biodegradable devices would help to mitigate this problem. In this work, different paper-based substrates were selected owing to their biodegradability for the fabrication of an electrochemical sensor. On the other hand, composites of different carbon materials, including graphene and graphite, and cellulose nanofibers (CNF) were deposited using additive manufacturing technologies on these paper substrates. Blended CNF would facilitate the degradation of the composites. For a complete electrical characterization, squares of each composite were printed and their sheet resistance measured. Composites were also electrochemically characterized in phosphate buffer saline and potassium ferrocyanide/ferricyanide solution to evaluate their potentiality as electrode for sensing and energy applications. The measured properties of each substrate were studied as a function of their composition, i.e. the carbon material used and the proportions of conductive and cellulosic material.

Authors : Konstantinos Brintakis [1], Kyriaki Savva [1], Athanasia Kostopoulou [1], Emmanuel Stratakis [1,2]
Affiliations : [1] Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Heraklion, 71110, Crete, Greece; [2] Physics Department, University of Crete, Heraklion, 710 03 Crete, Greece

Resume : Photonic processes such as photothermal, photochemical or photophysical were implemented in colloids in order to fabricate nanocrystals of different morphologies or to modify the size or morphological features of pre-formed nanocrystals. Besides the plethora of reports on laser-based fabrication or size/structure modification of nanocrystals of different -materials, only a few works referred to metal halide perovskite nanocrystals. The limited results have led to poor knowledge/understanding on the interactions of the laser irradiated photon with these materials in these dimensions. These limited works concern the pulsed laser fragmentation in liquid environment, starting from material in powder to form nanocrystals or the alteration of the nanocrystal stoichiometry via an anion exchange with the halides originated from the solvent (dihalomethane). [1,2] Till now, different morphologies and structures of metal halide perovskite nanocrystals have been synthesized by tuning the parameters of the chemical synthesis such as ratio between the precursors, the time of the reaction, the quantity of the ligands and the temperature of the synthesis. In order to obtain nanocrystals of different morphologies for comparing their properties or application performance, different syntheses have to be carried out, which is a time- and chemicals consuming process. Here we report on a simple and rapid photo-induced method to modify the shape and the dimensionality of metal halide nanocrystals via ultrashort-pulsed laser irradiation of their colloids. Furthermore, conjugations of metal halide nanocrystals with 2D materials could be obtained by similar photo-triggered method. [3] This rapid and single-step room temperature method provides unique opportunities for the cost-effective fabrication of single- or multi-phase nanostructures with controllable size, shape, and dimensionality. The transformation from one to another nanostructure and the conjugation of two distinct material allows new fundamental studies on the impact of dimensionality and morphology to the final physical properties as well as to new synergetic effects. [1] Dong et al., J. Phys. Chem. Lett. 2019, 10, (15), 4149-4156. [2] Parobek et al., J. Am. Chem. Soc. 2017, 139, (12), 4358-4361. [3] Kostopoulou et al., Nanomaterials 2020, 10 (4), 747. Acknowledgments: A.K. acknowledges the Hellenic Foundation for Research and Innovation (HFRI) and the General Secretariat for Research and Technology (GSRT) (under grant agreement No 1179), and K.B. EU H2020 Research and Innovation Program under G.A. N820677 and IKY through the operational Program «Human Resources Development, Education and Lifelong Learning» in the context of the project “Reinforcement of Postdoctoral Researchers - 2nd Cycle” (MIS-5033021), for the funding. Also, we acknowledge FLAG-ERA Joint Transnational Call 2019 for ERA-NETS 2019b (PeroGaS: MIS 5070514).

Authors : U. Vounckx, B. Joos, M.K. Van Bael, A. Hardy
Affiliations : Hasselt University, Institute for materials research, DESINe, Martelarenlaan 42, 3500 Hasselt, Belgium; Hasselt University, Institute for materials research, DESINe, Martelarenlaan 42, 3500 Hasselt, Belgium/ imo-imomec, division of imec, Wetenschapspark 1, 3590 Diepenbeek, Belgium; Hasselt University, Institute for materials research, DESINe, Martelarenlaan 42, 3500 Hasselt, Belgium/ imo-imomec, division of imec, Wetenschapspark 1, 3590 Diepenbeek, Belgium; Hasselt University, Institute for materials research, DESINe, Martelarenlaan 42, 3500 Hasselt, Belgium/ imo-imomec, division of imec, Wetenschapspark 1, 3590 Diepenbeek, Belgium;

Resume : Mesostructured inorganic materials are promising for applications such as catalysis, separation or drug delivery. These materials possess unique features such as controllable particle size, large surface area and uniform pore size, in addition to low density and thermal stability. Mesoporous silica with vesicular morphologies has attracted great attention for their applications in the loading and delivery of drug molecules. While mesostructured silica possesses high chemical and mechanical stability, it remains biodegradable. Compared to hollow mesoporous silica, multilamellar vesicular silica is superior in terms of loading capacity and adsorption-desorption abilities. Multilamellar vesicular silica has a higher surface to volume ratio and therefore relatively large surface to bind and carry drugs. Multilamellar vesicular silica has been synthesized by Zhang et al. By varying the molar ratio of cosurfactants, the number of layers varied between 7 and 2. Nevertheless, the pore volume of these structures is low compared to more conventional mesoporous silica, e.g. SBA-15. The goal of this study is to adjust mesoporosity of the multilamellar vesicular silica. Multilamellar vesicular silica is synthesized via a cationic-cationic cosurfactant synthesis. The molar ratio of cetyltrimethylammonium bromide (CTAB) and didocyldemethylammonium bromide (DDAB) is kept constant, while the silica precursor amount (tetraethyl orthosilicate) is varied. Since the multilamellar vesicular silica particles’ size is only relying on the CTAB-DDAB micelles, the particle size is not affected by the amount of silica precursor. However, lowering the precursor concentration causes an increase of the surface area and pore volume in the multilamellar vesicular silica. Varying the mesoporosity of these structures will affect the loading capacity and the biodegradability. To elucidate all these factors, characterization methods have been performed using tools such as: nitrogen sorption, TEM, DLS, UV-VIS, TGA. This study delivers multilamellar vesicular silica for which the surface to volume ratio and density can be adjusted by varying the precursor concentration. The particle size is not affected, while mesoporosity can be gradually increased. This allows to increase the loading capacity as deemed necessary, without changing the primary properties of the particles. [1] Zhang, Y.; Zhou, G.; Sun, B.; Zhao, M.; Zhang, J.; and Chen, F. Chemical Communications 2014, 50, 2907 [2] Pang, J.; Li, X.; Zhou, G.; Sun, B.; Wei, Y. RSC Advances. 2015, 5, 6599 This project receives financial support from FWO (1S06920N) and UHasselt (BOF19OWB29)

Authors : Ahmed Alanazi1, and James Rice* 1.
Affiliations : Physics school, University Collage Dublin

Resume : Surface-enhanced Raman scattering (SERS)-active nanomaterials have expanded from noble metals and transition metals to semiconductor materials, since the first observed in 1973 for pyridine adsorbed on a roughened silver electrode. Heterojunctions formed using plasmonic metals with semiconductors, researchers-launched heterojunction engineering into the plasmon-free SERS fields, providing a new way to obtain ultrasensitive plasmon-free SERS substrates. Moreover, it was approved that the coupling of metals and semiconductors can lead to remarkable enhancement of photoinduced intermolecular charge transfer (PICT) processes. Here we employ Photo-induced-enhanced Raman spectroscopy on Semiconductors-metals for self-cleaning SERS. These SERS substrates can be reusable and hence it is promising for applications in areas such as environmental detection or medical diagnostics.

Authors : Andreea Costas,1* Nicoleta Preda,1 Camelia Florica,1 Stefan Antohe2 and Ionut Enculescu 1
Affiliations : 1 National Institute of Material Physics, 405A Atomistilor Street, 077125, Magurele, Romania 2 Faculty of Physics, University of Bucharest, 405 Atomistilor Street, 077125, Magurele, Romania *

Resume : Metal oxide nanowires have focused the interest of the scientific community due to their potential applications in fields such as photocatalysis, photodetectors, light emitting diods, sensors, nanoscale electronics, etc. Recently, many combinations of preparation methods, like electrochemical deposition, electrospinning, sol-gel, thermal oxidation, hydrothermal, magnetron sputtering, chemical vapor deposition, atomic layer deposition, etc, have been used to obtain metal oxide core-shell nanowire arrays with advanced functionalities provided by the radial heterojunction formed between the two metal oxides. By aligning two n-type and p-type semiconductor metal oxides (e.g. ZnO, TiO2, CuO or ZnSe) into a core-shell heterostructure, a p-n staggered gap heterojunction is achieved between the two semiconductors promoting a good control of the charge carrier generation at the interface. Thus, metal oxide core-shell nanowire arrays were prepared using thermal oxidation or hydrothermal and magnetron sputtering. Different shell thicknesses were taken into consideration in order to find an optimum one. The morphological, structural, optical and compositional properties of the metal oxide core-shell nanowire arrays were studied. Moreover, their electrical and photoelectrical properties were investigated for applications in optoelectronic devices.

Authors : V. Marinova1, D. Dimitrov1,2, M. Gospodinov2
Affiliations : 1 Institute of Optical Materials and Technologies, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria 2 Institute of Solid State Physics-Bulgarian Academy of Sciences, 11784 Sofia, Bulgaria

Resume : Topological insulators are materials that are insulators in bulk however, conductors on its surface. The electric current circulating in a topological insulator does not suffer any loss of energy. This property opens great possibilities of application in electronics, since it would enable the fabrication of more efficient, faster and low-energy consumption devices. For technological applications one of the challenges has been the creation of a magnetic topological insulator. Magnetic topological insulators usually are created by the so-called extrinsic route, which consists of doping nonmagnetic topological insulators with magnetic atoms. Recently the first intrinsic magnetic topological insulator, with chemical formula MnBi2Te4 was predicted theoretically (1). In this study MnBi2Te4 crystals are prepared by using High Temperature Solution (HTS) method. Millimeter-sized MnBi2Te4 single crystals are successfully grown and characterized using EDS, XRD, Raman spectroscopy and SEM. The elemental composition close to the stoichiometric was obtained by EDS. The as-grown MnBi2Te4 single crystal exhibits layered structure, which is composed of a septuple Te-Bi-Te-Mn-Te-Bi-Te sequences as determined by powder X-ray diffraction and SEM. Eg and A1g Raman active modes typical for MnBiTe compounds are observed. Magnetic and transport properties are measured on crystals and exfoliated film samples. Acknowledgement: This research was supported by the European Union⤙s Horizon 2020 research and innovation programme FETPROACT, under grant agreement No. 824140 Reference: 1. M.M. Otrokov et al. Prediction and observation of an antiferromagnetic topological insulator. Nature 576, 416⤓422 (2019)

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Session 05 -Nanoscale: Modeling, Theory & Validation : J. Adam, R. Puglisi
Authors : Søren Peder Madsen
Affiliations : Department of Mechanical and Production Engineering, Aarhus University Inge Lehmanns Gade 10, building 3210, 8000 Aarhus C, Denmark

Resume : Upconversion of sub-band-gap photons is a promising technique for improving the efficiency of silicon-based solar cells beyond the Shockley-Queisser limit. Trivalent Erbium ions are well suited for upconversion from 1500 nm to 980 nm, but their small absorption cross section limits the efficiency. Topology optimization of gold nanostructures can be used to enhance the efficiency and the optimized nanostructure geometry can be produced using electron beam lithography. The talk will introduce a simple rate-equation model for upconversion and discuss how topology optimization is used to design gold nanostructures to optimize the amount of upconverted light. Numerical and experimental results will be presented.

Authors : Saskia Fiedler1,2 , P. Elli Stamatopoulou1, Christian Wolff1, Christos Tserkezis1, Hiroshi Sugimoto3, Minoru Fujii3, N. Asger Mortensen1,4 and Søren Raza5
Affiliations : 1University of Southern Denmark, Centre for Nano Optics, Campusvej 55, 5230 Odense M, Denmark; 2Federal Institute for Materials Research and Testing, Biophotonics, Richard-Willstätter-Straße 11, 12489 Berlin 3Department of Electrical and Electronic Engineering, Kobe University, Rokkodai, Nada, Kobe 657-8501, Japan 4Danish Institute for Advanced Study, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark 5Department of Physics, Technical University of Denmark, Fysikvej, DK-2800 Kongens Lyngby, Denmark

Resume : In this work, Mie resonances in single Si nanoparticles (NPs) of different sizes have been systematically studied, using dark field (DF) and cathodoluminescence (CL) spectroscopy. An analytical method has been developed to compare experiment with theory. Experimental CL spectra are averaged over entire Si NPs, allowing for direct comparison to DF spectra of identical NPs. Theoretical spectra clarify the assignment of Mie resonances within the NP which contribute with different intensity in DF and CL, resulting in an apparent spectral shift. Furthermore, a substrate effect appears. A 100 nm-Si NP on 15 nm SiN results in a broad peak, spectrally in between that of the calculated electric and magnetic dipole, a NP on 50 nm SiN exhibits two separated peaks as theoretically predicted. High spatial resolution of electron beam excitation allows to study the spectral CL changes at varying beam impact parameters. Theory and experiment agree that depending on beam position within a small Si NP, relative intensity of electric and magnetic dipole change; electric dipole vanishing in the center of the NP. Similar results are found for larger (d = 210 nm) Si NPs although the mode assignment is challenging as higher order modes appear and overlap with others. In conclusion, comparison of CL and DF spectra is not trivial, in fact, excitation/radiation of distinct Mie resonances within a single Si NP are dependent on beam placement. However, substrate effects need to be considered in CL.

Authors : Matiyas Tsegay Korsa, Mathias Charconnet, Søren Petersen, Andreas Seifert, Jost Adam
Affiliations : Computational Materials Group, Department of Mechanical and Electrical Engineering, University of Southern Denmark, Sønderborg 6400, Denmark CIC nanoGUNE BRTA, 20018 San Sebasti an, Spain, Spain CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), 20014 San Sebastian, Spain IKERBASQUE - Basque Foundation for Science, 48009 Bilbao, Spain

Resume : Due to their unique ability to con ne light to the nanoscale, plasmonic nanoparticles are the topic of investigation in photovoltaics, nano-sensors, drug delivery, and nano-optics. Furthermore, the optical response of these materials can be tuned and optimized for different applications by controlling the shape, size, and configuration of nanoparticle assemblies. In this regard, the modelling of nanoparticles plays a significant role in obtaining optimized nanostructures. To predict the optical response and to support experimental results of regular self-assembled plasmonic nanoparticle supper-lattices, we modelled different combinations and geometric parameters of nanoparticle clusters using the finite element method (FEM). The FEM simulations show a strong increase in the degrees of freedom with increasing particles per cluster, which enormously increases computational time, making optimization routines impossible for a large cluster of nanoparticles. Nevertheless, the optical response of particle clusters shows that the plasmonic modes arise from the single-particle mode, coupling modes, and the cluster lattice etc. Here, we present a statistical approach to predicting the plasmonic response of a sample. Scanning electron microscope (SEM) image processing of self-assembled nanoparticles gives the statistical information of cluster morphologies and distribution on the substrate. Based on the image processing input, we optimize linear combinations of FEM models to predict the whole sample's optical response. We support and verify our results by the experimental extinction curves of self-assembled nanoparticle samples. Our results indicate the potential of predicting the plasmonic effect of the large-scale particle cluster arrangements from the response of single, varying clusters.

Authors : Jieli Lyu, Damien Alloyeau, Cyrille Hamon, Doru Constantin
Affiliations : Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France. Laboratoire Materiaux et Phenomenes Quantiques, Universite de Paris CNRS, F-75013, Paris, France

Resume : We study the assembly kinetics of surfactant-stabilized gold nanoparticles in the presence of sulfate ions. The reaction proceeds in two steps: very rapid (a few minutes) formation of amorphous aggregates, followed by slow reordering (over several hours). The latter process is the only one detectable via absorbance spectroscopy and results in the formation of intimate contacts between the objects, with interparticle distances below the thickness of a surfactant bilayer. The rate-limiting step of the reaction could be related to surfactant expulsion from the initial aggregates, which allows the particles to come in close contact and form chains. There are marked differences in reaction yield and rate constant between spheres, rods and bipyramids, highlighting the role of surface curvature in contact formation. Once formed, the assemblies are very sturdy and stable under centrifugation and dialysis. The contact interaction is strong and highly directional, as shown by liquid-cell transmission electron microscopy.

Authors : Miquel López Suárez, Walter Tarantino
Affiliations : Università degli Studi di Cagliari

Resume : Cluster-assembled metallic films show interesting electrical properties, both in the near-to-percolation regime, when deposited clusters do not form a complete layer yet, and when the film thickness is well above the electrical percolation threshold. Correctly estimating their electrical conductivity is crucial, but, particularly for the latter regime, standard theoretical tools are not quite adequate. We therefore developed a procedure based on an atomically informed mesoscopic model in which ab-initio estimates of electronic transport at the nanoscale are used to reconstruct the conductivity of molecular dynamics simulated films of tens of clusters using an effective resistor network that appropriately accounts for ballistic transport. The method is shown to correctly capture one of the signature features of such systems, the non-monotonic behaviour of the conductivity as a function of the film thickness.

09:30 Q&A live session    
Authors : Philip Lucke [1], Muharrem Bayraktar[1], Andrey Yakshin[1], Guus Rijnders[2], Fred Bijkerk[1], Evert P. Houwman[2]
Affiliations : [1] Industrial Focus Group XUV Optics, MESA+ Institute of Nanotechnology, University of Twente, Enschede; [2] Inorganic Material Science, MESA+ Institute of Nanotechnology, University of Twente, Enschede

Resume : Hysteresis is a limiting factor for the actuation accuracy of PbZr1-xTixO3 (PZT) ceramics and thin films. Explanation of hysteresis for these materials using phenomenological models such as Rayleigh model is a common practice. On the other hand, application of Rayleigh model and its variants results in significant discrepancies in explaining the hysteresis behavior in epitaxial thin films. Here, hysteresis in application-relevant, epitaxial, monoclinic PbZr0.55Ti0.45O3 films were investigated for non-switching AC excitation fields at zero and 20 kVcm-1 DC bias cases. The hysteresis, loss and nonlinearity in the strain and polarization response of the films show unique features that is not expected from the Rayleigh model. The strain exhibits a hysteretic behavior and is linear with the excitation amplitude. However, the polarization is hysteretic and highly nonlinear over the investigated frequency range from 70 Hz to 5 kHz. The application of the bias shows almost no change for the strain response, whereas the loss tangent and nonlinearity of the polarization are significantly reduced. The observations are explained by a new model, the so called polarization rotation model. This model describes the film properties as a result of the nonlinear rotation of the polarization vector within the monoclinic unit cell in response to the applied electric field, accompanied by a viscous interaction of the domains. The model can describe the scaling of the loss tangent and (non)linearity of the strain and polarization in an amplitude and frequency range that is far exceeding the applicable range of the Rayleigh model. It is shown that the nonlinear response and the hysteretic loss can be ascribed to two separate processes. The nonlinearity stems from the nonlinear nature of the rotation of the polarization vector. On the other hand, the hysteresis and ferroelectric loss stems from viscous interactions of domains during the rotation of the polarization vector. [1] Lucke, P., Bayraktar, M., Birkhölzer, Y. A., Nematollahi, M., Yakshin, A., Rijnders, G., . . . Houwman, E. P. (2020). Hysteresis, Loss and Nonlinearity in Epitaxial PbZr0.55Ti0.45O3 Films: A Polarization Rotation Model. Advanced Functional Materials, 30(52), 2005397. doi: [2] Lucke, P., Bayraktar, M., Schukkink, N., Yakshin, A. E., Rijnders, G., Bijkerk, F., & Houwman, E. P. Influence of DC Bias on the Hysteresis, Loss, and Nonlinearity of Epitaxial PbZr0.55Ti0.45O3 Films. Advanced Electronic Materials, 2100115. doi:

Authors : Chukova O.1, Nedilko S.A.1, Nedilko S.G.1, Voitenko T.1, Androulidaki A.2, Manousaki A.2, Papadopoulos A.2, Savva K.2, Stratakis E.2
Affiliations : 1 Taras Shevchenko National University of Kyiv, Volodymyrska Str., 64/13, Kyiv 01601, Ukraine; 2 Institute of Electronic Structure & Laser (IESL) of Foundation for Research & Technology Hellas (FORTH), Heraklion 711 10 Crete, Greece

Resume : Luminescent materials based on RE-activated vanadates are widely used for various science and technology purposes because the vanadates are characterized by high optical absorption in a wide spectral range, effective energy transfer from the hosts to activator RE ions, and by intensive emission. Within our previous research we have found conditions of synthesis those allowed to achieve high intensity of luminescence emission of the RE-doped vanadate nanoparticles synthesized by sol-gel method. The next important task is to save high optical characteristics of oxide nanoparticles at their deposition on various substrates. It is important to prevent loses of luminescent characteristics of nanoparticles with their incorporation in films and various coatings. One of the perspective ways to save luminescent properties of the applied nanoparticles is pulsed laser deposition (PLD), because this method doesn?t require nor any matrices for dispersion of nanorarticles like a polymeric (silicon) matrix for the YAG:Ce particles used in WLEDs, neither heavy metal or organic solvents as in liquid phase epitaxy method. In the work we report results of experiments with pulsed laser deposition (PLD) of the RE-activated lanthanum vanadate nanoparticles on glass and silicon substrates. The applied vanadate nanoparticles were synthesized by aqueous nitrate-citrate sol-gel method using citric acid as a complexion agent. The deposition of nanoparticles was carried out using KrF excimer laser with ?gen = 248 nm. Peculiarities of the PLD process of the vanadates was reported previously very shortly and mainly for yttrium and neodymium vanadates. Therefore, various experimental attempts were carried out in order to find optimal experimental conditions such as pulse power, repetition rate, and deposition duration. The conclusion was made about favorable conditions for pulsed laser deposition of vanadate nanoparticles on glass and silicon substrates. Morphology and spectral properties of the obtained samples were investigated. It was found that nanoparticles forming the films have morphology (shapes and sizes of nanoparticles and their agglomerates) similar to those in free powders. Luminescent properties of the films are also similar to ones observed for the nanoparticles before deposition. Thus, the applied method of deposition allowed us to safe properties of nanoparticles in the composite films.

Authors : D. Raciti*, G. Calogero, G. Fisicaro, I. Deretzis, & A. La Magna
Affiliations : CNR Institute for Microelectronics and Microsystems (CNR-IMM), Catania, Italy * lead presenter

Resume : We propose a method for predicting the Chemical Vapor Deposition (CVD) epitaxial growth of SiGe-based structures, using an extension of the open-source “MulSKiPS” code developed by our group and demonstrated for the Physical Vapor Deposition (PVD) epitaxy of 3C-SiC. MulSKiPS is a Kinetic Monte Carlo super-Lattice (KMCsL) code, designed to study at atomic resolution the growth kinetics of materials with sp3 bond symmetry. Its super-lattice nature makes the code unique within Lattice KMC codes. The evolution of point-like and extended defects can be predicted as a function of the initial substrate condition, without labelling the substrate lattice points. In addition, the morphology evolution during growth/etching processes - e.g. of flat, structured, or patterned substrates, or nanoparticles – can be simulated, correlating morphology and defect kinetics. The ensemble of chemical reactions occurring in the vapor phase or at the solid-vapor phase boundary is effectively accounted for by the absorption/desorption and attachment/detachment atomistic processes, which are the active Monte Carlo events, dependent on the atom configurations and on the experimental conditions. We present the method and provide some case studies, highlighting the difference between PVD and CVD processes and the dependence of growth rates on process parameters - e.g. nature and pressure of precursors and carrier gases, temperature, substrate orientation. Quantitative predictions of the microstructural evolution of the studied systems can be compared with the structural characterization of actual samples.

Authors : Michele Ghini, Nicola Curreli, Matteo B. Lodi, Nicolò Petrini, Alessandro Fanti, Ilka Kriegel
Affiliations : Functional Nanosystems, Istituto Italiano di Tecnologia (IIT), via Morego 30, 16163 Genova, Italy; Functional Nanosystems, Istituto Italiano di Tecnologia (IIT), via Morego 30, 16163 Genova, Italy; Department of Electric and Electronic Engineering (DIEE), University of Cagliari, Piazza D'Armi, 09123 Cagliari, Italy; Functional Nanosystems, Istituto Italiano di Tecnologia (IIT), via Morego 30, 16163 Genova, Italy; Department of Electric and Electronic Engineering (DIEE), University of Cagliari, Piazza D'Armi, 09123 Cagliari, Italy; Functional Nanosystems, Istituto Italiano di Tecnologia (IIT), via Morego 30, 16163 Genova, Italy

Resume : The optical and electronic properties of metal oxide nanocrystals (MO NCs) strongly depend on the surface depletion regions, derived from the presence of surface states. Moreover, MO NCs exhibit a localized surface plasmon resonance (LSPR), offering tunable characteristics enabled by doping, or via electrochemical or photochemical charging. Dynamic control over the LSPR makes MO NCs promising for several optoelectronic and storage applications. For these reasons, by manipulating the NC depletion width, it is possible to control the features of the NC. However, the mechanism behind this phenomenon is very complex, and not yet fully understood. In particular, it is possible to engineer the depletion region by varying various parameters, including the material under consideration, the size of the NCs, the presence of multiple core-shell systems, etc. To do this, it is possible to calculate the band and carrier density profiles for NCs with different features. In this work, a new framework has been introduced that can predict the behavior and physics under the MO NC photodoping process, revealing that the charging mechanism is unexpectedly based on the electronic rearrangement of the energy bands. Numerical simulations were experimentally supported by studying the case of a core-shell structure of Sn:In2O3/In2O3 NCs, by tuning the thickness of the shell, as well as post-synthetically, both by photodoping and reversible chemical reactions. The engineering of the depletion layer and the consequent manipulation of the electronic structure allows to significantly increase the sensitivity of LSPR and to target specific properties in MO NCs. The fine-tuning of the NCs? band structure has enabled an improvement in charge storage capacity, which represents a step towards fully light-driven energy storage devices.

10:40 Q&A live session / Lunch Break    
Session 06- Perovskites Nanomaterials (Symposium R & F Joint Session) : L. Polavarapu, R. Hoye
Authors : Angshuman Nag
Affiliations : Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune 411008, India

Resume : Hybrid perovskites like (C4H9NH3)2PbI4 have fascinating layered crystal structure with periodic nanoscale interfaces between the inorganic {PbI4}2- and organic C4H9NH3+ layers. Because of these interfaces, electron and hole are confined in atomically thin {PbI4}2- inorganic well layers. Therefore, these layered perovskites are considered as electronically 2D systems, irrespective of their crystallite sizes.1,2 Importantly, the crystal structure is flexible, allowing a number of combinations of different organic cations and inorganic anions. So a rational design of the nanoscale interfaces, and hence, tunable optoelectronic properties are feasible. For example, excitonic binding energy can be controlled over an order of magnitude from a few tens of meV to a few hundreds of meV, with simple variation of composition of organic cations. Furthermore, one can introduce new intermolecular chemical interactions between organic cations, resulting into completely water stable low dimensional hybrid perovskite.3 In this talk, I will discuss about how controlling nanoscale interface between organic and inorganic layers can yield interesting optical, optoelectronic and chemical properties.4 But note that the nanoscale properties will be discussed using millimeter sized single crystals. 1. ACS Energy Lett. 2018, 3, 2940. 2.Phys. Chem. Chem. Phys. 2021, 23, 82. 3. Angew. Chem. Int. Ed. 2021, DOI: 10.1002/anie.202105883 4. Angew. Chem. Int. Ed. 2020, 59, 11653.

Authors : Anna Lucia Pellegrino, Graziella Malandrino
Affiliations : Dipartimento di Scienze Chimiche, Universita' degli Studi di Catania, and INSTM UdR Catania, Viale A. Doria 6, I-95125 Catania, Italy.

Resume : The compounds belonging to the family of perovskites show a great variety of mechanical, magnetic and optical properties, and for these reasons are nowadays key materials for many technologies, including piezoelectrics, photovoltaic solar cells and photocatalytic systems. Among them, all-inorganic halide perovskites (AIHP) represent an emergent class of material, which has many advantages, such as high stability, outstanding optical properties and low-cost. In particular, our attention is devoted to CsPbBr3 and CsPb2Br5 all-inorganic perovskites, which, unlike hybrid structures, show high performances for photocatalytic and photo-electrochemical degradation processes of different organic dye compounds, and are also exceptional candidates as photocatalysts for organic reactions. In fact, one of the most emerging applications of AIHP materials regards the wastewater purification process of textile effluents from industrial production. In this field, heterogeneous catalysis under light is widely accepted due to its high efficiency, yield of degradation and cost effectiveness. Among the different strategy developed for the AIHP materials synthesis, the surfactants-based solution route is widely applied, which also allows to control the stability and the growth kinetics according to the surface chemical phenomenon and the solubility equilibrium. Herein we report a novel synthetic strategy, which represents a facile, one-step, low-temperature and surfactant free approach to the synthesis of Cs-Pb halide perovskites. The present precipitation approach represents an innovative and interesting strategy of synthesis, which avoids the use of surfactant species and toxic solvents and, taking advantage of the Cs and Pb ?-diketonate compounds as precursors, it allows, reproducibly and selectively, the synthesis of CsPbBr3 and CsPb2Br5 perovskite phases. The final products are influenced by the synthetic parameters such as aging time and heating treatment. Structural, morphological and compositional analyses of the final products have been addressed through X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and Energy Dispersive X-ray (EDX) analysis. Moreover, as a proof-of-concept, the photocatalytic properties of degradation processes have been tested using organic dye solutions, under both UV lamp (?:360 nm) and visible light source.

Authors : José Mendoza Carreño (1), Nicolás Passarelli (1), Clara Otero (2), Laksminarayana Polaravapu (2), Luis A. Pérez(1), Sebastián Reparaz (1), Maria Isabel Alonso(1), Agustín Mihi (1)
Affiliations : (1) ICMAB; (2) CINBIO

Resume : Cesium Lead halide perovskite nanocrystals are one of the most promising candidates for portable lasers and light sources. In order to harness this potential, the nanocrystals are often accompanied by a photonic environment that helps manage and improve the light emission. In this work, we report on an efficient quasi-3D photonic crystal composed of a 2D-grating on top of a distributed Bragg reflector (DBR). The optical properties of this quasi-3D system outperform those of each individual component since it supports both a series of Rayleigh-Wood anomalies and a series of guided modes populating the photonic bandgap of the Bragg mirror. In order to demonstrate the improved efficacy of the quasi-3D system in comparison with the alternative 2D-gratings and DBRs, we decorated all the systems with metal halide perovskite nanocrystals and studied the photoluminescence enhancement produced in each case. Interestingly, the quasi-3D system exhibited a PL enhancement of 16 times, exceeding the values observed for the separate components.

Authors : Rita B. Cevallos-Toledo,[a] Ignacio Rosa-Pardo ,[a] Raúl Arenal ,[b] Víctor Oestreicher, ,[a] Michael Fickert, ,[c] Gonzalo Abellán, ,[a] Raquel E. Galian, *,[a] and Julia Pérez-Prieto*,[a]
Affiliations : a Instituto de Ciencia Molecular (ICMOL), Universidad de Valencia, C/Catedrático José Beltrán 2, 46980, Paterna, Valencia, Spain bInstituto de Nanociencia y Materiales de Aragon (INMA), CSIC-U. de Zaragoza, Calle Pedro Cerbuna 12, 50009 Zaragoza (Spain) c Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU). Nikolaus-Fiebiger Strasse 10, 91058 Erlangen and Dr.-Mack Strasse 81, 90762 Fürth (Germany)

Resume : Colloidal lead halide perovskites (LHPs) are relatively new semiconductor materials which are of great interest due to their exceptional optoelectronic properties.[1] They can be classified as all-inorganic or organic-inorganic hybrids of APbX3 formula (where A can be a small-sized organic or metal mono-cation, respectively), and X is a halide anion; they present a three-dimensional (3D) inorganic framework. LHPs can also be prepared with other stoichiometries and different morphologies.[2] Thus, two-dimensional hybrid Ruddlesden–Popper (2D-RPs) lead halide perovskite (LHPs) nanostructures[3] are cutting-edge; they present a L2[APbX3]n−1PbX4 formula, where “L” usually represents a long-chain alkyl or aromatic ammonium ligand and “n” is an integer which stands for the number of atomic lead halide layers held together by weak van der Waals interactions, and sandwiched between organic layers. They exhibit different features from those of typical 2D perovkites: i) they are integrated by quantum well structures, thus exhibiting a strong quantum confinement due to their thickness (below the Böhr radius of the material); ii) the quantum confinement occurs without physically thinning the material down to the atomic thickness; and consequently iii) the emission peaks appear at the same wavelength as long as the [An−1PbnX3n+1] layer thickness is homogeneous, independently of its lateral dimensions; iv) the excitonic absorption and emission peaks are exceptionally narrow, with a small Stokes shift (<10 meV). Ruddlesden-Popper LHPs can be scaled down to a single quantum well dimension, which have low chemical stability as they tend to evolve to a mixture of quantum wells with different lead halide thicknesses and even to 3D material. The preparation of highly (photo)chemical and colloidal stable hybrid LHP nanosheets of m lateral size and 2.5 nm in height with a deep blue emission will be presented. The strategy of stabilizing the colloids for more than 8 h, storing them in the solid state for more than one year, and recovering the blue emissive colloid from the solid as needed will be discussed. References [1] [2] a) J. Song, L. Xu , J. Li , J. Xue , Y. Dong , X. Li , H. Zeng, Advanced Materials 2016, 28, 4861–4869. b) S. Gonzalez-Carrero, G. M. Espallargas, R. E. Galian, J. Pérez-Prieto, Journal of Materials Chemistry A 2015, 3, 14039-14045. c) M. C. Weidman, A. J. Goodman, W. A. Tisdale, Chemistry of Materials 2017, 29, 5019-5030. [3] C. C. Stoumpos, D. H. Cao, D. J. Clark, J. Young, J. M. Rondinelli, J. I. Jang, J. T. Hupp, M. G. Kanatzidis, Chemistry Matererials 2016, 28, 2852−2867. Acknowledgments. The work was supported by Ministerio de Economía, Industria y Competitividad (CTQ2017-82711-P, PID2020-115710GB, co-financed by FEDER; FPU17/ 05564, IRP), Ministerio de Ciencia e Innovación (Unit of Excellence “Maria de Maeztu” CEX2019-000919-M), and Generalitat Valenciana (IDIFEDER/2018/064 and PROMETEO/2019/080, GRISOLIAP/2019/041, RCT),c o-financed by FEDER).

Authors : Markus W. Heindl (1), Natalie Fehn (2), Lissa Eyre (1), Ian D. Sharp (1), Aras Kartouzian (2), G. Kieslich (3), Felix Deschler (1)
Affiliations : (1) Walter Schottky Institute & Department of Physics , Technical University of Munich, Garching, Germany (2) Department of Chemistry & Catalysis Research Center, Technical University of Munich, 85748 Garching, Germany (3) Department of Chemistry, Technical University of Munich, 85748 Garching, Germany

Resume : Chirality in semiconductor materials enables a number of powerful applications, reaching from consumer electronics and 3D displays to drug screening and encryption [1-3]. Lately, chiral hybrid perovskites have emerged as a promising class of materials for optoelectronic applications based on their ability to preferably absorb and emit one type of circularly polarized light. However, so far, the chiral organics used to introduce chirality into lead halide perovskites almost exclusively consist of a small group of commercially available, primary amines [1]. In nature, chirality is most prominently found in amino acids. These represent a diverse group of organic compounds whose application for industrial production is highly desirable as they are non-toxic, biodegradable and are available in large quantities at relatively low cost. We now introduce the chiral small organic 3-aminobutyric acid into the 1D perovskite dimethylammonium lead iodide (DMAPbI3) using a simple spin coating based approach. We find that the resulting material displays strong circular dichroism in the blue spectral region that is tunable in strength by adjusting the amount of amino acid introduced. We resolve the detailed structural origin of the chirality from single-crystal XRD experiments of the crystal structure. We employ transient optical spectroscopy to investigate the dynamics of excited state polarization and decay. Our findings expand the pool of chiral hybrid materials and provide fresh impulses for future maximization of chiral effects in hybrid perovskite materials. [1] G. Long, R. Sabatini, M. I. Saidaminov, G. Lakhwani, A. Rasmita, X. Liu, E. H. Sargent, W. Gao Chiral-perovskite optoelectronics. Nat. Rev. Mater. 5, 423?439 (2020). [2] B. Thaom, X. Gao, K. Pan, J. Deng Chiral Helical Polymer/Perovskite Hybrid Nanofibers with Intense Circularly Polarized Luminescence. ACS Nano 15, 7463-7471 (2021). [3] C. Chen, L. Gao, W. Gao, C. Ge, X. Du, Z. Li, Y. Yang, G. Niu, J. Tang Circularly polarized light detection using chiral hybrid perovskite Nat. Comm. 10, 1927 (2019).

Authors : Eve M. Mozur, James R. Neilson
Affiliations : Colorado State University

Resume : Hybrid halide perovskite semiconductors exhibit nearly ideal properties for myriad optoelectronic applications, including photovoltaics, light emission, and radiation detection. Curiously, these properties coexist with complex, organic cation-derived dynamic disorder and extensive chemical substitution. Furthermore, it appears that both dynamics and substitution enable and improve the functional performance. Neutron scattering and nuclear spectroscopy studies of these materials have yielded significant insight to the nature of the organic cation dynamics and how these dynamics are impacted by chemical substitution. In methylammonium-based materials, substitution tends to impede dynamics, thus resulting in orientational glass behavior. While substitution disrupts cooperative phase transitions in formamidinium-based materials, substitution preserves the local behavior of formamidinium. The retained dynamics and polarizability is advantageous for screening charged defects and myriad other behaviors thought to be responsible for the potentially transformative behavior of these solution-processable, high-performance materials. The dynamic degrees of freedom of the hybrid halide perovskites provide additional opportunities for application engineering and innovation not found in conventional compound semiconductors.

Authors : Angelica Simbula, Riccardo Pau, Liu Fang, Stefano Lai, Alessandra Geddo-Lehmann, Alessio Filippetti, Daniela Marongiu, Francesco Quochi, Michele Saba, Andrea Mura and Giovanni Bongiovanni
Affiliations : Dipartimento di Fisica, Università di Cagliari, ITALY

Resume : One of the main goals for perovskite materials is to approach ideal efficiency limits in solar cells or LEDs: being the radiative decay of optical excitations unavoidable, this can be done by reducing contributions from traps and defects. Despite all the advances in device performances, the bimolecular radiative recombination rate in metal halide perovskites is still not clearly established: coefficients derived under different assumptions can take very different values, and a lively debate is going on trying to conjugate their exceptionally long excitation lifetimes with large optical absorption coefficients. Here we provide a calibrated radiometric measurement of the instantaneous photoluminescence flux emitted by thin-films of hybrid perovskites with controlled carrier density under pulsed excitation. In all the analysed samples we uncover a radiative recombination rate much lower than the bimolecular recombination coefficient, revealing the presence of non-radiative bimolecular recombination rate that can be attributed to a population of dark states. Our findings suggest that to minimize unwanted decay channels for optical excitations one should also take account of this non-radiative contribution to the bimolecular decay, that is due to extrinsic effects, like trapping and defects, and can be substantially reduced with materials optimization.

Authors : Alexander S. Urban
Affiliations : Nanospectroscopy Group, Department of Physics, Ludwig-Maximilians-Universität München

Resume : Halide perovskite nanocrystals (NCs) have emerged as an intriguing material for optoelectronic applications, most notably for light-emitting diodes (LEDs), lasers, and solar cells. Their emission wavelength can be tuned with material composition and size as well as dimensionality, as in the case of two-dimensional (2D) nanoplatelets (NPls). These colloidal quantum wells have additional appeal for light emission, as the one-dimensional quantum confinement enhances their radiative rates and enables directional outcoupling. On top of this, due to a monolayer-precise control over their thickness, they constitute an intriguing system for spectroscopic studies on their fundamental optical, phononic, and energetic properties. In this talk, I will explore the recent results on halide perovskite nanoplatelets, including their synthesis. I will focus on their interesting excitonic properties, as these govern the interaction significant in light-emitting applications. Presenting the newest insights gained from optical spectroscopy and theoretical modeling, I will conclude by showing how these intriguing nanocrystals can be integrated into optoelectronic devices.

Authors : Elke Debroye, Hai I. Wang, Maarten B. J. Roeffaers, Mischa Bonn, Johan Hofkens
Affiliations : Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany

Resume : Metal halide perovskites have drawn increasing attention as photodetector materials due to their strong light absorption and resulting photocurrent.[1] More specifically, the sensitive detection of X-rays embodies an important research area, being motivated by a common desire to minimize the radiation doses required for X-ray imaging. In addition to lead-based perovskites, the lead-free double perovskite Cs2AgBiBr6 system has gained significant attention for photodetection due to the facile processing in combination with outstanding properties, such as high X-ray sensitivity,[2] high carrier mobility, and high stability. We aim to detail the dynamics and transport of the photogenerated charges that govern the photoresponse, relying on a set of high-resolution structural and optical spectroscopic tools.[3,4] Moreover, we demonstrate the importance of manipulating the perovskites’ microchemistry and intrinsic charge carrier dynamics to enhance the photoresponse toward an improved material platform for next-generation imaging.[5] Ultimately, to integrate perovskites in practical devices, controlled deposition and patterning is a critical step. We demonstrate the development of an all-evaporated structure or a dry lift-off process to fabricate air-stable perovskite photodetector arrays on both glass and flexible substrates, with a pixel resolution down to 5 μm.[6,7] 1. Clinckemalie, L.; … Debroye, E. Challenges and opportunities for CsPbBr3 Perovskites in Low- and High-Energy Radiation Detection. ACS Energy Lett., 2021, 6, 1290, 10.1021/acsenergylett.1c00007 2. Steele, J. et al. Photophysical Pathways in Highly Sensitive Cs2AgBiBr6 Double Perovskite Single-Crystal X-Ray Detectors. Adv. Mater., 2018, 30, 46, 1804450, 10.1002/adma.201804450 3. Zhang, H.; Debroye, E. et al. Highly Mobile Large Polarons in Black Phase CsPbI3. ACS Energy Lett., 2021, 6, 2, 568, 10.1021/acsenergylett.0c02482 4. Zhang, H.; Debroye, E. et al. Highly Mobile Hot Holes in Cs2AgBiBr¬6 Double Perovskite. Submitted 5. Keshavarz, M.; Debroye, E. et al. Tuning the Structural and Optoelectronic Properties of Cs2AgBiBr6 Double Perovskite Single Crystals Through Alkali Metal Substitution. Adv. Mater., 2020, 32, 40, 2001878, 10.1002/ adma202001878 6. Pintor, I. et al. All-Evaporated, All-Inorganic CsPbI3 Perovskite-based Devices for Broadband Photodetector and Solar Cell Applications. ACS Appl. Electron. Mater., 2021, 10.1021/acsaelm.1c00252 7. Xia, B. et al. Flexible Metal Halide Perovskite Photodetector Arrays via Photolithography and Dry Lift-off Patterning. Submitted

Authors : Sugato Hajra* (1), Manisha Sahu (1), Hoe Joon Kim (1)
Affiliations : (1) Daegu Gyeongbuk Institute of Science and Technology, Republic of Korea

Resume : The communication technology during the back centuries used the Morse code for transmitting coded signals. In late 1800, the message was transmitted in an efficient speed manner with help of Morse code communication from one area to another was delivered via telegraph wires where the dots and dashes combination would serve as each alphabet or number. The triboelectric nanogenerator is a widely preferred energy harvesting device that allows a wide variety of material selection, cheap fabrication, and low-frequency operation. The main advantages of this work are to eradicate the use of battery which have low life cycles and create an abundance of waste pollution. The nanogenerators could be a sustainable power source contributing its role to solve the partial energy crisis. Sr3CO2WO9 (SCWO) is synthesized by an aqueous sol-gel reaction. The cubic symmetry and Fm-3m space group of SCWO are shown by XRD analysis. The microstructure of PDMS-SCWO particles confirms the particles are distributed all over the PDMS. Triboelectrification is a phenomenon in which two materials bearing different polarity either rub or due to friction could accept or donate electrons leading to the generation of electrical output. These particles have a high dielectric constant and low loss make triple perovskite a promising candidate for TENG. A vertical contact separation triboelectric nanogenerator could produce voltage and current of 300 V and 2.2 ?A for 10 wt% polydimethylsiloxane ? Sr3Co2WO9 (PDMS-SCWO) composite film. The power density of the rough surface TP-TENG was 30.5 ?W/cm2, which is many times enhancement as compared to the power density of 5.5 ?W/cm2 of plain surface TP-TENG. Furthermore, the output is stable for TP-TENG making it a potential candidate for information signaling (Morse code) in real-time applications.

17:00 Q&A live session    
Authors : Boyer, D.*, Valleix, R., Cordonnier, A., Mahiou, R. and Chadeyron, G.
Affiliations : Université Clermont Auvergne, CNRS, Clermont Auvergne INP, ICCF, F-63000 Clermont-Ferrand, France.

Resume : During the last decade, the demand in nanophosphors has dramatically increased for addressing the requirements needed for several applications. In particular, nanosized phosphors with efficient optical properties have attracted much attention since they can be used in high-performance displays as well as fluorescent probes in nanomedicine or for specific shaping such as 3D printing with ink-jet techniques. Two distinct approaches can be considered for their design, the bottom-up (assembly from molecules) or the top-down strategies (size reduction to nanoscale). In this talk, I will illustrate both approaches for synthesizing several types of nanosized phosphors, i.e. inorganic (oxide and fluoride), organic-inorganic hybrids (organic dye encapsulated into silica nanoparticles) and semi-conductor nanocrystals (Quantum Dots or QDs). In particular, the preparation of Y3Al5O12:Ce3+ and NaYF4:Yb3+,Tm3+ nanoparticles and their implementation as respectively yellow-emitting phosphor for LED devices based on microLEDs (LED) and up-converting phosphor in the infrared range for medical imaging will be discussed. Furthermore, the development of luminescent hybrid nanoparticles composed of fluorescein entrapped into silica matrix by reverse microemulsion method will be presented. Finally, the last part will be devoted to a family of Cd-free QDs, constituted of InP cores coated with a ZnS shell, which are of great interest due to the size dependence of their outstanding optical properties.

Authors : N. Enea12, V. Ion1, N. D. Scarisoreanu1
Affiliations : 1Fotoplasmat center (C400), National Institute for Laser, Plasma and Radiation Physics, Magurele, Bucharest, Romania 2Faculty of Physics, University of Bucharest, 077125 Magurele, Romania

Resume : The quest for revealing new or improved functionalities in ferroelectric materials is at its peak nowadays. The new non-lead ferroelectric thin films were intensively developed in last years for application in the field of optics, electronics, sensing or harvesting solar energy. In this work we present the proprieties of different class of ferroelectric thin films, with different crystalline structures, obtained by Pulsed Laser Deposition (PLD) having tailored properties needed in photonics, electronics or sensing field. The use of PLD technique emphasizes the importance and the role of chemical pressure and epitaxial strain fine stoichiometric changes induced into the lead-free ferroelectrics as a result of either doping or of the lattice misfit between the lattice parameter of perovskites films and the used substrates on the enhancement of optical and electrical properties in thin films. The crystalline properties of the thin films thus obtained were studied using X-ray diffraction. The optical properties and the thicknesses of composing layers were investigated by spectroscopic ellipsometry (SE). Furthermore, the dependence of optical, electric and magnetic properties depending on temperature was determined. Acknowledgements: This work was supported by a grant of the Ministry of Research, Innovation and Digitization, CNCS/CCCDI ? UEFISCDI, project number PN-III-P4-ID-PCE-2020-2921, within PNCDI III

Authors : Tushar Debnath,1 Debalaya Sarker,2 He Huang,1 Zhong-Kang Han,2 Amrita Dey,1 Lakshminarayana Polavarapu,1 Sergey V. Levchenko,2 and Jochen Feldmann,1
Affiliations : 1 Chair for Photonics and Optoelectronics, Nano-Institute Munich, Physics Department, Ludwig Maximilians-Universität (LMU), Königinstr. 10, 80539 Munich, Germany 2 Center for Energy Science and Technology, Skolkovo Institute of Science and Technology, Moscow 143026, Russia

Resume : Organic-inorganic halide perovskite nanocrystals (PNCs) are gaining increasing attention in contemporary research due to their promising performance in light-emitting as well as solar technology. Photoexcitation of these PNCs with an ultrashort laser pulse can produce coherent phonons along the lattice displacement coordinate, leading to lattice vibrations. Here, we employ femtosecond pump-probe spectroscopy to initiate the photophysics by the formation of coherent phonons and to observe the subsequent coherent vibrational dynamics of formamidinium lead halide (FAPbX3, X=Br, I) PNCs.[1] We find that the FAPbX3 PNCs generate halide-dependent coherent vibronic wave packets upon non-resonant excitation, and the dominant contributions are attributed to the Pb–X bending and stretching modes of PbX64- octahedral units of the lattice. More importantly, for the first time, we observe higher harmonic vibrational modes in FAPbI3 PNCs, which points to a more anharmonic potential energy surface in the case of FAPbI3 as compared to FAPbBr3 PNCs. This is likely due to the weaker interaction between the central FA moiety (which sits in a larger octahedral interstitial site) and the inorganic cage for FAPbI3 PNCs, and thus the PbI64- unit can vibrate more freely. This weakening reveals the intrinsic anharmonicity in the Pb-I framework, and thus facilitating the energy transfer into overtone and combination bands. Furthermore, our control experiment with MAPbBr3 reveals the energy transfer between framework phonons due to the intrinsic anharmonicity of the lead-halide framework is indeed influenced by the interaction between the framework and the organic molecules, and not only by the halide nature. The insights interestingly not only unravel the underlying reason for the halide-dependent stability of these materials but also shed light on their charge-carrier mobility and light emission properties. References [1] T. Debnath, D. Sarker, H.Huang, et al. Nat. Commun. 12 (1), 2629 (2021).

Authors : I. Konidakis*, K. Brintakis, A. Kostopoulou, I. Demeridou, P. Kavatzikidou, and E. Stratakis
Affiliations : Institute of Electronic Structure and Laser (IESL) Foundation for Research and Technology-Hellas (FORTH) Heraklion-Crete, Greece

Resume : Due to their exceptional optoelectronic properties, all-inorganic lead halide perovskites offer enormous potential for next generation photonic, light-emitting, and optoelectronic devices. However, their usage is significantly limited by their poor stability upon moisture exposure and lead toxicity issues. Moreover, it has been recognized that the development of confined perovskite micro-patterns of various shapes and periodicities is essential towards expanding the application range. Herein we report a simple, low-temperature, post-glass melting encapsulation method that enables the controlled incorporation of highly photoluminescent cesium lead bromide perovskite nanocrystals within silver phosphate glass (AgPO3). Such host glass is transparent in most of the visible range, thus allowing full exploitation of the developed composite glasses towards optoelectronic and photonic devices. The reported fabrication protocol relies on a simple melting encapsulation process in which pre-synthesized perovskite crystals are inserted in the glass matrix, following the initial glass quenching. Based on this novel approach, two types of composite perovskite glasses are prepared, one that hosts perovskite isles and the second in which thin perovskite layers of few nm are embedded beneath the glass surface. Both types of composite glasses exhibit remarkable photoluminescence stability when compared to the ambient air-exposed perovskite crystals. More importantly, by means of a simple and fast cw-laser processing technique, we demonstrate the development of encapsulated dotted perovskite micropatterns within the composite perovskite glass. The ability of the proposed system to resolve stability and lead toxicity issues, coupled with the facile formation of encapsulated highly luminescent perovskite patterns pave the way towards the broad exploitation of perovskite crystals in various photonic applications.

18:30 Q&A live session    
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Session 07- 1D Nanostructures: Growth & Applications : D. Janas, Y. K. Mishra
Authors : Barbara Fazio
Affiliations : CNR-IPCF: Institute for Physical and Chemical Processes (IPCF) of the Italian National Research Council (CNR)

Resume : The development of highly functional materials for light emission and/or amplification is a research field in constant expansion; in particular, high-density semiconductor nanowires slabs represent promising systems attracting a considerable scientific interest for applications in light sources, sensing and photovoltaic devices [1]. The spatial arrangement of nanowires in new disordered textures can drive exciting optical phenomena. This is because their very multiple scattering nature and the light transport properties allow optical performances often superior to those offered by ordered photonic structures [2]. On the other hand, the diffusive propagation of light through these disordered materials gives rise to fascinating and unexpected interference phenomena surviving also in the inelastic scattering regime [3]. Here we will present recent experimental results where disordered arrays of silicon nanowires are used to generate and beam directional coherent Raman light [4]. We show the direct visualization of the weakly localized Raman radiation by both real- and momentum-space microscopy, that permitted us to gain insight on the mechanisms ruling the light transport through the random media. These results pave the way for the development of next generation of new light sources based on both the coherent control of directional beaming and the fine frequency tuning. References: [1] Priolo F. et al., Nat. Nanotech. 9, 19 (2014) [2] B. Fazio, P. Artoni, M.A. Iatì, C. D'Andrea, M.J. Lo Faro, S. Del Sorbo, S. Pirotta, P.G. Gucciardi, P. Musumeci, C.S. Vasi, R. Saija, M. Galli, F. Priolo, and A. Irrera. Strongly Enhanced Light Trapping in a Two-dimensional Silicon Nanowire Random Fractal Array. Light: Science & Applications,5: e16062, 2016. [3] B. Fazio, A. Irrera, S. Pirotta, C. D’Andrea, S. Del Sorbo, M.J. Lo Faro, P.G. Gucciardi, M.A. Iatì, R. Saija, M.Patrini, P. Musumeci, C.S. Vasi, D.S. Wiersma, M. Galli, and F. Priolo. Coherent Backscattering of Raman Light. Nature Photonics 11: 170-176, 2017. [4] M.J. Lo Faro, G. Ruello, A.A. Leonardi, D. Morganti, A. Irrera, F. Priolo, S. Gigan, G. Volpe, and B. Fazio. Visualization of directional beaming of weakly localized Raman from a random network of silicon nanowires. Advanced Science, 2100139, 1-11, 2021. DOI 10.1002/advs.202100139.

Authors : Claire Goldmann, Marta de Frutos, Eric H. Hill, Doru Constantin, Cyrille Hamon
Affiliations : Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France. Institute of Physical Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany.

Resume : Wet chemical synthesis is a very versatile method to obtain Au and Ag particles with an astonishing shape diversity, largely through the use of various additives, each of them fulfilling one or several roles. In this framework, I will focus on bimetallic Au/Ag nanoparticles, whose properties are rendered even more diverse by the combination of the two constituents. For instance, depositing Ag on pentatwinned Au bipyramids (AuBPs) is an efficient way to form Ag nanorods (AgNRs) with controllable aspect ratio which can be increased significantly upon controlled Ag addition, shifting LSPR from the visible to the infrared region. In a first work, we have shown an unexpected double role of ascorbic acid in this synthesis by using a combination of time resolved techniques.(1) AgNRs were prepared in which the gold bipyramid was located at the center of mass of the NPs. In a recent work, we developed a method in mixed solvent to break the inversion symmetry of the AgNRs by displacing the seed position at one tip of the AgNR. We propose a mechanism to understand the Ag deposition on the gold surface which is supported by experimental evidence and molecular dynamic (MD) simulations.(2) 1. Aliyah, K.; Lyu, J.; Goldmann, C.; Bizien, T.; Hamon, C.; Alloyeau, D.; Constantin, D., J. Phys. Chem. Lett. 2020, 11 (8), 2830-2837. 2. Goldmann, C.; de Frutos, M; Hill, E.; Constantin, D.; Hamon, C., Chem. Mater. 2021, ASAP

Authors : Francis Leonard Deepak 1,*, Junjie Li 1,2
Affiliations : 1 Nanostructured Materials Group, International Iberian Nanotechnology Laboratory (INL), Avenida Mestre Jose Veiga, Braga 4715-330, Portugal. E-mail: 2 CAS Key Laboratory of Functional Materials and Devices for Special Environments, Xinjiang Technical Institute of Physics & Chemistry, CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011, China.

Resume : Sub-10 nm quasi-one dimensional (1D) nanostructures have received increasing interest for their use as small basic building units in nanodevices. One dimensional Silver (Ag) nanostructures, as one of the promising candidates for electronics, plasmonics and sensing applications, have been fabricated by a variety of chemical and physical strategies. However, preparing sub-10 nm (diameter) 1D Ag nanostructures for nanofabrication remains challenging experimentally and the nucleation and growth dynamics of the Ag nanowires are still not fully understood (1-4). In this work, we report the segregation-driven in situ generation of Ag NWs on the surface of a Ag2WO4 (AWO) nanorod (NR) under electron beam irradiation in an aberration corrected-TEM (AC-TEM). We adopted AWO as the starting material because previous studies have demonstrated Ag surface segregation and the formation of Ag NPs on the oxide support under plasma or electron beam irradiation (5-7). By controlling the electron irradiation dose rate, sub-10 nm Ag NWs (9.5 ± 0.2 nm) are fabricated on the oxide surface. The generated Ag NWs show a tunable length/diameter aspect ratio, and the formed surface in the NWs is the low-energy {111} plane. The direct in situ observations on the nucleation and growth dynamics uncover that the sub-10 nm silver NWs show a combined growth process of linear first-order kinetics and nonlinear second order kinetics in the lateral direction and the electron dose rate plays an important role in regulating the diameter of the supported Ag NWs (8). The ability to fabricate Ag NWs in a controllable way by using electron beam irradiation represents a significant step forward to the further applications of Ag NWs in nanodevices. The present study opens a new avenue for the fabrication of sup-ported sub-10 nm Ag nanowires through an electron beam irradiation nanofabrication route and highlights the importance of irradiation dose- and dynamics controlled materials growth. References: 1. J. Li, et al., Nanoscale Horiz., 2019, 4, 1302–1309. 2. J. Li, Z. Wang and F. L. Deepak, ACS Nano, 2017, 11, 5590–5597. 3. J. Li, et al., Adv. Sci., 2018, 5, 1700992. 4. J. Li, et al., J. Phys. Chem. Lett., 2018, 9, 961–969 5. J. Li, Z. Wang, Y. Li and F. L. Deepak, Adv. Sci., 2019, 6, 1802131. 6. M. d. Assis, et al., Sci. Rep., 2019, 9, 9927. 7. R. A. Roca, et al., Inorg. Chem., 2016, 55, 8661–8671. 8. Junjie Li and Francis Leonard Deepak, Chem. Commun., 2020, 56, 4765.

Authors : Zahra Azimi, Hark Hoe Tan, Chennupati Jagadish, Jennifer Wong-Leung
Affiliations : Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia

Resume : The possibility of designing composite Gallium-Arsenide (GaAs) nanowires structures via bottom-up methods has attracted significant interest for the engineering of future optoelectronic devices [1]. The crystal structure and the stacking fault density of GaAs nanowires largely determine their optoelectronic properties [2]. Here, we present an investigation of the structural and optical properties of GaAs nanowires. GaAs nanowires were grown by metal-organic vapour phase epitaxy (MOCVD) on GaAs (111)B substrates initially patterned using selected area epitaxy (SAE). Transmission electron microscopy (TEM) shows that GaAs nanowires have a ZB structure with a varying twin defect density (TDs) along the nanowire’s length. The average local twin defect density (ntdd), computed for a section length of 1 µm along the NW’s axis, decreases from 110 to 13 #/µm from the base to the tip of the NW. To correlate the GaAs NW crystal structure to its electronic band structure, cathodoluminescence (CL) and time resolved photoluminescence measurements were done at room temperature. The CL intensity increases by 14 times from the bottom to the NW’s tip, while the CL peak position shifted from 897 nm (1.382 eV) to 886 nm (1.399 eV). The CL peaks red-shift along the NWs vertical axis is tentatively attributed to type-II band alignment at the ZB-TD-ZB interfaces. The high surface recombination velocity of GaAs is a major issue for applications in optoelectronic devices. As a result, passivation of the nanowire surface is required for various applications such as lasing. Here, however, we demonstrate that when sufficient nanowire’s length and optimal structural properties are obtained, pure unpassivated GaAs nanowires can achieve low-temperature lasing. This provides insights towards the engineering of GaAs NW for applications in optoelectronic devices. [1] H. Li, Y. Chen, Z. Wei, and R. Chen, ‘Optical property and lasing of GaAs-based nanowires’, Sci. China Mater., vol. 63, no. 8, pp. 1364–1381, 2020. [2] M. Heiss et al., ‘Direct correlation of crystal structure and optical properties in wurtzite/zinc-blende GaAs nanowire heterostructures’, Phys. Rev. B - Condens. Matter Mater. Phys., vol. 83, no. 4, pp. 1–10, 2011.

Authors : Mohammed Zeghouane 1, Hadi Hijazi 2, Pascal Gentile 3, Franck Bassani 1 and Bassem Salem 1
Affiliations : 1 Univ. Grenoble Alpes CNRS, CEA/LETI Minatec, LTM, 38054 Grenoble, France 2 Faculty of Physics, St. Petersburg State University, Universitetskaya Emb. 13B, 199034, St. Petersburg, Russia 3 Univ. Grenoble Alpes, CEA, IRIG-DEPHY, PHELIQS/SINAPS, F-38054 Grenoble, France

Resume : GeSn alloy is the most interesting binary material within group IV-based semiconductor family which opens up a possibility for achieving direct bandgap at typical values of Sn ranging from ~ 6 –11%. Unfortunately, increasing the Sn composition in solid GeSn remains a challenging task due to the miscibility gap at typical growth temperatures, lattice mismatch issues and Sn segregation. Nanowires (NWs) exhibit great properties such as efficient strain relieving capability and excellent crystalline quality. That is why GeSn NW grown by different techniques have recently gained much attention. However, even in NWs one should compromise between the increased Sn composition and the spatial homogeneity along the GeSn NW crystal. The most commonly used method to grow NWs with a high degree of crystal quality is the Vapor-Liquid-Solid (VLS) mechanism. It is shown that the composition of a catalyst droplet influences many properties of VLS semiconductor NWs, including their crystal phase, doping, growth rate, chemical composition, growth direction and morphology. This presentation will focus on a comprehensive study of VLS-CVD grown GeSn nanowires with different catalyst droplets composition, combining the growth technology, complementary chemical and structural analyses and theoretical modeling. The influence of growth conditions such as temperature, vapor phase composition and liquid phase composition on the crystallization rate of both Ge and Sn from the liquid to the solid phase will be discussed. The end result shows that Sn incorporation with a high degree of homogeneity along the NW can be improved by adding some specific foreign elements in the liquid droplet. This is achieved by understanding the kinetics and the thermodynamic in the liquid phase, and coupling them with the kinetically controlled composition of solid nanowires. Overall, these findings provide a convenient method to control the composition and the homogeneity of GeSn NWs by adding suitable foreign atoms to the catalyst droplets and this pave new ways for fabrication of cheap and highly efficient nano- and opto- electronic devices on Si electronic platform.

Authors : G. Mineo1,2; K. Moulaee 3; G. Neri 3; S. Mirabella1,2; E. Bruno1,2;
Affiliations : 1 Dipartimento di Fisica e Astronomia ?Ettore Majorana?, Università di Catania, via S. Sofia 64, 95123 Catania, Italy; 2 CNR-IMM, Università di Catania, via S. Sofia 64, 95123 Catania, Italy; 3 Dipartimento di Ingegneria, Università degli studi di Messina, Contrada Di Dio, 98158, Sant'Agata, Messina, Italy;

Resume : Nanostructured WO3 represents a promising material for the realization of fast and reliable H2 sensors based on chemoresistive effect, even if the mechanism regulating the interaction between WO3 and H2 is not completely understood. A simple and low-cost technique to get well controlled WO3 nanorods would represent a key element for H-related applications. A powder of WO3 nanorods (400 nm long, 5 nm large) is produced by hydrothermal technique and drop casted onto Pt interdigitated electrode. XRD analysis confirms hexagonal crystal structure. The chemoresistive behaviour is investigated in the 250-400°C temperature range and for 2000-50000 ppm of H2 concentrations and the measured response transients have been successfully modelled within the Langmuir theory by hypothesizing two independent active processes: a fast process (below 4 s) which is attributed to interaction with adsorbed oxygen at WO3 nanorods surface and a slower process (20-1000 s) which occurs through oxygen vacancies generation in bulk WO3 [1]. H intercalation in WO3 is ruled out. The chemoresistive effect leading to H2 sensing by WO3 is explained through the above processes, whose kinetic barriers have been quantified. These data open the route for development of fast, sensitive and low-temperature operating H2 sensor based on WO3. [1] G. Mineo, K. Moulaee, G. Neri, S. Mirabella, E. Bruno, H2 detection mechanism in chemoresistive sensor based on low-cost synthesized WO3 nanorods (submitted to Sensor and Actuators B: Chemicals)

09:45 Q&A live session    
Session 08- QDs - Nanoparticles: Growth & Applications : J. Adam, R. Puglisi, Y. K. Mishra
Authors : Riporto, F.*(1), Bredillet, K.(1), Beauquis, S.(1), Le Dantec, R.(1), Monnier, V.(2) & Mugnier, Y.(1).
Affiliations : (1) SYMME, University of Savoie Mont Blanc, F-74000 Annecy, France (2) Institut des Nanotechnologies de Lyon (INL), UMR CNRS 5270, École Centrale de Lyon, Université de Lyon, F-69134 Écully CEDEX, France

Resume : Recent detailed investigations of the formation mechanisms of centrosymmetric metal oxide nanoparticles such as TiO2 and ZrxTi1-xO2 have evidenced the appearance of oxo-alkoxy clusters that further aggregate into amorphous nuclei at low hydrolysis rates of alkoxide precursors [1?3]. In this work, a mixture of LiOEt and Nb2(OC2H5)10 diluted in alcohols and glycols of different chain lengths has been used to produce non-centrosymmetric LiNbO3 nanocrystals. Upon hydrolysis of the initial precursor solutions kept under magnetic stirring, DLS measurements demonstrate the rapid formation of ~2nm oxo-clusters for each solvent after ligand exchange with the initial ethoxide precursors. After 24h at room temperature and formation of a viscous clear gel, SAXS measurements confirm the presence of ?amorphous? nuclei of average diameter ~4nm. A solvothermal treatment at 235°C for 24h then results in the formation of LiNbO3 nanocrystals whose average crystallite size continuously decreases from 24 to 15 nm when the chain length of the co-solvent is increased from ethanol to heptanol. Time- and temperature-dependent experiments of the solvothermal treatment also reveal the presence of a not yet-identified, crystallized reaction intermediate. Finally, colloidal suspensions of Er-doped and Er-Yb co-doped nanocrystals evidence scattering of several nonlinear optical (SHG, THG and SFG) and up-conversion (UC) signals.

Authors : Raja S.R. Gajjela1, Arthur L. Hendriks1, James O. Douglas2, Elisa M. Sala3,4, Peter Steindl5,6, Peter Klenovsky`5,7, Paul A.J. Bagot2, Michael P. Moody2, Dieter Bimberg3,8, and Paul M. Koenraad1
Affiliations : 1-Department of Applied Physics, Eindhoven University of Technology, Eindhoven 5612 AZ, The Netherlands 2-Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK 3-Center for Nanophotonics, Institute for Solid State Physics, Technische Universita ̈t Berlin, Hardenbergstr. 36, 10623 Berlin, Germany 4-EPSRC National Epitaxy Facility, The University of Sheffield, North Campus, Broad Lane, S3 7HQ Sheffield, United Kingdom 5-Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 267/2, 61137 Brno, Czech Republic 6-Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, Netherlands 7-Czech Metrology Institute, Okružní 31, 63800 Brno, Czech Republic 8-“Bimberg Chinese-German Center for Green Photonics” Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences at CIOMP, 13033 Changchun, China

Resume : Sb-based quantum dots with large, single-hole confinement are promising candidates for quantum dot flash memories. We analyzed the size, shape, and composition of highly strained (InGa)(AsSb) Stranski-Krastanov quantum dots (SKQDs) embedded in a GaP matrix with atomic resolution by cross-sectional scanning tunneling microscopy (X-STM) and atom probe tomography. The sample investigated in this work is exactly the same as the one with a storage time record for metal-organic chemical vapor deposition (MOCVD) grown heterostructures of 1 hr at room temperature, measured via deep-level transient spectroscopy. These quantum dots have a truncated pyramid shape with a base length of 8.5 nm and a height of 3 nm. The core of the QD is uniform with no alloy fluctuations but intermixing is observed close to the QD edges. The QDs occur at a very high density of ~4×10^11 cm^-2 compared to conventional InAs SKQDs. Finite element (FE) simulations are performed, using structural data from X-STM, to calculate the strain and the outward relaxation of the cleaved QDs. FE simulations together with X-STM results are used to estimate the composition of the QDs i.e., ∼In0.3Ga0.7As0.85Sb0.15. A similar ratio of 2:1-In:Sb was observed from atom probe experiments, which is in good agreement with FE simulations, and previous optical, electrical, and theoretical studies. The results prove that the InGaSb and GaAs layers have strongly intermixed during the QD formation. A detailed analysis of the capping layer is performed showing the segregation of Sb and In atoms from the QD layer into the capping layer. Overall, the current study provides a detailed structural and compositional overview of these novel QDs, shedding light on the Sb incorporation into the QD-layer and provides valuable feedback to the MOCVD growth of Sb-based QDs, to optimize the storage time of QD-Flash memory devices.

Authors : Rodolphe Valleix Federico Cisnetti Hanako Okuno Philippe Boutinaud Geneviève Chadeyron Damien Boyer
Affiliations : Rodolphe Valleix, Dr. Federico Cisnetti, Pr. Philippe Boutinaud, Pr. Geneviève Chadeyron, Dr. Damien Boyer: Université Clermont Auvergne, CNRS, Clermont Auvergne INP, ICCF, F-63000 Clermont-Ferrand, France Dr. Hanako Okuno: Université Grenoble Alpes, CEA, IRIG-MEM, 38000 Grenoble, France

Resume : In the race for miniaturization of optical systems like lighting or display devices, the development of luminescent nanoparticles with high quantum yields and covering a wide colour-range represents a crucial issue. Colloidal quantum Dots (QDs) seem to meet all the requirements for such applications. QDs have generally a diameter lower than 10 nm and exhibit size-tunable optical properties. Nowadays, in lighting and display technologies, QDs exhibiting the best stability under continuous irradiation (UV) and the highest optical performances contain cadmium, a strongly toxic and RoHS[1]-prohibited chemical element. The purpose of the present work is to develop a Cd-free family of QDs through the very popular hot-injection method allowing fine control of stoichiometry, size and size distribution of the nanocrystals. To this end, we have synthesized indium phosphide (InP) QDs from indium halides and aminophosphine precursors. [2] We have identified a specific diamine yielding tetrahedral QDs with adjustable edge lengths from ~ 3 to 6 nm, as confirmed by UV/Visible spectroscopy and dark field transmission electron microscopy. The underlying mechanisms are clarified by combining 31P liquid NMR and UV/Visible spectroscopies. After coating with a ZnS shell, the InP/ZnS QDs demonstrate fluorescence from 480 to 620 nm with photoluminescence quantum yield (PLQY) in the 45 – 60 % range depending on the experimental conditions. [1] Restriction of hazardous substances in electrical and electronic equipment: European directive (2002/95/CE). [2] Tessier et al. Chem. Mater. 2015, 27, 4893-4898.

Authors : AM Lepadatu, C Palade, I. Dascalescu, A. Slav, I. Stavarache, A.V. Maraloiu, V.S. Teodorescu, T. Stoica, ML Ciurea
Affiliations : National Institute of Materials Physics, Atomistilor 405A, 077125, Magurele, Romania

Resume : Group IV quantum dots (QDs) are attractive for non-volatile memories considering compatibility with CMOS technology [1]. Here, we use alloy SiGeSn QDs as charge storage nodes with advantages of low thermal budget for formation, high stability (little Si to GeSn) and adjustable composition. Our approach for QDs-based non-volatile memory consists in magnetron sputtering of 3-layers stack of gate HfO2/intermediate SiGeSn-HfO2/tunnel HfO2 on Si wafer, followed by RTA for nanostructuring, meaning the formation of SiGeSn QDs in floating gate (FG) [2,3]. High-k dielectric HfO2 lends itself to non-volatile memories, being a standard material in semiconductor processing. So, we achieve the formation of ~5 nm Ge-rich SiGeSn QDs in FG with 5% Si content and diamond structure (high resolution transmission electron microscopy, Raman spectroscopy). SiGeSn QDs contain small amount of Sn (2%) in FG, while at the interface of FG with adjacent layers (gate and tunnel HfO2), Sn amount is much increased to 15%. This can be explained by Sn atoms diffusion and segregation to the FG interfaces taking into account that Sn presence favours SiGeSn crystallization process (decreasing crystallization temperature). The memory capacitors (Al contacts) present capacitance-voltage hysteresis loops with high frequency-independent memory window of 3–4 V produced by charge storage in SiGeSn QDs. [1] Z. Lv, Y. Wang, J. Chen, J. Wang, Y. Zhou, S.-T. Han, Chem Rev 120, 3941 (2020) [2] C. Palade, A. Slav, A.M. Lepadatu, I. Stavarache, I. Dascalescu, V.A. Maraloiu, C.C. Negrila, C. Logofatu, T. Stoica, V. Teodorescu, M.L. Ciurea, S. Lazanu, Nanotechnology 30, 365604 (2019) [3] C. Palade, A. Slav, A.-M. Lepadatu, A.V. Maraloiu, I. Dascalescu, S. Iftimie, S. Lazanu, M.L. Ciurea, T. Stoica, Appl Phys Lett 113, 213106 (2018)

Authors : AM Lepadatu, C Palade, A. Slav, I. Dascalescu, O. Cojocaru*, V.S. Teodorescu, T. Stoica, ML Ciurea
Affiliations : National Institute of Materials Physics, 405A Atomistilor Street, 077125 Magurele, Romania

Resume : The pathway adopted by our group for obtaining group IV-based quantum dots (QDs) / nanocrystals (NCs) for photonics applications is to embed QDs/NCs in oxide matrix [1,2]. This is achieved by magnetron sputtering for deposition of films/multilayers followed by rapid thermal annealing for nanostructuring. Strong quantum confinement effect in Ge NCs is enabled due to high 24 nm Bohr exciton radius, while by alloying Ge with small Si content, the thermally stability of NCs is increased due to diminished fast Ge diffusion. GeSi NCs/QDs represent a very advantageous alternative to III?V semiconductors for group IV photonics as they are CMOS compatible and eco-friendly, and their fabrication by magnetron sputtering is cost-effective and versatile. Here, we focus on Ge QDs and GeSi NCs in TiO2. We show that the sensitivity limit (in spectral photocurrent) is much extended in SWIR up to 1700 nm for GeSi NCs-TiO2 in comparison to 1250 nm for films of Ge NCs embedded in TiO2. The extended SWIR sensitivity is explained by the lower density of non-radiative recombination centers, as in GeSi NCs-TiO2 samples the photocarriers are generated in Ge-rich SiGe NCs stabilized by formation of a thin SiO2 layer at NC/matrix interface [1]. On the other hand, coplanar structures of Ge NCs-TiO2/ SiO2/Si substrate show enhanced photocurrent by field effect with exponential voltage increase due to induced carrier depleted zone [2]. [1] A.-M. Lepadatu, C. Palade, A. Slav, O. Cojocaru, V.A. Maraloiu, S. Iftimie, F. Comanescu, A. Dinescu, V.S. Teodorescu, T. Stoica, M.L. Ciurea, J Phys Chem C 124, 25043 (2020) [2] A.-M. Lepadatu, A. Slav, C. Palade, I. Dascalescu, M. Enculescu, S. Iftimie, S. Lazanu, V.S. Teodorescu, M.L. Ciurea, T. Stoica, Sci Rep 8, 4898 (2018)

15:15 Q&A live session    
Authors : Santanu Manna, Saimon Filipe Covre da Silva, Huiying Huang, Christian Schimpf, Barbara Lehner, Tobias Krieger, Armando Rastelli
Affiliations : Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Austria

Resume : Out of different kinds of solid-state qubits, quantum dot (QD), grown by molecular beam epitaxy (MBE), is a very promising one. Because of the possibility to interface Rb-atom for quantum memory, GaAs QD-emitted single photons, with high brightness and purity, at ~780 nm is highly demanding. On the other hand, achieving highly symmetric dot with a very low fine structure (<1 µeV) in order to generate entangled photons, droplet etching mediated GaAs QD is leading the way. Therefore, presently, GaAs QD is drawing attention of different research groups, even those working with entangled photons out of a nonlinear crystal via spontaneous parametric down conversion, either to use its high pure single photons or entangled photons or both. Here, I will describe about the different growth modes by MBE and novel droplet etching technique as a newer addition to this in order to obtain highly symmetric QDs and to provide a clear view on the difference compared to widely studied InAs QDs on GaAs. I will describe also an implementation of a Yagi-Uda dielectric antenna containing this GaAs QDs to extract more light from it with a privilege of non-deterministic positioning of QDs and different properties of this kind of antenna with a possibility to enhance its strength by surface engineering. I will present relevant optical simulations performed using Lumerical FDTD solutions for this antenna structure along with several other structures like distributed Bragg reflector cavity and bull’s eye cavity to make a comparison with respect to the Purcell enhancement, extraction efficiency, farfield pattern and fabrication challenges. In the end, I will describe about the present ongoing work for blinking free entangled photon source to employ in a quantum key distribution experiment. References 1. Huang H, Manna S*, Schimpf C, Reindl M, Yuan X, da Silva S F C, Rastelli A* (2021) Bright single photon emission from quantum dots embedded in a broadband planar optical antenna (*Corresponding authors). Advanced Optical Materials 9, 2001490 (1-8). 2. Schimpf C, Reindl M, Huber D, Lehner B, Da Silva S F C, Manna S, Vyvlecka M, Walther P, Rastelli A (2021) Quantum cryptography with highly entangled photons from semiconductor quantum dots. Science Advances 7, eabe8905 (1-8). 3. Manna S, Huang H, da Silva S F C, Schimpf C, Rota M B, Reindl M, Trotta R, Rastelli A (2020) Surface passivation and oxide encapsulation to improve optical properties of a single GaAs quantum dot close to the surface. Applied Surface Science 532, 147360 (1-7). 4. Gurioli M, Wang Z, Rastelli A, Kuroda T, Sanguinetti S (2019) Droplet epitaxy of semiconductor nanostructures for quantum photonic devices. Nature Materials 18, 799–810.

Authors : Hyeonbome Kim1*, SeungGyo Jeong2, Sung Ju hong3, Woo Seok Choi2, Dongseok Suh1
Affiliations : (1) Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea (2) Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea (3) Division of Science Education, Kangwon National University, Gangwon-do 243341, Republic of Korea

Resume : Resonant tunneling[RT] which is a quantum mechanical process has been attracting both scientific and technological attention because of its interesting physics and application for electronics. This phenomenon accompanies negative differential resistance in current-voltage characteristics and has various physical properties that are used in many electronic circuits such as multi-level logic devices. But oxide-based RT study encounters difficulty because of sample instability, crystal quality, and lack of evidence for a mechanism. Here shows negative differential resistance[NDR] by applying voltage and measuring current passing through the SRO/STO SL system. we deliberately designed SrRuO3/SrTiO3[SRO/STO] superlattice[SL]. Using the pulsed-laser deposition, we can control SRO/STO SL with an atomic-scale precision which results in a quantized state of SRO between the STO barrier. Due to the discrete state of the SRO, SRO/STO SL system show [NDR] when Fermi level match with the SRO energy state by applying voltage. Specifically, we changed the thicknesses of STO from 2 to 8-unit cell while that of SRO is fixed to check the evolution of RT. We expect this study opens a possibility of new applications based on the epitaxial thin film oxide.

Authors : L. Branzi1*, G. Lucchini2, E. Cattaruzza2, N. Pinna3, A. Benedetti1, A. Speghini2
Affiliations : 1Department of Molecular Sciences and Nanosystems, Ca’ Foscari University of Venice, Via Torino 155, Venezia Mestre, Italy. 2Nanomaterials Research Group, Department of Biotechnology and INSTM, RU Verona, University of Verona, Strada le Grazie 15, Verona, Italy. 3Institut für Chemie and IRIS Adlershof, Humboldt-Universität zu Berlin, BrookTaylor-Str. 2, 12489 Berlin, Germany.

Resume : Easy and green chemistry production of carbon dots (CDs) that exhibit a precise chirality has attracted great interest nowadays. Chiral nanomaterials are promising for potential applications in enantioselective catalysis, separation and others [1]. CDs can be produced directly by controlled decomposition of appropriate optical pure organic substrates via a bottom-up approach. In particular, aminoacids are among the most investigated classes of chiral starting materials. Cysteine-based chiral CDs have been already applied in several contests with promising performances [2,3]. For these reasons, we investigated a novel catalysed process for preparation of CDs, using Cu(II) ions; the process does not require any thermal treatment and the CDs formation is driven by the production of reactive radical species generated by the catalytic role of the multivalent transition metal [3]. Due to the mild reaction conditions, this synthetic process is particularly suitable for in situ and ex situ investigations. We focused our attention on the processes taking place during the formation of the CDs, with special attention to: 1) role of the metal ion in the decomposition process: the spectrophotometric analyses show direct evidence on the formation of a cysteine-Cu(II) complex that is active in the cysteine oxidation process leading to the generation of oxygen and sulfur radical active species (ROS and RSS); 2) role of the organic substrate structure: by investigating reactions conducted with different organic substrates whose thiyl radical chemistry is known, we recognized a non-trivial role of the radical hydrogen abstraction reactions involved in the formation process of CDs; 3) the evolution of the nanomaterial during the reaction course: this evolution is related to the decomposition of the grafted chiral molecules and the formation of luminophores species on the particle surface; 4) a detailed analysis on the evolution of optical chirality during the synthesis: we related the effects on the chiroptical signal to the formation mechanism of the nanomaterial revealing significant evidence on the chirality origin. Our investigation on this novel synthetic approach for the synthesis of chiral CDs with high control on optical and chiroptical properties paves the way for the design of new chiral nanosystems. [1] Z. Tang, Chiral Nanomaterials: Preparation, Properties and Application, Wiley-VCH, Weinheim, Germany, 1st edn, 2018. [2] L. Hu, et al. Nanoscale, 2018, 10, 2333–2340, 10.1039/C7NR08335A. [3] F. Li, et al. Ang. Chem. Int. Ed. 2020, 59, 11087-11092, 10.1002/anie.202002904. [3] L. Branzi et al. Nanoscale, 2021, 10.1039/D1NR01927A.

Authors : A. Sciortino, A. Panniello, G. Minervini, N. Mauro, G. Giammona, M. Cannas, M. Striccoli, F. Messina
Affiliations : Dipartimento di Fisica e Chimica – Emilio Segré, Università degli Studi di Palermo, Via Archirafi 36, 90123 Palermo (Italy); CNR-IPCF-Bari Division, Via Orabona 4, 70126 Bari, Italy; Polytechnic University of Bari, Via Edoardo Orabona, 4, 70126 Bari BA, Italy; e Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche, Università degli Studi di Palermo, Via Archirafi 32, 90123 Palermo (Italy); e Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche, Università degli Studi di Palermo, Via Archirafi 32, 90123 Palermo (Italy); CNR-IPCF-Bari Division, Via Orabona 4, 70126 Bari, Italy; Dipartimento di Fisica e Chimica – Emilio Segré, Università degli Studi di Palermo, Via Archirafi 36, 90123 Palermo (Italy); ;

Resume : Carbon Nanodots (CDs) are a family of carbon-based nanoparticles endowed with tunable visible fluorescence,1-2 which makes them very promising for light-emitting devices, optoelectronics, photocatalysis, and more. The technological use of CDs is hampered by the difficulty of controlling their optical response, and by a low emission efficiency in the orange-red spectral region, still insufficient for many applications. In fact, the synthesis of efficiently red-emitting CDs remains rare.3 We explored the interactions of CDs with metal nanoparticles (NPs), as a route to enhance their fluorescence. The electromagnetic response of Au and Ag NPs displays well-known plasmonic resonances due to collective oscillations of charge carriers. When these NPs interact with other nanomaterials, plasmonic effects can be used to control the optical response of the resulting coupled nanosystems.4 We devised a simple route to synthesize CD-AuNP hybrids by electrostatic self-assembly in colloidal phase. The spatial separation of CDs from AuNPs in the nano-hybrid can be regulated by a suitable choice of CD surface ligands. Depending on this, the interactions between CDs and AuNPs lead either to a quenching or to an enhancement of the orange fluorescence of CDs. In the right conditions, the plasmonic near-field of AuNPs can be exploited to enhance CD emission of a factor of six. A thorough analysis of CD-AuNP electronic interactions by steady-state, nanosecond and femtosecond time-resolved methods shows that CD fluorescence enhancement is due to ultrafast energy transfer from AuNPs plasmonic states. These findings provide insight on the interactions between metal NPs and fluorescent materials, and open a route to boost the optical response of CDs in the orange-red spectral range. 1 A. Sciortino et al. C 4, 67 (2018) 2 Z. Kang, S.-T. Lee Nanoscale 11, 19214 (2019) 3 K Holà et al. ACS Nano 2017, 11, 12402 4 N. Kholmicheva et al. Nanophotonics 8, 0143.

16:30 Q&A live session    
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Session 09- Carbon Nanostructures: Growth & Applications : D. Janas, Y. K. Mishra
Authors : Tomohiro Shiraki
Affiliations : 1 Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan 2 International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan E-mail:

Resume : Single-walled carbon nanotubes (SWCNTs) are one dimensional (1D) nanocylinders consisting of rolled-up single graphene with the diameter of ca. 1 nm and the length of a few hundred nm or ~micro meter.[1] The cylindrical structures are identified by chiral indices that determine their diameters and properties, such as metallic and semiconducting features. In SWCNTs, the effects of quantum confinement and weak dielectric screening strongly appear in Coulombic interactions for carriers, and, therefore, stable excitons (electron–hole bound states) even at room temperature are generated by photoexcitation and emit photoluminescence (PL) in near infrared (NIR) regions.[2] Local chemical functionalization of the SWCNTs has been found to enhance their NIR PL properties due to its defect doping effect.[3-6] In the locally functionalized SWCNTs (lf-SWCNTs), chemical bonding between modifier molecules and nanotube walls forms defects such as sp3 carbon in their crystalline sp2 carbon networks. As a result, the defect doped sites emit E11* PL that is red-shifted and bright compared to the original E11 PL from pristine SWCNTs. That is due to narrow bandgap formation and exciton trapping (localization) function by the functionalization-induced electronic structure changes at the doped sites. In particular, the functionalized molecules on the doped sites play important roles for the wavelength modulation of E11* PL from the lf-SWCNTs.[3,4] For example, our proximal defect doping approach using bis-aryldiazonium salts allows to create largely red-shifted PL (E11^2* PL) over 1250 nm-regions from the lf-SWCNTs with (6,5) chiral index.[7,8] Molecular recognition designs at the doped sites achieve NIR sensing of sugar molecules[9], metal ions[10], etc. Recent studies for PL solvatochromism of lf-SWCNTs reveal that excitonic properties of localized exactions at the doped sites are effectively modulated depending on chemical structure differences of doped sites in lf-SWCNTs.[11,12] Therefore, defect engineering based on the molecular functionalization for lf-SWCNTs is a powerful tool for NIR PL modulation, by which advanced optical applications such as high performance bio/medical imaging and sensing using NIR II windows and photonic nanodevices for quantum communication would be developed. [1] S. Iijima, T. Ichihashi, Nature 1993, 363, 603; [2] Y. Miyauchi, J. Mater. Chem. C 2013, 1, 6499; [3] T. Shiraki, Chem. Lett. 2021, 50, 397; [4] T. Shiraki et al., Acc. Chem. Res. 2020, 53, 1846; [5] Y. Wang et al., Nat. Rev. Chem. 2019, 3, 375; [6] D. Janas, Mater. Horiz. 2020, 7, 2860; [7] T. Shiraki et al., Sci. Rep. 2016, 6, 28393; [8] T. Shiraki, et al., Chem. Lett. 2019, 48, 791; [9] T. Shiraki et al., Chem. Commun. 2016, 52, 12972; [10] T. Shiraki et al., Chem. Eur. J. 2018, 24, 9393; [11] T. Shiraki et al., Chem. Commun. 2019, 55, 3662; [12] T. Shiraki et al., J. Phys. Chem. C 2021, 125, 12758.

Authors : Santanu Ghosh, Sreekanth Madakka, Debalaya Sarker and Pankaj Srivastava
Affiliations : Nanostech Laboratory Department of Physics Indian Institute of Technology Delhi New Delhi-110016 India

Resume : We present here field emission (FE) properties of two types of nanostructured composite films, promising novel materials for third generation electron sources and displays: (i) Nano-particle decorated multi-walled carbon nanotubes (MWCNTs)-and (ii) metal-insulator nano-composite thin-films. FE measurements were carried out in an indigenously developed high vacuum diode set up. The salient results obtained can be summarized as (i) a significant im-provement of FE current and temporal stability associated with an appreciable reduction in turn-on field from metal nanoparticle decorated MWCNT-films as compared to only MWCNT films: showing promises for electron-guns, x-ray sources etc.; (ii) appreciable increase in FE current density with high mechanical durability in metal nanoparticle decorated composites: promising planar emitter for future flat-displays. The enhanced FE characteristics of these emitters are understood from a combined experimental results, electronic structure and DFT based calculation.

Authors : Juan J. Vilatela
Affiliations : IMDEA Materials, Madrid, Spain

Resume : Fostering the enormous potential of nanomaterials requires assembling them as organized structures on a macroscopic scale. For 1D nanomaterials a natural embodiment is as aligned fibres or fabrics that efficiently exploit the axial properties of their constituents. This talk describes a method to produce macroscopic solids made of 1D nanostructured directly collected as they grow floating in the gas phase. The strategy consists in synthesising 1D nanostructures suspended in a gas stream using an aerosol of catalyst nanoparticles, i.e. via floating catalyst chemical vapour deposition (FCCVD). Under this synthesis mode, growth is ultrafast, around 1000 faster than in substrate-based processes. The resulting high aspect ratio (> 200) enables the aggregation of nanomaterials in the gas phase and ultimately the formation of network solids. The talk reviews the use of this synthetic route to produce different nanotubes (e.g. carbon nanotubes – CNTs) and nanowires (SiNW). It analyses the factors that control the different possible reaction path in FCCVD and introduces a basic kinetic model to rationalise aspects of the reaction inferred from analysis of the nanostructures. Finally, the talk shows that some of these macroscopic ensembles behave as “macromolecular” networks with many superior properties compared to monolithic materials: fibres of carbon nanotubes have tensile mechanical properties above many high-performance polymer fibres; fabrics of CNTs are ideal built-in porous current collectors to eliminate electron resistance limitations in composite battery electrodes, sheets of silicon nanowires are flexible and have high cyclability as lithium-ion battery anodes.

Authors : Darya Meisak 1,2, Jan Macutkevic 1, Polina Kuzhir 3,2 and Juras Banys 1
Affiliations : 1 Vilnius University, Sauletekio Ave. 3, LT-10222 Vilnius, Lithuania; 2 Institute for Nuclear Problems, Belarusian State University, Bobruiskaya st. 11, 220006 Minsk, Belarus; 3 Institute of Photonics, University of Eastern Finland, Yliopistokatu 7, FI-80101 Joensuu, Finland;

Resume : The dielectric/electric properties of the Ni@C (carbon-coated Ni)/epoxy composites and Ni@C/MWCNTs (multi-walled carbon nanotubes)/epoxy composites loaded with fixed MWCNTs amount just below the percolation threshold (0.09 vol.%) and Ni@C at different concentrations up to 1 vol.% were investigated in broad frequency (20 Hz–40 GHz) and temperature (30 K–500 K) regions. In composites with the only Ni@C nanoparticles the electrical percolation threshold was determined between 10 and 15 vol.%. Above the percolation threshold the dielectric permittivity (ε') and the electrical conductivity (σ) of the composites loaded with Ni@C only are high enough, i.e. ε'=105 and σ=0.6 S/m at 100 Hz for composites with 30 vol.% Ni@C, to be used for electromagnetic shielding applications. The annealing to 500 K was proved to be an effective and simple tool to decrease the percolation threshold in epoxy/Ni@C composites. For hybrid composites series an optimal concentration of Ni@C (0.2 vol.%) was determined, leading to the conductivity absolute values several orders of magnitude higher than that of a composite filled with MWCNTs only. The synergy effects of using both fillers have been discussed. Below the room temperature the electrical transport is mainly governed by epoxy resin compression in all composites, while the electron tunneling was observed only in hybrid composites below 200 K. At higher temperatures (above 400 K), in addition to the nanoparticles redistribution effects, the electrical conductivity of epoxy resin makes a significant contribution to the total composite conductivity. The dielectric relaxation spectroscopy allows estimating the nanoparticles distributions in polymer matrix and could be used as the non-destructive and fast alternate to microscopy techniques for general polymer composite fabrication control.

09:45 Q&A live session    
Authors : Madhurima Deb, Sumit Saxena, Rajdip Bandyopadhyaya, Shobha Shukla
Affiliations : Centre for Research in Nano Technology and Science, Indian Institute of Technology Bombay, Mumbai, MH 400076, India; Nanostructures Engineering and Modeling Laboratory, Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai, MH 400076, India; Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, MH 400076, India; Nanostructures Engineering and Modeling Laboratory, Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai, MH 400076, India

Resume : Reduced graphene oxide has become a reliable material for sensing applications due to possessing properties such as large surface area, high electrical conductivity and ability to interact with various chemical species. Heavy metals bind with proteins and pose a potential risk to human life when exposed to higher concentrations. Thus, precise and quick detection of heavy metals is essential. Here, we report the use of β-cyclodextrin (BCD) functionalized reduced graphene oxide (rGO) as a chemiresistive sensor material for heavy metals sensing in the aqueous medium. Functionalization of rGO led to selectivity towards lead (Pb(II)) detection. A significant change in resistivity was observed within 15 minutes when the BCD functionalized rGO film was exposed to Pb(NO3)2 solution of various concentrations. A chemiresistive device was fabricated and characterized. The development of simple and selective chemiresistive sensors is expected to provide a facile solution for heavy metal detection for point of use sensing devices.

Authors : Stefano Pecorario, Carlo S. Casari, Mario Caironi
Affiliations : Stefano Pecorario [1,2], e-mail:; Carlo S. Casari [2]; Mario Caironi [1] [1] Center for Nano Science and Technology@PoliMi, Istituto Italiano di Tecnologia, Milan 20133, Italy; [2] Department of Energy, Politecnico di Milano, 20133 Milano, Italy

Resume : Carbon Atomic Wires are attracting increasing interest as they are the one-dimensional allotropic form of carbon, featuring outstanding mechanical, optical and electronical properties. [1] Carbon Atomic Wires consist in linear chains of sp-hybridized carbon atoms and exhibit two possible isomeric configurations: cumulenes (sequence of double bonds) and polyynes (sequence of single and triple alternated bonds). To date, only a few experimental studies have investigated their electronic properties in solid-state devices and they have focused mainly on molecular junctions or monolayers. Herein, we demonstrate that cumulenic Carbon Atomic Wires own great potential as organic semiconductors for solution-processed thin-film electronics. We report on the first example of organic field-effect-transistor (FET) based on short cumulenes molecular crystals, namely tetraphenylbutatriene [3]Ph. [2] Furthermore, we discuss on our latest achievements in understanding and optimizing charge-transport properties in solution processed thin films of these molecules. In particular, we show how to control the deposition of large-area thin-films of [3]Ph via wire-bar coating, a scalable printing technique, and achieve field-effect-mobilities up to 0.1 cm2V-1s-1. An in-depth characterisation of films obtained with different processing parameters allow us to correlate microstructural and morphological features with the FETs electrical performance. Lastly, our [3]Ph-based transistors provide excellent operational stability in dark conditions, therefore addressing one of the major concerns for the application of Carbon Atomic Wires, and in general of organic semiconductors, in ambient conditions. These results pave the way to the use of cumulenes as active material for organic electronics and open new possibilities for the chemical design of performant organic semiconductors based on sp-hybridised molecules. [1] C. S. Casari, M. Tommasini, R. R. Tykwinski and A. Milani, Nanoscale 8 (8), 4414−4435, (2016). [2] A. D. Scaccabarozzi, A. Milani, S. Peggiani, S. Pecorario, B. Sun, R. R. Tykwinski, M. Caironi, and C. S. Casari, J. Phys. Chem. Lett. 11, 1970−1974, (2020).

10:25 Q&A live session    
Session 10- Energy Materials: Start-of-the-art Progress : R. Puglisi,, D. Janas, L. Polavarapu
Authors : M. Censabella1,2, F. Ruffino1,2, M. G. Grimaldi1,2,
Affiliations : 1Dipartimento di Fisica e Astronomia “Ettore Majorana”, Università di Catania, via S. Sofia 64, 95123 Catania, Italy 2CNR-IMM via S. Sofia 64, 95123 Catania, Italy

Resume : Nanomaterials have attracted widespread attention due to their tunable physical and chemical properties with enhanced performance over their bulk counterparts. The manipulation of matter at the nanoscale has opened enormous possibilities to meet challenges in different scientific and technological fields like optoelectronics, sensing, medicine, energy sustainability and engineering of new functional devices. Due to the exciting nature of nanostructures, nowadays, there is an increasing demand towards low-cost, effective and versatile nanofabrication methods. In particular, research efforts are focused on laser-based techniques for the growth and fabrication of nanostructures. In fact, laser-based techniques are simple and environmentally friendly and, in addition, with these methods is possible to control size, shape and composition of the materials being manufactured. In this talk, an overview of three different laser based techniques for the fabrication of different nanostructures, nanocomposites and thin films will be given.

Authors : Mark Portnoi, Paul Anthony Haigh, Thomas J. Macdonald, Filip Ambroz, Ivan P. Parkin, Izzat Darwazeh, Ioannis Papakonstantinou
Affiliations : University College London, Newcastle University, Imperial College, University College London, University College London, University College London, University College London

Resume : The Luminescent Solar Concentrator (LSC) was originally introduced over four decades ago, as a potential alternative to Si solar cells. Since then, the LSC concept has evolved quite significantly, finding an ever-expanding application space, [1]. This is owed to the LSC's highly desirable inherent ability to efficiently concentrate incident light, even if diffuse, making it an extremely versatile and powerful photonic technology platform. Conventionally, optical systems are limited by the principle of conservation of étendue, meaning that there is a trade-off between the acceptance angle and maximum concentration gain that can be achieved. However, in the presence of Stokes shift, etendue needs not to be conserved in the same way: both broad acceptance angles and high concentration gains that grow exponentially with Stokes shift can be achieved, while still adhering to the second law of thermodynamics. Taking advantage of the above property and the potential high optical gains, luminescent solar concentrators have recently emerged as a promising receiver technology in free-space optical communications. Several high-speed communication systems integrating LSCs in their detector blocks have already been demonstrated, with the majority of efforts so far being devoted to maximising the received optical power and the system?s field-of-view. However, LSCs may pose a severe bottleneck on the bandwidth of such communication channels due to the comparably slow timescale of the fluorescence events involved, a situation further aggravated by the inherent reabsorption in these systems, and yet, an in-depth study into such dynamic effects remains absent in the field. To fill this gap, we have developed a comprehensive analytical solution that delineates the fundamental bandwidth limits of LSCs as optical detectors in arbitrary free-space optical links, and establishes their equivalence with simple RC low-pass electrical circuits, [2]. Furthermore, we demonstrate a time-domain Monte Carlo simulation platform, an indispensable tool in the multiparameter optimisation of LSC-based receiver systems. Our work offers vital insight into LSC system dynamic behaviour and paves the way to evaluate the technology for a wide range of applications, including visible light communications, high-speed video recording, and real-time biological imaging, to name a few. [1]. Papakonstantinou, I., Portnoi, M., & Debije, M. G. ?The Hidden Potential of Luminescent Solar Concentrators?. Adv. Energy Mater., 11, 2002883, 2020. [2]. Portnoi, M., Haigh, P. A., Macdonald, T. J., Ambroz, F., Parkin, I. P., Darwazeh, I., & Papakonstantinou, I. (2021). ?Bandwidth Limits of Luminescent Solar Concentrators as Detectors in Free-Space Optical Communication Systems?. Light: Science & Applications, 10(3), 2021.

Authors : Anna Lucia Pellegrino, Graziella Malandrino
Affiliations : Dipartimento di Scienze Chimiche, Universita` di Catania and INSTM UdR Catania, V.le A. Doria 6, 95125 Catania, Italy

Resume : In recent years, there has been an exponential growth of research activities in the production of new and more efficient photovoltaic (PV) devices. One strategy to enhance the efficiency of PV devices is to collect the radiation energy outside the absorption range of the photoactive material (usually silicon) by shifting its energy to a more suitable optical region. This energy conversion could be actuated by up-conversion (UC) or down-conversion (DC) luminescent materials. The energy converter system consists of a host material doped with light-emitting active species. One of the most efficient material for energy conversion processes consist of alkaline earth fluoride matrices, such as CaF2 and NaLnF4 (Ln:Y,Gd), appropriately doped with Ln3+ ions, such as Eu3+, Yb3+- Er3+ and Yb3+- Tm3+. In addition, these systems are promising materials as phosphors in other technological applications as biomedical assays and for micro and nanoscale thermometry, due to the direct connection between temperature and luminescent behavior of emitting doping. However, most of these applications require the luminescent material in form of thin films. In the present study, we report the synthesis of Ln-doped fluoride thin films starting from fluorinated metalorganic β-diketonate compounds, through two different chemical approaches: Metal Organic Chemical Vapor Deposition (MOCVD) technique and a combined sol-gel/ spin-coating method. The former has the advantage of being a very reliable and reproducible method for the fast production of films with high uniformity degree over large areas; the latter has the potential advantage of being a tunable and a potential scaling up method for the production of different kind of films homogenous in thickness and composition. A systematic study of both synthetic routes has been carried out to optimize the Ln doped CaF2 and NaMF4 (M:Y,Gd) films through an accurate control of the process parameters. In addition, for the synthesis of β-NaYF4 nanostructured thin films, two different precursor sources have been tested: i) a mixture of β-diketonate ‘‘second generation’’ Na(hfa)•tetraglyme and Y(hfa)3•diglyme complexes; ii) the novel fluorinated “third-generation” bimetallic compound NaY(hfa)4tetraglyme, which acts as single precursor for the metal components and the fluorine. The doping ions are introduced in the materials using the RE(hfa)3•diglyme complexes (RE = Yb, Er, Eu). The synthesized films have been characterized though X-ray diffraction to determine their structure, field-emission scanning electron microscopy for their morphology and energy dispersive X-ray analyses to determine their composition. Finally, spectroscopic properties in the visible and near infrared regions upon laser excitation at 980 nm have been investigated.

Authors : Fatemeh Sadat Mirsafi1,2, Esmaeil Saievar Iranizad 1, Reza Abolhassani2, Till Leißner2, Serguei Chiriaev2 ,Horst-Günter Rubahn 2,Yogendra Kumar Mishra2*
Affiliations : 1Tarbiat Modares University, Tehran, Iran 2Mads Clausen Institute, NanoSYD, University of Southern Denmark, Alsion 2, 6400, Sønderborg, Denmark

Resume : Supercapacitors are considered as a well-established energy storage device which is currently used in digital communication equipment, electric vehicle, regenerative braking systems, and voltage stabilization. Although the market of supercapacitors is growing rapidly due to their considerable capabilities including high power density, excellent low-temperature performance, fast charge/discharge rates, relatively lower costs, longer operational life, and environmental friendliness, their low energy density compared to batteries leads to a major barrier for the future of this technology. Therefore, preparing novel materials with higher power densities is critical for potential supercapacitor electrodes. One of the most important factors to control a supercapacitor's performance is the structure and properties of the electrodes. Porous nanocomposite carbon-based materials have been viewed for electrode materials of electrochemical cells due to their high surface area, large pore volume, and unique pore size distribution. Nevertheless, they suffer from low specific capacitance and low energy density which make them a good candidate to composite with metal oxide. By combining the carbon-based materials and metal oxide, the achieved composite has demonstrated larger external surface areas, high electrical conductivity, high capacitance, high energy and power density, and excellent cycle stability In this research, mesoporous carbon-based materials will be prepared by hard-templating and soft-templating methods. The metal oxide will be obtained via the hydrothermal method. Finally, for the characterization of the obtained structures, electrochemical techniques will be used to investigate electrochemical and supercapacitive characteristics of the composites.

Authors : Luca M. Cavinato,a Elisa Fresta,a Claudio Garino,b Julio Fernández-Cestau,a Rubén D. Costa,a
Affiliations : a, Technical University of Munich, Chair of Biogenic Functional Materials, Schulgasse 22, 94315, Straubing, Germany. b, University of Turin, Department of Chemistry and NIS Interdepartmental Centre, Via Pietro Giuria 7, 10125, Torino, Italy.

Resume : Copper(I) complexes are one of the most promising ionic transition metal complexes (iTMCs) towards low-cost and sustainable lighting devices due to their optimal photophysical features and Cu abundance. Since 1970s[1] the photophysical behavior of copper (I) complexes with two chelating diimine ligands (N^N) have widely been investigated. In general, the emissive properties of the heteroleptic family [Cu(P^P)(N^N)][PF6] are far much better than those of the respective homoleptic family [Cu(N^N)2][PF6]. In addition, they often show thermal repopulation of the emitting singlet excited state from the lowest-lying triplet excited state, i.e., thermally activated delayed fluorescence (TADF) emission mechanism, allowing 100% electron harvesting. Up to date, single-layer Cu-iTMCs-based light-emitting electrochemical cells (LECs) can be driven at very low voltage reaching bright emission covering the visible spectrum; though white devices are still missing.[2,3] Herein, we have synthetized and characterized two novel blue-emitting heteroleptic [Cu(P^P)(N^N)][PF6] (λem=490 nm with ϕ= 40%). The corresponding LECs devices featured blue electroluminescence, achieving the best efficacy (3.6 cd A-1) reported up to date. In addition, they were blended with a previously published red-emitting Cu-iTMC,[4] realizing white-emitting devices with luminances of 30 cd m-2 and efficiencies of 0.6 cd A-1. The electroluminescence spectra corresponded to a white light output with x/y Commission Internationale de l’Éclairage 1931 (CIE) color coordinates of 0.29/0.35 associated to a color correlated temperature (CCT) of ca. 7400 K. So far, we reported the most stable and efficient fully copper(I)-based white-emitting LEC. Contextually, the two complexes have been investigated in detail through a joint theoretical and experimental investigation. Overall, this work pinpoints how critical the complex architecture is towards the design of highly efficient TADF LECs based on copper(I) complexes and the reported results constitute an important milestone toward sustainable and highly performing white-emitting LECs. References [1] D. R. McMillin et al., Inorg. Chem, 16, 943. (1977) [2] M.D. Weber et al., Dalton Trans., 45, 8984. (2016) [3] E. Fresta et al., J. Mater. Chem. C, 5, 5643-5675 (2017) [4] E. Fresta et al., Adv. Opt. Mater., 7, 1-11 (2019)

13:10 Q&A live session / Lunch Break    
Session 11-Hybrid Nanomaterials: Growth & Applications : D. Janas, J. Adam, R. Puglisi, L. Polavarapu, Y. K. Mishra
Authors : Emerson Coy
Affiliations : NanoBioMedical Centre, Adam Mickiewicz University, Wszechnicy Piastowskiej 3, 61-614, Poznan, Poland

Resume : Recently, biomimetic polymers, specifically Polydopamine (PDA), have shown enhanced photocatalytic performance when combined with photoactive materials such as ZnO, TiO2, ZnS, among others. This talk presents recent developments and challenges of PDA/Semiconductor materials, covering the advances in PDA films from the air/water interface, nanocomposites and leading applications in energy production and water remediation[1-3]. Acknowledgements: National Science Centre (NCN) of Poland by the OPUS grant 2019/35/B/ST5/00248 Refernences: [1] Y. Kim, et al, Appl. Catal. B Environ. 2021, 280, 119423. [2] E. Coy, et al, ACS Appl. Mater. Interfaces 2021, acsami.1c02483. [3] D. Aguilar-Ferrer, J et al, Catal. Today 2021.

Authors : Sungjun Kim, Jin-Hong Park, Keun Heo
Affiliations : Sungjun Kim; Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, South Korea; Jin-Hong Park; Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, South Korea; Keun Heo; School of Semiconductor and Chemical Engineering, Semiconductor Physics Research Center, Jeonbuk National University, Jeoju 54896, South Korea

Resume : With the coming of the 4th Industrial Revolution, represented by Artificial intelligence (AI), Internet of Things (IoT), and Big-data processing, the demand of the new computing scheme for numerous data processing with less energy consumption in a short period of time has been rapidly increased. The conventional von Neumann computing architecture which is separating logic and memory blocks faced the challenge of the extensive power consumption and time delay by serial computing to transfer data between each block. A neuromorphic computing that mimics human brain functionalities has been considered that can overcome the limitation of von Neumann-based computing systems with its characteristics of parallel computing capability with energy-efficient data processing. From an energy efficiency point of view at the neuromorphic system, many candidates for synaptic devices have been suggested such as phase-change memory, resistive change memory, conductive bridge memory, and ferroelectric memory. However, it is still challenging to implement low power neuromorphic system with these emerging memories since more switching power reduction should be realized for parallel array application. Among the aforementioned applications, the ferroelectric device is one of the promising candidates for synaptic devices due to its low power and fast switching characteristics. In this work, we investigated the ferroelectric synaptic device based on metal-ferro-metal (MFM) structure using polyvinylidenefluoride-trifluoroethylene (P(VDF-TrFE)) copolymer. We fabricated MFM capacitors with respect to various PVDF weight percents, PVDF / TrFE composition ratio, and thickness of the ferroelectric polymer. Each sample’s ferroelectric characteristics e.g. coercive field, remnant polarization, and hysteresis were evaluated. Additionally, the synaptic plasticity characteristics such as long-term potentiation and long-term depression (LTP/LTD), and spike-timing-dependent plasticity (STDP) were thoroughly examined with each MFM capacitor. With these efforts, we could analyze the relation between ferroelectric switching properties and synaptic plasticity characteristics.

Authors : Daniel A. Heller, Mijin Kim, Chen Chen, Peng Wang, Rachel E. Langenbacher, Rune Fredericksen, YuHuang Wang
Affiliations : Memorial Sloan Kettering Cancer Center, New York, NY USA; University of Maryland, College Park, MD USA

Resume : The modulation of single-walled carbon nanotube (SWCNT) photoluminescence has been under investigation for the unique potential to develop biosensors to detect many classes of analytes. Covalent sp3 defects on SWCNTs, sometimes dubbed organic color centers (OCCs) or carbon color centers (CCCs) have been explored for their photoluminescent properties, including the potential for introducing new emission bands, increasing quantum yield, and introducing new chemical sensitivities. The application of OCCs for biomedical applications requires new methods to both conduct covalent chemistry and to concomitantly control the surface chemistry and the resulting biological interactions/biocompatibility via their supramolecular interactions with polymers and other excipients. We have found specific utilities of OCCs for the detection of chemical phenomena where SWCNT photoluminescence is normally relatively insensitive, such pH changes in the physiologic range of 4.5 - 8. We have developed OCCs to measure endolysosomal pH in live cells and in vivo, as well as other emerging applications. We believe that OCCs will facilitate the development of biosensors for disease detection and biomedical research.

15:15 Q&A live session    
Authors : Anastasiya Sergievskaya(1), Amy O’Reilly (1), Adrien Chauvin (1, 2), Kamakshi Patel (1), Julien De Winter (3), Jozef Veselý (4), Halima Alem (5), Adriano Panepinto (6), David Cornil (7), Jérôme Cornil (7), Stephanos Konstantinidis (1)
Affiliations : (1) Plasma-Surface Interaction Chemistry (ChIPS), University of Mons, Avenue Copernic 3, 7000 Mons, Belgium; (2) Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Praha 2, Czech Republic; (3) Organic Synthesis and Mass Spectrometry Laboratory (S²MOs), University of Mons, 23 Place du Parc, B-7000 Mons, Belgium; (4) Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Praha 2, Czech Republic; (5) Université de Lorraine, CNRS, IJL, F-54000 Nancy, France; (6) Materia Nova Research Center, 3 Avenue Nicolas Copernic, Parc Initialis, 7000 Mons, Belgium; (7) Laboratory for Chemistry of Novel Materials (CMN), University of Mons, Place du Parc 23, Mons 7000, Belgium

Resume : Low-pressure (1 Pa) plasma-based Magnetron Sputter (MS) deposition of metal targets onto liquids allows obtaining dispersions of small spherical nanoparticles (NPs). The main advantages of the method are its reproducibility and high purity of the final NPs. Indeed, only two components – target material and liquid molecules – are present in the solution, and no additional reducing or stabilizing reagents are required. Despite magnetron sputtering onto liquids has been studied since 1996, the mechanism of NP formation is still not fully understood. To provide more insight on this topic, sputtering of gold, silver, and copper targets onto vacuum-sustaing castor oil, rapeseed oil, and its polymers has been systematically studied. The effects of sputtering time, sputter power, argon gas pressure, type of sputtering plasma (Direct Current Magnetron Sputtering (DC-MS) vs High-Power Impulse Magnetron Sputtering (HiPIMS)), and viscosity of host liquid onto NP properties have been studied experimentally and by quantum-chemistry calculations. Moreover, in situ temperature measurements have allowed us to better understand how the heating of the liquid during the plasma treatment affects the formation of NPs. Magnetron sputtering of gold, silver, and copper targets leads to the formation of a dense cloud of particles underneath the oil surface which can be easily homogenized by mechanical stirring but films are formed in the case of high-viscosity oils. Gold NPs have higher stability in castor oil solutions than silver NPs, but secondary growth processes take place. Copper NPs rapidly oxidize due to reaction with oil molecules, inducing the formation of intermediate compound between copper and oil components and, finaly, the growth of copper oxide NPs. According to TEM the diameters of primary NPs obtained with the DC-MS plasma are in the range of 2.4 – 3.2 nm for gold, 0.8 – 4.0 nm for silver, and 2 – 4 nm for copper oxide. Depositions in HiPIMS mode allow the formation of NPs almost twice bigger in case of gold and silver. Moreover, applying a bipolar HiPIMS power supply leads to the formation of larger aggregated NPs which is discussed in terms of liquid heating and kinetic energies of the sputtered species.

Authors : Francesca Mirabella, Marek Mezera, Karsten Wasmuth, A. Richter, K. Schwibbert, Jörg Krüger, Jörn Bonse, and Vasile-Dan Hodoroaba
Affiliations : Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany

Resume : In recent years, the fabrication of laser-generated surface structures on metals such as titanium surfaces have gained remarkable interests, being technologically relevant for applications in optics, medicine, fluid transport, tribology, and wetting of surfaces. The morphology of these structures, and so their chemistry, is influenced by the different laser processing parameters such as the laser fluence, wavelength, pulse repetition rate, laser light polarization type and direction, angle of incidence, and the effective number of laser pulses per beam spot area. However, the characterization of the different surface structures can be difficult because of constraints regarding the analytical information from both depth and the topographic artifacts which may limit the lateral and depth resolution of elemental distributions as well as their proper quantification. A promising technique to investigate these structures even at the nano-scale is Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), a very surface sensitive technique that at the same time allows to perform depth-profiling, imaging and 3D-reconstruction of selected ion-sputter fragment distributions on the surface. In this study we combine chemical analyses such as Energy Dispersive X-ray spectroscopy (EDX) and high-resolution scanning electron microscopy (SEM) analyses with ToF-SIMS to fully characterize the evolution of various types of laser-generated micro- and nanostructures formed on Ti and Ti alloys at different laser fluence levels, effective number of pulses and at different pulse repetition rates (1 – 400 kHz), following irradiation by near-infrared ultrashort laser pulses (925 fs, 1030 nm) in air environment or under argon gas flow. We show how this combined surface analytical approach allows to evaluate alteration in the surface chemistry of the laser-generated surface structures depending on the laser processing parameters and the ambient environment.

Authors : Pizzone, M.*(1)(2), A. La Magna (1), Grimaldi, M.G. (2), Rahmani, N. (3), Scalese, S. (1), Adam, J. (3) & Puglisi, R.A. (1).
Affiliations : (1) Istituto per la Microelettronica e Microsistemi, Consiglio Nazionale delle Ricerche, Strada Ottava 5, Zona Industriale, 95121 Catania, Italy; (2) Dipartimento di Fisica e Astronomia “Ettore Majorana”, Università degli Studi di Catania, Via S. Sofia, 64, 95123 Catania, Italy; (3) Computational Materials Group, Department of Mechanical and Electrical Engineering (DME), University of Southern Denmark (SDU), Sønderborg, Denmark * lead presenter

Resume : Molecular Doping (MD) is a technique in which dopant-containing molecules, used as a dopant source, are deposited on top of a semiconductor and diffused inside it through a drive-in process. Every phase of the MD process represents a step onto which subsequent phases will build upon to obtain the final doped sample, so an in-depth study of each phase will improve the control on the electrical properties of the final doped samples. Hence, studying the chemical bonds forming during the deposition step between the molecules becomes an essential aspect to be studied. It is already known from the literature1 that the molecules form a self-assembled monolayer over the semiconductor, but little is known on the possible multiple layers forming on top after prolonged deposition times. To this end, we performed high-resolution morphological analyses to investigate the molecular surface coverage at different timestamps and examined the effect of the surface treatments on it. To gain deeper theoretical insight on the bonding nature, we pair these analyses with density functional theory simulations, as an extension of the previous study2, and with electrical measurements of the final doped samples. We find information on the type of chemical bonds forming between the several layers of molecules and how they impact the doping profile. This will allow for a more precise tuning of the electrical properties of MD-based devices. 1 S. Caccamo et al., Materials Science in Semiconductor Processing 42, 200-20 (2016) 2 Puglisi, R.A., et al. Direct observation of single organic molecules grafted on the surface of a silicon nanowire. Sci Rep 9, 5647 (2019).

Authors : Christina Koutsiaki, Demosthenes Koutsogeorgis and Nikolaos Kalfagiannis
Affiliations : Nottingham Trent University, School of Science and Technology, Clifton Campus, Nottingham, NG11 8NS; Nottingham Trent University, School of Science and Technology, Clifton Campus, Nottingham, NG11 8NS ; Nottingham Trent University, School of Science and Technology, Clifton Campus, Nottingham, NG11 8NS

Resume : Over the last decade, the transition from conventional vacuum based thin film deposition techniques to solution processes has remarkably empowered the evolution of a novel manufacturing scheme. Besides time and cost-efficiency included in their major advantages, solution processes additionally present an outstanding compatibility with a plethora of materials. Amongst them, metal oxides (MOs) constitute an attractive research field, as their significantly enhanced optoelectronic properties, concomitantly with high optical transparency and mechanical stability render them as highly promising. ?Sol-gel? is established as one of the currently favourable solution processes, as it uniquely links metal oxides to solution processing. This deposition of organometallic precursors via wet techniques, followed by a subsequent thermal treatment, prevails the formation of high-quality metal oxides, while accommodating essential advantages such as ambient processing conditions and composition tuning. However, these advantages may simultaneously constitute challenging manufacturing points. This, coupled with a high demand on ultra-thin films (< 10 nm) in IC industry, constitutes the presence of high-sensitivity characterization techniques as essential in sol-gel industry. So far, well-established methods such as XPS and TEM have been widely used in sol gel research. However, their cost and time-consuming nature hinders their implementation in a high-throughput production line. In addition, their ?destructive? character restricts the possibility of in situ monitoring during fabrication. Therefore, the presence of non-invasive, highly-sensitive characterization techniques could introduce a remarkable upgrade of sol gel research and industry. To address this challenge, we propose Infra-Red Spectroscopic Ellipsometry as an alternative and novel approach towards the clarification of the sol gel precursor conversion stages, the control of which leads to high quality metal oxide ultra-thin films. Particular focus is being paid in the role of substrates, as their tuning may enhance the detection of spectral features, thus allowing the detection of vibrational modes in ultra-thin films (~ 1 nm). In this study, In(NO3)3 dissolved in 2-Methoxyethanol (C3H8O2) is conversed into an ultra-thin In2O3 film (< 10 nm), a widely popular metal oxide semiconductor. The individual stages are captured by IRSE, aiming to shed light into the sol gel reaction conversion. For this, various substrates are being utilized (Al, TiN, Au and Si), aiming to enhance the IRSE sensitivity, thus provide a clear monitoring of the conversion process through vibrational mode detection. We thus identify the intermediate products during transition towards In2O3. This introduces IRSE as a new route towards the detection of sol-gel stages in ultra-thin films, with its implementation in solution processing technologies being potentially essential. The substrate effect is further reinforcing the importance of IRSE in thin film industry, as it potentially covers an expanded material palette, such as 2-D materials.

16:30 Q&A live session    
Authors : Francesca Lo Presti, Anna Lucia Pellegrino, Graziella Malandrino
Affiliations : Dipartimento di Scienze Chimiche, Universita` di Catania and INSTM UdR Catania, V.le A. Doria 6, 95125 Catania, Italy.

Resume : In recent years, lanthanide metal-organic frameworks (Ln-MOF) have displayed interesting properties making them appealing for various applications. The use of lanthanide elements as dopants within MOF’s structures leads to the acquirement of unique luminescent properties, which can be exploited for the fabrication of optical sensors. Up to now, different Ln-MOFs have been studied for the detection of toxic ions, heavy metals, and small molecules. The special feature of these materials refers to the capability of tailoring their properties by simply changing their internal structure, through variation of the organic linkers and the metallic centre or by modifying the operating conditions such as time, temperature and pressure. So far, the scientific community has focused great attention on the development of new and environmentally friendly strategies for the synthesis of Ln-MOF to obtain more and more complex structures with the best properties, but having at the same time a low environmental impact. The most recent applied strategy for the syntheses of Ln-MOFs is the solvothermal reaction which uses organic solvents, high pressure and very long reaction times. The challenge in the development of more sustainable synthetic strategies actually leads to the exploration of new and greener approaches. In this context, we propose a one-step synthesis under mild conditions of Eu doped Ln-MOF (Ln = Gd, Y, Tb) in water/ethanol solvents. The use of 1,3,5-benzenetricarboxylic acid (H3BTC) as the organic ligand and Ln(NO3)∙nH2O as a source of Y, Tb and Eu results in the formation of Y,Eu-BTC and Tb,Eu-BTC. The Gd-MOF and Eu-doped Gd-MOF is formed by using the ditopic 1,4-benzenedicarboxylic acid (H2-BDC) linker, yielding respectively Gd-BDC and Gd,Eu-BDC networks. The obtained powders were characterised by X-ray diffraction (XRD), FT-IR spectroscopy and field emission scanning electron microscopy (FE-SEM) for the investigation of structure and morphology. Finally, preliminary studies were performed in order to investigate the luminescent properties of Ln-MOF doped with Eu ions, specifically Gd-BDC and Gd,Eu-BDC MOFs have been applied to the sensing of Fe3+ and Cr2O72-.

Authors : A. Sciortino, F. Ferrante, G. Gonçalves, G. Tobias, R. Popescu, D. Gerthsen, N. Mauro, G. Giammona, F. M. Gelardi, S. Agnello, M. Cannas, D. Duca, F. Messina
Affiliations : Università degli studi di Palermo, Dipartimento di Fisica e Chimica - Emilio Segrè, Via delle Scienze, Edificio 17, Palermo, 90128, Italy; Università degli studi di Palermo, Dipartimento di Fisica e Chimica - Emilio Segrè, Via delle Scienze, Edificio 17, Palermo, 90128, Italy; TEMA, Mechanical Engineering Department, University of Aveiro, 3810-193, Aveiro, Portugal; Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193, Bellaterra (Barcelona), Spain; Laboratory for electron Microscopy, Karlsruhe Institute of Technology, Engesserstrasse 7, 76131, Karlsruhe, Germany; Laboratory for electron Microscopy, Karlsruhe Institute of Technology, Engesserstrasse 7, 76131, Karlsruhe, Germany; Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche (STEBICEF), Università degli studi di Palermo, Via Archirafi 32, 90123, Palermo, Italy; Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche (STEBICEF), Università degli studi di Palermo, Via Archirafi 32, 90123, Palermo, Italy; Università degli studi di Palermo, Dipartimento di Fisica e Chimica - Emilio Segrè, Via delle Scienze, Edificio 17, Palermo, 90128, Italy; Università degli studi di Palermo, Dipartimento di Fisica e Chimica - Emilio Segrè, Via delle Scienze, Edificio 17, Palermo, 90128, Italy; Università degli studi di Palermo, Dipartimento di Fisica e Chimica - Emilio Segrè, Via delle Scienze, Edificio 17, Palermo, 90128, Italy; Università degli studi di Palermo, Dipartimento di Fisica e Chimica - Emilio Segrè, Via delle Scienze, Edificio 17, Palermo, 90128, Italy; Università degli studi di Palermo, Dipartimento di Fisica e Chimica - Emilio Segrè, Via delle Scienze, Edificio 17, Palermo, 90128, Italy;

Resume : Carbon Nanodots (CDs) are carbon nanoparticles characterized by intense and tunable absorption-emission in the visible range 1. Their optical response is combined with a great sensitivity to external agents2. Besides, CDs display exceptional electron donating capabilities, interesting for several applications2, 3. The combination of all of these characteristics promisingly projects the use of CDs as suitable substitutes of quantum dots in many optoelectronic or photo/electro-catalysis applications. Single-wall Carbon Nanotubes (SWCNTs) are probably one of the most iconic materials in nanoscience, endowed with a range of exceptional properties ultimately related to their 1D structure 4. By decorating the surface of CNTs with various functional groups or molecules5, it is possible to increase their colloidal stability, and to prepare them for coupling to other nanomaterials, such as CDs. Here, we synthesized nanocomposites of CDs + CNTs, and studied their interactions by the synergy of different structural and optical techniques, supported by DFT investigations. Their successful coupling is directly shown by HRTEM measurements and demonstrated by optical methods: the photoluminescence of CDs is quenched when they form complexes with nanotubes, indicating a strong electronic coupling. This interpretation is confirmed by ultrafast transient absorption spectroscopy, which directly highlights a very fast electron transfer (<60 fs) followed by a slower back electron transfer ( 60 ps) from the nanotube to the carbon dots. The reported results pave the way to use these "all-carbon" nanocomposites as efficient light harvesters for applications in artificial photocatalysis and photosynthesis. 1. Sciortino, A. et al. C-Journal of Carbon Research 2018, 4 (4), 35. 2. Zu, F. al. Microchimica Acta 2017, 184 (7), 1899-1914. 3. Arcudi, F. et al. Angewandte Chemie-International Edition 2017, 56 (40), 12097-12101. 4. Rahman, G. et al. C-Journal of Carbon Research 2019, 5 (1), 31. 5. Tasis, D. et al. Chemical Reviews 2006, 106 (3), 1105-1136.

Authors : Ankit Chauhan1 , Ashish Prajapati1 and Gil Shalev1,2*
Affiliations : 1 School of Electrical & Computer Engineering, Ben-Gurion University of the Negev, POB 653, Beer-Sheva 8410501, Israel 2 The Ilse-Katz Institute for Nanoscale Science & Technology, Ben-Gurion University of the Negev, POB 653, Beer-Sheva 8410501, Israel. *E-mail:

Resume : Absorption of the solar radiation over a wide spectral range is of an utmost importance to applications related to the harvesting of the solar energy. We numerically as well as experimentally demonstrate broadband solar absorption enhancement employing a metamaterial in the form of arrays composed of subwavelength silicon truncated inverted cones, henceforth referred to as light funnel (LF) arrays. Light trapping in arrays composed of subwavelength light funnel arrays (LF arrays) is a promising approach towards efficient broadband absorption of the solar radiation. In the following we examine the origin of light trapping enhancement in LF arrays as compared to nanopillar (NP) arrays and we show that light trapping enhancement is due to favorable strong optical coupling between adjacent light funnels which is not realized in NP. We suggest that the enhanced light trapping and absorption in dense LF arrays is governed by strong modal excitation coupled with high filling ratio, unlike the absorption in dense optimized nanopillar arrays which is governed by weak modal excitation and high filling ratio. In this current study optical near-field of LF and NP arrays has been explored experimentally using near-field optical microscopy. We show that in LF arrays the near-field increases as the array period decreases in contrast with NP arrays in which the near-field decreases with decreasing array period. Therefore, it is suggested that the origin to the broadband absorption in compact LF arrays is due to field overlap of adjacent LFs which increases the absorption cross-section of the individual LFs composing the array. This enhancement in the absorption cross section and the higher filling ratio in compact arrays produce broadband absorption that is significantly higher than that of optically-optimized NP arrays.

Authors : Harsh Gupta*1, Santanu Ghosh1, Ravi K Bommali2, Pankaj Srivastava1
Affiliations : 1Nanostech Lab., Indian Institute of Technology Delhi, India 2St.Xavier’s College Ranchi, India

Resume : Silicon nitride thin films are promised as a good candidate for anti-reflection coatings and third-generation quantum dot-based solar cells1,2. Variation in the stoichiometry (x = [N]/[Si]) of a-SiNx:H can regulate different optical properties of the material, making it suitable for different optoelectronic devices. SHI irradiation, annealing and other treatments can alter various properties of a-SiNx:H by changing the hydrogen content and density of thin films. SHI irradiation is widely accepted as a desirable technique for modification and change in properties of thin films and nanostructures embedded in different matrices. Singh et al. reported in-situ agglomeration of excess Si into Si nanostructures in host silicon nitride matrix. For swift heavy ion irradiationat lower fluences, a dissolution of Si nanostructures was observed, whereas the further increase in fluence resulted in the formation of amorphous Si nanostructures3.The origin of latent ion tracks microstructure evolution and changesin amorphous SiNx upon SHI irradiation at various fluences was also observed4,5. These results show different structural evolution in SiNx thin films upon irradiation. The different evolution can be understood in terms of stoichiometry and its effect on ion material interaction.The present work reports the effect of SHI irradiation on sub-stoichiometric a-SiNx:H thin film on their properties. Thin films of different stoichiometry (x = 1.42 to Si-rich x = 0.17) were irradiated with various fluences of 100 MeV Au8+ ions. The various properties of as-deposited and SHI irradiated a-SiNx:H films are explored in detail.The out-diffusion of Hydrogen due to irradiation is quantified with the help of ERDA.RBS was probed to study the change in thin films’ composition upon irradiation, which further helps understand the change in thin films’ optical properties. Quenching of photoluminescence in the films with all stoichiometries was also observed due to ion irradiation. X-TEM images show the formation of discontinuous ion tracks of radius 2.5 nm in the film closer to silicon nitride stoichiometry. However, Si rich film does not show the clear formation of tracks. Results are explained in the framework of the Thermal spike mechanism of ion-solid interaction. The observation ofthe discontinuous ion track-like structures upon swift heavy ion irradiation is explained on the basisof a dynamic electronic energy loss in the course of irradiation resulting fromthe out-diffusion of Hydrogen from the thin films and a continuous increase in density ofa-SiNx:H. References: 1 J. Schmidt and M. Kerr, Sol. Energy Mater. Sol. Cells 65, 585 (2001). 2 H.K. Raut, V.A. Ganesh, A.S. Nair, and S. Ramakrishna, Energy Environ. Sci. 4, 3779 (2011). 3 S.P. Singh, S. Ghosh, G. Vijaya Prakash, S.A. Khan, D. Kanjilal, A.K. Srivastava, H. Srivastava, and P. Srivastava, Nucl. Instruments Methods Phys. Res. Sect. B Beam Interact. with Mater. Atoms 276, 51 (2012). 4 L.A. Vlasukova, F.F. Komarov, V.N. Yuvchenko, V.A. Skuratov, A.Y. Didyk, and D. V. Plyakinc, in Bull. Russ. Acad. Sci. Phys. (2010), pp. 206–208. 5 R.K. Bommali, S. Ghosh, G. Vijaya Prakash, D. Kanjilal, P. Mondal, A.K. Srivastava, P. Srivastava, R.K. Bommali, D. Kanjilal, S. Ghosh, A.K. Srivastava, P. Mondal, and G.V. Prakash, Mater. Res. Express 2, 46204 (2015).

17:45 Q&A live session, Concluding Remarks, Feedbacks, Outlooks    

Symposium organizers
Dawid JANASSilesian University of Technology, Gliwice, Poland

Krzywoustego 4, 44-100 Gliwice, Poland
Jost ADAM (Main Organizer)University of Kassel

Computational Materials and Photonics (CMP), FB 16 - Wilhelmshöher Allee 71, D-34121 Kassel, Germany
Lakshminarayana POLAVARAPUCINBIO, Universidade de Vigo

Materials Chemistry and Physics Group, Department of Physical Chemistry, Campus Universitario Lagoas, Marcosende, 36310 Vigo, Spain

Strada Ottava 5 Z.I., 95121 Catania, Italy
Yogendra Kumar MISHRA (Main organizer)Mads Clausen Institute, University of Southern Denmark

Alsion 2, 6400, Sønderborg, Denmark