2017 Fall Meeting
BIO- AND NANO MATERIALSS
Materials- nanoelectronics & -nanophotonics
This symposium will cover:
- Materials growth: From 0D - 3D nanomaterials.
- Investigations: Structure-property Relations, Computation Modeling, Analytical Simulations.
- Applications: (a) Nanoelectronics- Gas/Pressure/Chemical/Biological Sensors, (b) Plasmonics/ Nanophotonics/Solar Cells/Photovoltaics, (c) Piezoelectrical/Energy Harvesting (e) Photocatalysis (f) Antiviral/Antibacterial/Biomedical.
Micro- and nanoscale structures particularly from inorganic metal oxide materials and carbon family are very important material candidates because of their size and shape dependent interesting physical and chemical properties suitable for various technological applications. The on going deployments in the direction of 2D and 3D networked materials have become further very relevant in terms of application aspects because, on one hand, they exhibit the necessary nanoscale features, and on the other hand, they exhibit less utilization complexities. Due to their sufficiently large size, they can be easily handled or integrated in desired manner in the devices or sensors. Thanks to interesting plasmonic properties, 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 technological applications. When these metal oxides are combined with metals in form of hybrid nanomaterials, they become further very relevant in terms of understanding the properties and accordingly applications. The family of carbon nanostructures, i.e., fullerenes, carbon nanotubes, graphene, graphene oxide, etc., has shown very strong potential ranging from fundamental properties to advanced energy applications and hence has been the subject of great attention in the past decades and the recent developments in the direction 3D carbon networks have opened an entirely new dimensions in nanotechnology research. Research on 3D flexible ceramics from metal oxides interconnected networks, which is currently going on now-a-days, is very important because it can be very helpful in up scaling the nanotechnology related applications.
However, the appropriate growth of different structures (0D, 1D, 2D and 3D) using simple methods, understanding their structure properties relations, their applications in different directions, etc. are still very interesting aspects and it requires an interdisciplinary research platforms which are equipped with: (i) fabrication groups for developing different nanostructures, (ii) computational scientists who can do simulations to understand the structure-property relations, and (iii) application groups who can accordingly utilize the nanostructures in different applications and this is actually the main aim of the present symposium.
Hot topics to be covered by the symposium:
- Inorganic Metals and Metal Oxide Materials (0D to 3D): Fabrication & Characterizations, Structure-property relations, Simulations studies, Applications: Nanoelectronics- Sensing- Biomedical- Energy Harvesting- Photocatalysis- Environmental- Membranes- Antiviral- Biomedical- Applications.
- Plasmonic Nanostructures: Synthesis & Characterizations, Computational Modeling, Sensing- Nanophotonics- Waveguide- Lasing- Nanoelectronics- Applications.
- Carbon Family (Fullerenes to 3D graphene): Fabrication & Characterizations, Structure-property relations, Simulations studies, Applications: Nanoelectronics- Sensing- Supercapacitor-Bioelectronics- Batteries-Energy.
- Hybrids and Composites: Inorganic-carbon-rubber-polymer based composites, Applications-Sensing- Self reporting- Self healing.
- Synchrotron radiations/Ion beams based materials characterizations and engineering.
Tentative list of invited speakers:
- Hidenori Mimura, Shizuoka University, Japan
- Jan Linnros, KTH, Sweden
- Sanjay Mathur, Cologne, Germany
- Susanne Hoffmann-Eifert, FZ-Jülich, Germany
- Devesh Avasthi, Amity Univ, India
- Mady Elbahri, Aalto Univ, Finland
- Svetlana Neretina, University of Notre Dame, USA
- Aadesh Singh, Chalmers University, Sweden
- Ramesh Chandra, IIT Roorkee, India
- Nimai Mishra, Italian Institute of Technology, Italy
- Amit Bhatnagar, University of Estern Finland
- Mustafa M. Demir, Izmir Institute of Technology, Turkey
- Tomas Tamulevicius, Kaunas University of Technology, Lithuania
- Asgar Mortensen, University of South Denmark, Denmark
- Miguel Manso Silvan, Universidad Autónoma de Madrid, Spain
- Andreas Seifert, NanoGUNE, Spain
- Tomasz Kawalec, Jagellonian University, Poland
- Li Xuanhua, Northwestern Polytechnical University, China
- Hidenori Mimura, Shizuoka University, Japan
- Lakshminarayana Polavarapu, Ludwig Maximilian University of Munich, Germany
Tentative list of scientific committee members:
- Rainer Adelung, Germany
- Franz Faupel, Kiel, Germany
- Devesh Kumar Avasthi, India
- Rajeev Ahuja, Sweden
- Hisatoshi Kobayashi, Japan
- Ashutosh Tiwari, Sweden
- Amit Bhatnagar, University of Eastern Finland, Finland
- Lorenz Kienle, Germany
- Tae Young Kim, South Korea
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Plasmonics_1 : Jost Adam, Oliver Schmidt
Authors : Svetlana Neretina, Robert A. Hughes, Eredzhep Menumerov, Spencer Golze
Affiliations : University of Notre Dame, Notre Dame, Indiana 46556, USA
Resume : One of the foremost challenges in nanofabrication is the establishment of a processing science that integrates wafer-based materials, techniques, and devices with the extraordinary physicochemical properties accessible when materials are reduced to nanoscale dimensions. Within this realm, plasmonic nanostructures offer the unique opportunity for realizing collective behaviors, nanostructure coupling phenomena, and interactions with adjacent bulk-scale materials due to interactions with plasmonic near-fields and hot electrons. Forming periodic arrays of complex plasmonic nanostructures has, however, proved challenging. Here, we describe a hybrid synthetic strategy that integrates vapor-phase directed assembly techniques with template-mediated colloidal growth modes to obtain organized surfaces of complex noble metal nanostructures. The devised strategy takes advantage of the relative ease by which periodic arrays of near-hemispherical single-component metal nanostructures are fabricated using templated dewetting. It then transforms these structures into far more sophisticated structures by carrying out wet-chemistry at the liquid-substrate interface. Demonstrated are (i) additive processes where material is deposited onto the template, (ii) subtractive processes where the template is partially consumed, and (iii) multistage processes that combine the additive and subtractive strategies in a sequential manner. The so-formed surfaces, because of their chemically and optically activity, have the potential to underpin photovoltaic, catalytic, and sensing applications. 1. S. Neretina, R. A. Hughes, K. D. Gilroy, M. Hajfathalian, Noble metal nanostructure synthesis at the liquid-substrate interface: New structures, new insights and new possibilities, Acc. Chem. Res. 2016, 49, 2243-2250. (Invited review article).
Authors : Maria Carmen Morant-Miñana, Eneko Lopez, Andreas Seifert
Affiliations : CIC nanoGUNE, Tolosa Hiribidea, 76 E-20018 Donostia San Sebastian, Spain
Resume : The detection of diseases at their early stages represents a key factor on current medical diagnosis. In most cases, a lack of specific detection methods and the non-specificity of symptoms mask the existence of human diseases until the appearance of physical symptoms that are commonly associated with late-stage illness. As a result, it is often too late for successful treatment and survival rates of patients are dramatically reduced. Therefore, the development of diagnostic platforms that accurately identify responsible agents for personalized treatment, and afford an automatic and fast detection, are considered as one of the main targets on improving healthcare systems. Optical biosensors are powerful detection platforms for real-time monitoring of interactions of various biological analytes. Among others, surface plasmon resonance (SPR) sensors have attracted much attention due to direct label-free detection. This talk addresses the development of an innovative sensor platform based on optimized Gaussian optics that combines nanotechnology, biology, electronics and microfluidics to obtain a novel, highly sensitive analytical device for biomedical diagnostics. The major goal is to improve the sensitivity to compete with classical labeling approaches and demonstrate its potential applications in medical diagnostics and therapeutics.
Authors : P.I. Gaiduk, S.L.Prokopyev
Affiliations : Department of Physical Electronics and Nanotechnology, Belarusian State University, prosp. Nezavisimosti, 4, 220030, Minsk, Belarus
Resume : Tin dioxide is widely used in many applications e.g. opto-electronic devices, gas sensors and photovoltaic cells. Sensing properties of SnO2 might be improved by doping with nanoparticles of noble metals which improve chemisorption on the surface and provide a possibility for plasmon-assisted sensing. The idea of this study was to produce SnO2 -Ag nano-composite for gas sensors by using Kirkendall voids as reservoir for noble atoms. SnO2/Ag layers were produced by magnetron sputtering of SnAg alloy layer followed by oxidation. This results in Kirkendall- assisted segregation of silver to nano-particles. A plasmonic-based sensing effect is demonstrated for selective detection of acetone and alcohol in the temperature range of 200-400 °C. The position of the SPR peak in the transmission spectra depends on the SnO2+Ag layer quality and gas exposure. A dynamical response of SnO2+Ag sensor to methane (CH4)/air cycles is measured and sensitivity of the sensor as a function of temperature and light illumination is determined. The concept of plasmonic-based SnO2 sensors is discussed having in mind two main phenomena: First, the ability of metallic nanoparticles to hold plasmonic resonances which depends on the dielectric properties of surrounding SnO2 layer and second, the possibility of space-limited heating of nanoparticles and the neighbouring region with light, and in this way to control the che¬misorption of oxygen on the sensor’s surface.
Authors : Kunli Xiong1, Gustav Emilsson1, Ali Maziz2, Lei Shao1, Edwin W. H. Jager2, Andreas B. Dahlin1*.
Affiliations : 1Chalmers University of Technology, Gothenburg, 41296, Sweden 2Linköping University, Linköping, 58183, Sweden
Resume : Plasmonic nanomaterials provide brilliant colors that arise from the ambient light coupling to the free electrons in metals. In the Roman empire, noble metal nanoparticles were used for staining glass in Church windows and tableware. Thanks to the extra-long lifetime of the plasmonic nanoparticles such glasswork still looks equally bright in color and can thus be used even after thousands of years. In comparison with organic dyes or paints, plasmonic nanomaterials provide strong stable colors even in ultrathin materials (hundreds of nanometers). If the colors can be electrically controlled this provides a novel technology for new display devices. In recent years, reflective (paper-like) displays become more and more interesting since they provides clear images in illuminated environments and are more friendly for human eyes compared to luminous display devices (LED, LCD). One of the most successful commercialized electronic papers is the E-ink technology (e.g. the popular KindleTM). However, one big problem of the E-ink technology on the market is that it only displays monochromatic texts or pictures. It has been known for some time that by implementing electrochemical control over the plasmonic nanostructures one can actively tune the optical response to some extent. Recently, it has also been shown that when combining conjugated polymers with the plasmonic nanomaterials the optical transmission can be modulated with high contrast and fast responding speed. In our work, a novel plasmonic nanomaterial combined with conjugated polymers works as an ?electronic paper? in color with high contrast, fast response time (ms) and ultra-low power consumption (0.5mW/cm2). Especially, by using an ultrathin plasmonic nanostructure with a soft polymer layer the system is highly bendable with ultra-high optical reflection (>90 %), which opens up a new technology for electronic paper applications.
Authors : Tomas Tamulevičius 1,2, Mindaugas Juodėnas 1, Domantas Peckus 1, Lukas Stankevičius 1, Asta Tamulevičienė 1,2, Hongpan Rong 3, Joel Henzie 3, Sigitas Tamulevičius 1,2
Affiliations : 1 Institute of Materials Science of Kaunas University of Technology, K. Baršausko Str. 59, Kaunas LT-51423, Lithuania; 2 Physics department of Kaunas University of Technology, Studentų Str 50, Kaunas LT-51368 Kaunas, 3 National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, 305-0044 Japan
Resume : The plasmonic properties of metal nanoparticles and their assemblies have received great interest in the scientific community because of their unique optical, electrical and catalytic properties. Due to these features, they can be used as components in diverse applications including photonics, optoelectronics, catalysis, photovoltaics and bio-sensing. It is known that plasmonic nanostructures support coherent mechanical oscillations that can be observed with transient absorption spectroscopy (TAS). In this work we examined monodisperse solutions of Ag nancubes and Ag:TiO2 core shell structures with different edge lengths from 40 nm to 100 nm. We observed complex coherent oscillations that indicate the system behaves as a damped oscillator. Fourier analysis of TAS measurements performed over multiple wavelengths shows that the cubes support numerous eigenfrequency modes. The results demonstrate how nanocube length and shell thickness determines the dominant oscillation period (6-35 ps), damping time and Q factor. Thermal expansion analysis was used to examine the continuum dynamics of the nanocubes in the frequency domain using finite element methods. Additionally, regular assemblies of nanocubes were deposited in hexagonal arrays on PDMS templates by employing capillary assisted particle deposition. Dark field optical microscopy demonstrated that number of particles per single trapping site has a big influence on the resonant wavelength and intensity of the scattered light.
Authors : Robert A. Hughes, Eredzhep Menumerov, Spencer Golze, Svetlana Neretina
Affiliations : University of Notre Dame Notre Dame, Indiana 46556, USA
Resume : Exquisite chemical controls are afforded to noble metal nanostructure design when synthesized as colloidal suspensions. This can be attributed to numerous synthetic levers reliant on seed-mediated growth modes, facet-specific capping, an interplay between kinetically and thermodynamically driven processes, and the parametric control offered by such factors as pH, precursor concentrations, and the presence of solvated ions. Efforts to replicate these same growth strategies using substrate-immobilized seeds have proved successful. At the same time, they have opened up new possibilities in terms of establishing auxiliary controls on syntheses that exploit substrate properties. Here, we demonstrate heteroepitaxy as an important synthetic lever in the design of substrate-based noble metal core-shell nanostructures of M@Ag (M = Au, Pt). Periodic arrays of seeds are formed on substrates by defining polycrystalline pedestals of the core material using nanoimprint lithography. These pedestals are then exposed to a heating regimen that causes each to agglomerate into a single-crystal structure whose crystallographic orientation is dictated by whether the substrate material is -, - or -oriented. A liquid-phase redox reaction is then used to deposit the Ag shell onto the core in the presence of a (100) capping agent. With each substrate-orientation giving rise to a unique core-shell architecture with a distinctive polarization-dependent optical response, there exists the potential for heteroepitaxy to emerge as an important synthetic driver in the fabrication of optically active surfaces of noble metal nanostructures.
Authors : Aida Serrano1, Juan Rubio-Zuazo1, Jesus Lopez-Sanchez2, German R. Castro1
Affiliations : 1 Spanish CRG-Spline, The European Synchrotron (ESRF), 38000 Grenoble, France and Instituto de Ciencia de Materiales de Madrid, ICMM-CSIC, 28049 Madrid, Spain; 2 Departamento de Física de Materiales, Universidad Complutense de Madrid, 28040 Madrid, Spain and Unidad Asociada IQFR (CSIC)-UCM, 28040 Madrid, Spain
Resume : Hematite (?-Fe2O3) is an n-type Metal Oxide Semiconductor (MOS), which presents a wide interest in diverse applications such as catalytic and gas sensor. Specifically, the reactive properties of this iron oxide vary as ?-Fe2O3 thin films are supported on substrates with different crystallographic orientation promoting different film growth and crystallinity. Moreover, the catalytic properties of transition metal oxides as ?-Fe2O3 thin films are largely improved in presence of noble metal nanostructures. When they exhibit localized surface plasmon resonance (LSPR), using their ability to absorb and scatter light in the visible part of the electromagnetic spectrum, it is possible to enhance the ?-Fe2O3 features as selective detector for certain gases through electron flow from the metal to n-type ?-Fe2O3 MOS. In this work, we have deposited high quality epitaxial Au/?-Fe2O3 bilayers by Pulsed Laser Deposition (PLD) on two different substrates: STO (111) and ?-Al2O3 (0001). In order to modify the morphological features of the Au top layer the growth temperature of Au is varied ranging from 250 to 750 oC. An exhaustive study of morphological and structural properties of bilayers and the possible formation of other phases at the interfaces has been carried out. For that, several techniques has been employed: Grazing Incidence Surface X-Ray Diffraction (GIXRD), X-ray Photoelectron Spectroscopy (XPS), X-ray Absorption Spectroscopy (XAS) and Atomic Force Microscopy (AFM). Moreover, we present the feasibility of tuning the surface plasmon response associated with Au nanostructures of samples, which is correlated with morphological and structural properties of samples.
Authors : P. Dubček 1, B. Pivac 1, N. Radić 1, N. Krstulović 2 and M. Bišćan 2
Affiliations : 1 Rudjer Boskovic Institute, Bijenicka 54, HR-10000 Zagreb, Croatia 2 Institute for Physics, Bijenicka 46, HR-10000 Zagreb, Croatia
Resume : Plasmonic nanoparticles doping of solar cells improves power conversion efficiency. It is believed that it will be implemented in 4th generation solar cells. The metallic nanoparticles must be incorporated into the cell production, and this limits available annealing temperature range, since the cell is temperature sensitive itself. This leads to compromises in size and shape distribution widths of the plasmonic nanoparticles. Pulsed laser annealing is proposed as a solution: it is limited to the metallic film on top, and the energy for the deweting is supplied to it, leaving the structure below virtually unchanged, regardless the number of applied pulses. Here we report the study of laser annealed aluminium nanoparticle production. Magnetron sputtering at room temperature was employed in production of smooth Al films on monocrystalline silicon. The thickness of films was 10 nm. The films have been annealed by pulsed infra red laser. Pulse energy fluence was varied from 70 to 200mJ/cm2, and the number of pulses from 1000 to 10 000. The size distribution and uniformity of irradiated surface was invrstigated using AFM. The initial film was already nanostructured: its surface is one of densily packed nanopfeatures that are 1.6 nm high. After annealing with 5000 pulses of 120mJ/cm2 energy fluence, larger particles of irregular shape are grown, but they are surrounded by remnants of initial rough surface features. An even distribution of particles was produced when the number of pulses was increased to 10000. Lateral size distribution is significantly sharpened, while the height distribution remains relatively wide. A bimodal particle distribution was produced when th fluence was 150mJ/cm2. Generally, increment of fluence resulted in increased particles height, while the lateral dimensions did not change significantly.
Authors : C. Mennucci1, E. Calandrini2, M.C. Giordano1, A.Toma2,* F. Buatier de Mongeot1,*,
Affiliations : 1 University of Genova, Department of Physics, Genova, 16146, Italy, 2 Italian Institute of Technology, Via Morego 30, I-16163 Genova, Italy
Resume : Self-organized nano-electrodes endowed with broadband plasmonic functionality in the Visible-NIR spectral region, have been employed for both plasmon enhanced photon harvesting and hot electrons collection in a hybrid Au/ Si Schottky junction. The electrode is composed by a self-organized Au nanowire (NW) array, which is formed over cm2 areas in a single maskless step by defocused Ion Beam Sputtering (IBS) of a polycrystalline Au film. The NWs exhibit extremely low sheet resistance values in the range of few Ohm/sq which qualifies them as a valid alternative to commonly used transparent conductive oxide electrodes. Additionally, the optical spectra in transmission show a pronounced dichroism due to the excitation of a broad localized surface plasmon resonance which spans the Vis-NIR spectral range, when light polarization is perpendicular to the NW long axis [1,2]. Particular interest will be focused to the case of a hybrid Au/Ti/Si NW system since the Schottky junction formed at the metal/semiconductor interface allows to collect both carriers photogenerated in Si as well as hot-electrons injected from the Au nanoantennas into Si after non-radiative decay of the plasmon resonance . Knight et al. in their seminal experiment demonstrated the feasibility of IR photon harvesting via injection of hot-electrons produced after the decay of the localized plasmons supported on the Au nanoantennas fabricated by e-beam lithography. Here we demonstrate the feasibility of a large area bottom-up nanopatterning approach which allows to tune the broadband resonance of the Au nanowires in the NIR spectral range, while at the same time ensuring efficient charge transport through the semitransparent front electrode without the use of an auxiliary top electrode based on a transparent conductive oxide layer. Moreover, the preliminary data acquired in the NIR spectral range evidence the presence of a photocurrent signal attributable to plasmon enhanced scattering into the Si substrate and hot-electron injection from the self-organized Au NW electrodes. These results demonstrate that the photon harvesting approach conceived by Knight et al. can be implemented in a single maskless step thus paving the way towards low-cost and large area applications. References  Buatier de Mongeot, F., et al. "Method for the synthesis of an array of metal nanowire capable of supporting localized plasmon resonances and photonic device comprising said array." U.S. Patent No. 8,709,919. 29 Apr. 2014.  Chiappe, D., et al. "Transparent Plasmonic Nanowire Electrodes via Self‐Organized Ion Beam Nanopatterning." Small 9.6 (2013): 913-919.  Knight, Mark W., et al. "Photodetection with active optical antennas."Science 332.6030 (2011): 702-704.
|10:45||Tea Break (10.45-11. 00)|
Carbon Nanomaterials : Yogendra Mishra, Xuanhuva Li
Authors : Hidenori Mimura1, Yoichiro Neo1, Yoku Inoue2 and Katsunori Suzuki3
Affiliations : 1Research Institute of Electronics, Shizuoka University E-mail: firstname.lastname@example.org; 2Department of Electronics and Materials Science, Shizuoka University; 3Research and Development Division, Yamaha Corporation
Resume : Nowadays, nanofibers attract much interest not only in apparel industry, but also information technology, bio-medical, or environmental fields. In the presentation, I will introduce fabrication and characteristics of highly aligned carbon nanotube (CNT) nanofiber sheets [1-4]. The multiwalled CNTs (MWCNTs) were deposited by chloride-assisted chemical vapor deposition. The length of obtained MWCNTs ranges up to the millimeter scale, and they can easily be spun into yarn by hand with the naked eye. The aligned CNT nanofiber sheets were formed by stacking CNT webs drawn from spinnable CNT forest. We have developed strain sensors using the aligned CNT nanofiber sheets . In the presentation, I will review fabrication, characteristics and application of the aligned CNT nanofiber sheets.  Y. Inoue, K. Kakihata, Y. Hirano, T. Horie, A. Ishida, and H. Mimura, Appl. Phys. Lett. 92 (2008) 213113;  Y. Inoue, Y. Suzuki, Y. Minami, J. Muramatsu, Y. Shimamura, K. Suzuki, A. Ghemes, M. Okada, S.Sakakibara, H. Mimura and K. Naito, Carbon 49 (2011) 2437;  A. Ghemes, Y. Minami, J. Muramatsu, M. Okda, H. Mimura, Y. Inoue, Carbon 50 (2012) 4579;  C. Ghemes, A. Ghemes, M. Okada, H. Mimura and Y. Inoue, Jpn. J. Appl. Phys. 52 (2013) 035202;  K. Suzuki, K. Yataka, Y. Okuyama, S. Sakakibara, K. Sako, H. Mimura and Y. Inoue, ACS sensors (2016) 817.
Authors : Dawid Janas
Affiliations : Department of Organic Chemistry, Bioorganic Chemistry and Biotechnology, Silesian University of Technology, B. Krzywoustego 4, 44-100 Gliwice, Poland
Resume : Ever since first carbon nanostructures were synthesized and revealed their remarkable properties, the R&D community has worked on their utilization in real-life scale applications. One of the major impediments however is the translation of the impressive nanoscale performance onto macroscopic objects. Carbon nanotubes and graphene assembled into films and fibers are often unable to meet the expectations. The problems are mainly caused by the lack of necessary control over their structure. The inability to form appropriate contact between individual carbon nanotubes or graphene flakes prohibits efficient transfer of stress, phonons, electrons, etc. Another key factor is the indiscriminate nature of the synthesis methods, which results in formation of plurality of carbon nanostructures. As-made mixture of carbon nanotubes, with many of various atom arrangement (referred to as chiral angle) gives inferior properties and makes the material unsuitable for certain applications. In this contribution, the results of work on formation of macroscopic objects of highly-defined nanostructure based on carbon nanotubes are presented. It is demonstrated how careful control at the atomic level can design the material for a foreseen application.
Authors : Júlia Kleinpaul, Rafaela Alberti Pagnussati, Helena R. Arede, Ricardo Paupitz, Andre Muniz
Affiliations : Department of Chemical Engineering, Federal University of Rio Grande do Sul (UFRGS), Brazil; Department of Chemical Engineering, Federal University of Rio Grande do Sul (UFRGS), Brazil; Department of Chemical Engineering, Federal University of Rio Grande do Sul (UFRGS), Brazil; Institute of Geosciences and Exact Sciences, Sao Paulo State University - UNESP, Brazil; Department of Chemical Engineering, Federal University of Rio Grande do Sul (UFRGS), Brazil
Resume : As a development of our previous work regarding the so called Porous Fullerenes (Phys. Chem. Chem. Phys., 2014, 16, 25515), we investigate the possibility of assembling these closed cage molecules in order to construct nanostructured patterns. In this work we investigate the stability, geometry and electronic structure of one-dimensional and two-dimensional patterns formed by porous fullerenes. Our results indicate that different sites can be used to obtain the chemical bonds between close packed porous fullerenes. Furthermore, each pattern can lead to different electronic properties, namely the structure can become a semiconductor, a metal or an electrical insulator depending on the connection between each closed cage molecule and its nearest neighbors. In other words, the electronic properties are highly dependent on the repeating unit used and on the specific connecting sites considered to construct the superstructure. The stable configurations found for the nanostructured patterns are also highly porous, a characteristic that poses these new materials as possible candidates as nanosieves, for example. Other possible application under investigation is the possible ability of these nanostructures to encapsulate small molecules.
Authors : Irina Plesco1*, Julian Strobel2, Fabian Schütt2, Leonid Gorceac3, Boris Cinic3, Cameliu Himcinschi4, Yogendra Kumar Mishra2, Lorenz Kienle2, Rainer Adelung2, Ion Tiginyanu1
Affiliations : 1National Center for Materials Study and Testing, Technical University of Moldova, Stefan cel Mare av. 168, MD-2004, Chisinau, Republic of Moldova 2 Institute for Materials Science, Christian Albrechts University of Kiel, Kaiserstr. 2, D-24143 Kiel, Germany 3Department of Physics and Engineering, State University of Moldova, str. Alexei Mateevici 60, Chisinau, MD-2009 Republic of Moldova 4TU Bergakademie Freiberg, Institute of Materials Science, Gustav-Zeuner-Strasse 5, D-09596 Freiberg, Germany
Resume : Over the last years considerable attention has been paid to the development of flexible nanocomposite materials based on carbon aerogels decorated by semiconductor micro-nanoparticles. In particular, three-dimensional architectures of GaN and ZnO micro-nanocrystallites deposited on Aerographite scaffolds have been proposed for multifunctional applications [1,2], while graphene aerogels decorated by GaN or SnO2 nanocrystalline thin films have been successfully used to fabricate ultra-lightweight flexible pressure sensors, which are promising for applications in automotive and aeronautic industries . In this work, we report on fabrication and characterization of flexible hybrid materials based on InP:Zn micro-nanostructures deposited on Aerographite scaffolds by using hydride vapor phase epitaxy. Depending on the technological conditions, InP:Zn micro-nanocrystallites and/or InP:Zn micro-nanowires were found to grow on Aerographite, leading to the formation of a three-dimensional hybrid architecture. Due to the high porosity of the Aerographite network, with pores up to several µm in diameter, the growth of indium phosphide micro-nanocrystallites takes place all over the 3D scaffold. On top of that, some crystals also tend to grow at the inner surfaces of the graphitic microtubes constituent. Characterization of the samples by using Transmission Electron Microscopy and Energy Dispersive X-ray analysis disclosed the zinc-blend type lattice and chemical composition corresponding to indium phosphide. Besides, the crystalline quality of both InP crystallites and wires was proved by Raman scattering spectra which were dominated by the TO (303 cm-1) and LO (344 cm-1) vibrational modes. A model for the growth of InP micro-nanostructures on Aerographite template is proposed and possible applications of the developed composite material are discussed.  I. Tiginyanu et al, Sci. Rep. 6, 32913 (2016);  A. Schuchardt et al, Sci. Rep. 5, 8839 (2015);  M. Dragoman et al Nanotechnology, Vol. 27, 475203 (2016).
Authors : F. Schütt,1* D. Smazna,1* V. Postica,2 O. Lupan,1,2* Y. K. Mishra,1 R. Adelung1
Affiliations : 1 Functional Nanomaterials, Institute for Materials Science, Kiel University, Kaiserstr. 2, D-24143, Kiel, Germany 2 Department of Microelectronics and Semiconductors Devices, Technical University of Moldova, 168 Stefan cel Mare Av., MD-2004 Chisinau, Republic of Moldova
Resume : Among all type of semiconducting oxides, zinc oxide is the most investigated material with an exceptional variety of applications, especially with respect to its 3D tetrapodal (T) morphology. Hybrid and porous materials attracted a great attention from the scientific community in the field of environmental gas sensing applications. Recently, we demonstrated a novel method for the hybridization of highly porous 3D ZnO networks synthesized by flame transport synthesis (FTS) by a simple wet chemical nanoparticle infiltration, allowing for the fabrication of hybrid nano-micro-crystals, e.g. ZnO-T-CNT. In this research, CNTs-functionalized ZnO-T tetrapodal networks (ZnO-T−CNT) demonstrated excellent room temperature ammonia vapor sensing performances with high selectivity and sensitivity. The influence of CNT content in the networks was investigated. ZnO-T−CNT networks with 2.0 wt% of CNTs showed an increase of about one order of magnitude in gas response compared to pristine networks. The gas sensing mechanism was proposed based on the high porosity of the used 3D networks and the good conductivity of the CNTs, which facilitate the electron transport between the materials, as well as the excellent room temperature sensing properties of CNTs to ammonia molecules. On top of that, an improvement in ultraviolet sensing was observed, based on the separation properties of photogenerated electron-hole pairs in the ZnO-CNT hybrid nanomaterial. Thus, the fabricated multifunctional ZnO-T−CNT networks will allow for the detection of ammonia at room temperature, with applications in environmental monitoring, chemical industry, and biomedical diagnostics.
Authors : Tricard S., Saïd-Aïzpuru O., Bouzouita D., Usmani S., Gillet A., Tassé M., Poteau R., Viau G., Demont P., Carrey J., Chaudret B.
Affiliations : LPCNO, INSA, CNRS, Université de Toulouse, 31077 Toulouse, France; LCC, CNRS, Université de Toulouse, 31077 Toulouse, France; Institut Carnot ? CIRIMAT, Université de Toulouse, 31062 Toulouse, France.
Resume : Even if Coulomb blockade has been studied for over sixty years, and previously observed at room temperature, the new concept of our work is its fine modulation, which can only be achieved by a controlled organometallic chemistry approach, as a first step toward electronic devices. The goal is to tune Coulomb blockade in dense three-dimension self-assemblies of metallic nanoparticle with simple chemical tools. Synthesizing robust systems ? stable in air for months ? is a crucial condition; platinum nanoparticles stabilized by thiols, which form strong Pt-S bonds, are thus suitable systems. This presentation will describe the first system where the nanoparticle size, the ligand length and the ligand dielectric constant are independently varied to control the nanoparticle charging energy. Such a chemical approach allowed the determination of the most important parameters that influence Coulomb blockade, namely the dielectric constant of the ligands and the size of the nanoparticles. Elaborating such systems, stable in air for months, is a first step towards nanoelectronic systems, where the charging energy of the nanoparticles is tuned by the nature of the ligands.
Authors : Dr. Mohammed Palashuddin Sheikh
Affiliations : Assistant Professor, Department of Chemistry, Aligarh Muslim University, Aligarh-202002, Uttar Pradesh, India
Resume : This work demonstrates that Cu2+ embedded carbon nanoparticles (Cu-CNP) acts as an anticancer agent. The fluorescent Cu-CNP was synthesized by using carbon nanoparticles and copper salt at 500C (pH=9-11). The formation of Cu-CNP was established using UV-visible spectroscopy, fluorescence spectroscopy, IR spectroscopy, powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies. The average size of the Cu-CNP was found to be 92.7 ± 49.8 nm. The cell viability study in presence of Cu-CNP was carried out by standard MTT assay followed by cell cycle analysis, where the cells have been found to undergo apoptosis. Also, generation of reactive oxygen species in the cell, in the presence of the composite nanoparticles, has been attributed to their killing. In this regard, the blue emission of Cu-CNP could be used to monitor the cellular uptake by confocal microscopy. Overall, good biocompatibility, bright emission, cellular imaging application, and anticancer effect of Cu-CNP will make it a promising candidate for future theranostic applications. Reference: 1. Cu2+-embedded carbon nanoparticles as anticancer agents. Sk, M. P.; Goswami, U.; Ghosh, S. S.; Chattopadhyay, A. J. Mater. Chem. B 2015, 3, 5673.
Authors : Tudor Braniste, Ion Tiginyanu; Simion Raevschi; Tibor Horvath, Birgit Andrée, Serghei Cebotari, Erin C. Boyle, Axel Haverich, Andres Hilfiker;
Affiliations : National Center for Materials Study and Testing, Technical University of Moldova, Stefan cel Mare av. 168, MD-2004, Chisinau, Republic of Moldova; Department of Physics and Engineering, State University of Moldova, str. Alexei Mateevici 60, Chisinau, MD-2009 Republic of Moldova; Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl Neuberg Str. 1, D-30625 Hannover, Germany
Resume : In this study, porcine aortic endothelial cells were investigated in direct contact with Gallium Nitride (GaN) based nanoparticles. GaN is a compound semiconductor material, with remarkable characteristics including piezoelectric properties, high thermal stability, radiation hardness and excellent chemical inertness, which make it promising for biomedical applications. There is, however, limited knowledge about the biocompatibility of nanostructured GaN and the impact of GaN nanoparticles on living cells. We report on growth and characterization of GaN/ZnFe2O4 multifunctional piezoelectric and magnetic nanoparticles as well as on their assimilation and interaction with living endothelial cells. Thin GaN layers were grown on ZnO and ZnFe2O4 nanoparticles with sizes ranging from 50 to 100 nm, using Hydride Vapor Phase Epitaxy (HVPE). After GaN growth, the ZnO sacrificial core of nanoparticles was decomposed at high temperatures in hydrogen flow, the final composition of nanoparticles corresponding to GaN:Fe. The resulted nanoparticles were incubated with living endothelial cells in order to remotely influence the cells activity through nanoparticles. By cultivating cells in medium supplemented with different concentrations of nanoparticles, we show that endothelial cells are tolerated by GaN nanoparticles much better than by ZnO nanoparticles of the same size . Transmission Electron Microscopy (TEM) demonstrates that GaN-based nanoparticles are assimilated by endothelial cells, and the cellular proliferation is not affected. The obtained results show that, being uptaken by the cells, the GaN nanoparticles are deposited into vesicles and thus can be used as guiding elements for controlled transportation or designed spatial distribution of cells in a magnetic field, which represent a step forward towards application in cellular therapy. . Tudor Braniste, Ion Tiginyanu, Tibor Horvath, Simion Raevschi, Serghei Cebotari, Marco Lux, Axel Haverich, Andres Hilfiker. Viability and proliferation of endothelial cells upon exposure to GaN nanoparticles. Beilstein Journal of Nanotechnology, 2016, 7, 1330-1337
Multifunctional Composites : Yogendra Mishra, Ion Tiginyanu
Authors : An?l ?NCEL, Mustafa M. DEM?R
Affiliations : ?zmir Institute of Technology Department of Materials Science and Engineering 35430 ?zmir, Turkey email@example.com
Resume : Majority of crystalline materials, particularly polar and noncentrosymmetric ones, extibit bright light emission upon application of mechanical force. This phenomenon is called triboluminescence (TL). These crystals are usually in the powder form and need to be associated with polymeric systems to achieve processibility in complex shaped sensor platforms. In this study, two different colors of TL crystals, EuD4TEA and Cu(NCS)(py)2(PPh3), were synthesized and integrated into various polymeric systems such as PMMA, PS, PU, and alginate for different end-use such that films from blending or surface impregnation, fibers by electrospining, and beads by polymer gelation. TL and PL emission spectra of the composite systems usually showed similar behavior. In processing of any type, when the crystals are molecularly dissolved, TL feature cannot be observed. TL signal can be achieved if the TL materials preserve their crystal form. Surface impregnation allowed to achieve meaningful TL signal even at low concentration of the crystals with respect to polymer matrix. Among the polymers employed, PU was found to be the most promising matrix due to its chemical affinity for the both crystals. PU expires with long-lived emission, and maximum TL response with respect to applied force between 2.45 and 42.0 N. It also offers a high quantum yield, long-lived detectable TL response, and higher PL efficiency. *This project is supported by TUBITAK (KBAG 114Z292).
Authors : Ayyaan Khan1, B. S. Sikarwar* 2, Yogendra K. Mishra,3 Rainer Adelung,3 D.K. Avasthi1
Affiliations : 1Amity Institute of Nanotechnology, Amity University, Uttar Pradesh, Noida-201313, India *2 Department of Mechanical Engineering, Amity University, Uttar Pradesh, Noida- 201313, India, firstname.lastname@example.org 3Functional Nanomaterials, Institute for Materials Science, Kiel University, Kaiserstr. D-24143, Kiel, Germany
Resume : Thermal energy storage in form of latent heat using Phase change material (PCM) have been area of research for the last three decades. Paraffin wax is more appropriate PCM for storing energy in form of latent heat because of favorable thermos-physical properties such as high density, specific heat and latent heat of fusion. However, its thermal conductivity posed a continuously challenge in its large-scale deployment. In this work, the thermal conductivity of paraffin wax is altered using Carbon nano-tube (CNT) and ZnO nano-fillers, aiming to improve the thermal conductivity of paraffin wax. The CNT and ZnO were stirred in liquid wax at 60 oC with CNT and ZnO doping level 0.05, 0.1 and 0.2 wt%. The experimental results show the thermal conductivity of tailored paraffin wax increases as CNT and ZnO loading contents. Both CNT and ZnO enhance the thermal conductivity of tailored wax, while ZnO is more effective than CNT as the thermal conductive filler because of its better dispersion in the wax. The melting dynamics is simulated with computational fluid dynamics for the understanding the behavior of the composite of wax with nanofillers.
Authors : Florent Pourcin, Miriam Carlberg, Judikaêl Le Rouzo, Rose-Marie Sauvage, Gérard Berginc, Olivier Margeat, Ludovic Escoubas, Jörg Ackermann
Affiliations : F. Pourcin; Dr. O. Margeat; Prof. J. Ackermann; Aix Marseille Univ, CNRS, CINaM, Marseille, France M. Carlberg; Dr. J. Le Rouzo; Dr. L. Escoubas; Aix Marseille Univ, Université de Toulon, CNRS, IM2NP, Marseille, France Dr. G. Berginc; Thales Optronics, Elancourt, France Dr. R.-M. Sauvage; DGA/DS/MRIS, 75015 Paris, France
Resume : Plasmonic nanoparticles are an interesting class of metallic nano-objects thanks to their unique optical properties. The light absorption, reflection and scattering depend on different parameters such as size, shape, material and environment of the particles. Moreover, when these nanoparticles are embedded in a transparent polymer matrix, new hybrid materials are obtained with enhanced and/or tunable optical properties which are different from those of the individual nanoparticles1. Collective effects arising from nanoparticle coupling in the layer are indeed of primary importance in thin films elaborated from these hybrid materials. In this work, the aim is to obtain a perfect absorber in the visible range by controlling the optical properties of such hybrid materials, which has several applications related to stealth technologies, photodetectors and solar cells. In this context, we propose a method for generating a stack of thin layers of hybrid materials with tunable optical properties, based on controlling the dispersion and the aggregation state of the nanoparticles within the non-absorbing polymer matrix. We focus the study on silver nanocubes since they possess a strong high electric field enhancement over the whole domain of the visible region. We propose a method to tune the nanocubes density and the organization of the nanoparticles within the layer in order to strongly modify the absorption and the reflection properties of these materials without changing its composition. This study opens the way towards simple processable methods to modify the optical properties of hybrid materials in thin films. 1 Carlberg, M; Pourcin, F; Margeat, O; Le Rouzo, J; Berginc, G.; Sauvage, R.-M; Ackermann, J; Escoubas, L Beilstein J.N. 2017
Authors : Giovanni Manfredi, Paola Lova, Francesco Di Stasio, Roman Krahne, Davide Comoretto
Affiliations : Dipartimento di Chimica e Chimica Industriale, Università degli studi di Genova, Genova, Italy; Dipartimento di Chimica e Chimica Industriale, Università degli studi di Genova, Genova, Italy; Nanochemistry Department, Istituto Italiano di Tecnologia, Genova, Italy; Nanochemistry Department, Istituto Italiano di Tecnologia, Genova, Italy; Dipartimento di Chimica e Chimica Industriale, Università degli studi di Genova, Genova, Italy
Resume : Planar photonic crystals are interesting structures suitable for many applications, including sensing and lasing. The use of polymers as structural materials in these systems allows to obtain simple processability and scalability of production. Moreover, the properties of photoactive materials inside photonic crystals are still topics under investigation and the study of micro and nanostructured cavities is an interesting research subject in scientific community. Also nanostructuring on much smaller scale is currently a well-studied subject and nanoparticles gives the possibility to obtain materials having tuned optical responses. This kind of photoactive particles can then be integrated inside nanocomposites to obtain process-able hybrid materials. In this work, we present the production and study of the optical properties of hybrid planar microcavities entirely created by spin-coating. The passive photonic crystal backbone is given by polymers while the active material is given by CdSe/CdS nanocrystals used as they are or embedded inside a nanocomposite. We report on strong directional fluorescence enhancement properties and changes in lifetimes induced by the photonic environment. Moreover, clear lasing effects are shown and discussed when suitable photoactive materials are selected, proving the possibility of using these systems as low power lasing devices.
Semiconductor Nanostructuring : Yogendra Mishra, Oliver Schmidt
Authors : Y. Berencén1,*, S. Prucnal1, M. Wang1, R. Hübner1, R. Böttger1, M. Glaser2, T. Schönherr1, W. Möller1, Y. M. Georgiev1, L. Rebohle1, A. Erbe1, A. Lugstein2, S. Zhou1, M. Helm1 and W. Skorupa1
Affiliations : 1Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden, Germany 2Institute for Solid State Electronics, Vienna University of Technology, Floragasse 7, A-1040 Vienna, Austria
Resume : The hyperdoping of semiconductors consists of introducing dopant concentrations far above the equilibrium solubility limits. This results in a broadening of dopant energy levels into an impurity or intermediate band. We have recently demonstrated that hyperdoping bulk Si with Se shows promise for Si-based short-wavelength infrared photodetectors . Lately, silicon nanowires (NWs) have gained increasing importance as building blocks for nanodevices like field-effect transistors, light emitting devices and photovoltaic cells [2, 3]. Therefore, the comparison between hyperdoping Si nanowires and bulk Si is a common issue to be examined, which comes along with the transition from a bulk material to semiconductor NWs. In this work, we report on non-equilibrium processing for controlled hyperdoping of Si/SiO2 core/shell nanowires previously synthesized by the vapor-liquid-solid method. Our approach is based on Se implantation of the upper half of NWs followed by millisecond flash lamp annealing, which allows for a bottom-up template-assisted recrystallization of the amorphized parts of the NWs via explosive solid-phase epitaxy. The Se-hyperdoped Si NWs are successfully recrystallized and accommodate Se concentrations as high as 1021 cm-3. As a proof of device concept, a single Se-hyperdoped NW-based IR photoconductor is shown. In this way, the combination of ion implantation and flash lamp annealing as a promising nanoscale hyperdoping technology is successfully established.  Y. Berencén, S. Prucnal, Fang Liu, I. Skorupa, R. Hübner, L. Rebohle, S. Zhou, H. Schneider, M. Helm, and W. Skorupa, “Room-temperature short-wavelength infrared Si photodetector,” Sci. Rep. 7, 43688 (2017).  B. Tian, T. Cohen-Karni, Q. Qing, X. Duan, P. Xie and C.M. Lieber, “Three-dimensional, flexible nanoscale field-effect transistors as localized bioprobes,” Science 329, 831 (2010).  T. J. Kempa, B. Tian, D.R. Kim, J. Hu, X. Zheng and C.M. Lieber, “Single and tandem axial p-i-n nanowire photovoltaic devices,” Nano Lett. 8, 3456 (2008). *Corresponding author: email@example.com
Authors : F. Lafond (1 2 3), Ph. Baranek (1 2 3), A. Postnikov (4)
Affiliations : (1) EDF R&D, Department Economic and Technical Analysis of Energy Systems (EFESE), EDF Lab ? Chatou, 6 quai Wattier, F-78400 Chatou Cedex, France ; (2) Institut of Research and Development on Photovoltaic Energy (IRDEP), UMR 7174 CNRS/EDF R&D/Chimie ParisTech ? PSL, 6 quai Wattier, F-78400 Chatou Cedex, France; (3) Institut Photovoltaïque d?Ile de France (IPVF), 8 rue de la Renaissance, F-92160 Antony, France; (4) University of Lorraine, Jean Bariol Institute, Laboratoire de Chimie et Physique ? Approche Multi-échelle des Milieux Complexes (LCP-A2MC), 1 Bd Arago, F-57078 Metz, France
Resume : The electrical properties of semiconductors, such as concentrations and mobilities of the charge carriers therein, are strongly influenced by the types of dopants and defects inserted or formed during the synthesis of materials. In the context of photovoltaics, the doping is typically an intentional process that permits to tune different properties of solar cells. Meanwhile, the presence of intrinsic defects, like vacancies or dislocations, is difficult to control, that might eventually result in degrading the efficiency and durability of solar cells. Such effects are largely temperature dependent, since the defect formation energies are substantially related to lattice vibrations. Within the first-principles theory, the effect of temperature can be grasped within the quasi-harmonic approximation; however, the precise numerical predictions may vary depending on the accuracy of exchange-correlation functionals and the size of the supercells used. We report the results of a comparative study, by means of the density functional theory, of hybrid functionals, under an angle of the latter?s performance in the assessment of temperature variation of thermodynamic properties. Specifically we study silicon doped with carbon and germanium and/or otherwise containing point defects. The reliability of this approach to determine the structural, electronic and dynamic properties of the different systems will be discussed.
Authors : Magnus Dahl, Luna Namazi, Reza R. Zamani, Kimberly A. Dick
Affiliations : Solid State Physics, Lund University, Box 118, SE-22100 Lund, Sweden; Solid State Physics, Lund University, Box 118, SE-22100 Lund, Sweden; Solid State Physics, Lund University, Box 118, SE-22100 Lund, Sweden; Solid State Physics, Lund University, Box 118, SE-22100 Lund, Sweden AND Centre for Analysis and Synthesis, Lund University, Box 124, 221 00, Lund, Sweden
Resume : III-V nanowires have been proven to be excellent platforms for studying the fundamental physics of semiconductors as well as potential candidates for future electronic and optical devices. Ternary compound V-III nanowires are interesting due to the possibility of modulating their physical and material properties by tuning their material composition. Amongst them InAs1-xSbx nanowires are good candidates for Infrared detectors. In addition, branched nanowire structures from III-V semiconducting material are good templates for studying phenomena such as Majorana fermions. InAs and InAs1-xSbx material systems are best suitable for these studies due to the high carrier mobility they have and also the large g factor they offer. Moreover, the compositional tunability of InAs1-xSbx leads to tuning the band gap in the mid infrared region. Therefore, this material is a good candidate for IR detection. Having access to branched nanowires of these materials will lead to more absorption, hence a better detection ability. In addition, most III-V nanowires grow both in the zinc blende and metastable wurtzite crystal structure. It has been demonstrated that the crystal structure of these nanowires can be precisely controlled for different materials such as InAs. Furthermore, the physical properties a material system exhibits is largely dependent on the crystal structure it has. Antimonide based nanowires however, do not prefer growing in the wurtzite crystal structure as a consequence of the surfactant effects of Sb, and the general trend of lower ionicity of III-Sb compounds. It has been demonstrated previously, that by adding a small amount of Sb to InAs, the crystal structure of the nanowire can be altered to zinc blende. Therefore, the properties of antimonide nanowires in the wurtzite crystal structure are yet to be studied. As growing reasonably long axial segments of antimonides prove to be challenging, we here demonstrate successfully utilizing another approach for accessing wurtzite InAs1-xSbx nanowires. For this purpose, we deposite secondary Au-seed particles on already grown wurtzite InAs nanowires, and attempt growing InAs1-xSbx branches by means of Metal organic vapor phase epitaxy (MOVPE). As expected, the epitaxially grown branch will transfer the underlying crystal structure of the wurtzite InAs trunk. We study the effect of varying the Sb vapor phase composition on the crystal structure, and the solid phase composition of the grown nanowire branches, while comparing them to branches grown simultaneously on zinc blende InAs trunk nanowires. We also demonstrate that, the wurtzite branches tend to form in relation to occasional stacking defects along the InAs trunk, transferring the stacking fault into the branch. We also discuss the existence of a hard limit for the Sb incorporation in the wurtzite branches as opposed to their zinc blende counter parts.
Authors : M I Shishkin, A G Rokakh
Affiliations : Department of Semiconductors Physics, Saratov State University, Saratov 410012, Russia
Resume : Allowing for plasma resonance of charge carriers, numerical simulation of reflection spectrum is done for polycrystalline film of limited solid solution CdS(0,9)-PbS(0,1) described as system of PbS inclusions in CdS matrix. Comparison of calculated spectrum with experimental reflection spectra of annealed and unannealed films with same composition is carried out.
Authors : Bartłomiej Seredyński, Mateusz Król, Piotr Starzyk, Rafał Mirek, Daniel Stephan, Jacek Szczytko, Barbara Piętka, Wojciech Pacuski
Affiliations : Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
Resume : Monocrystalline substrate is a key component for growth of thin layers by molecular beam epitaxy (MBE). The choice of the substrate is typically determined by the lattice constant and crystalline structure of the designed layer. However physical properties of substrates may significantly affect the experiments performed on epitaxial layers, e.g. opaque substrate limits the light transmission and contributes to the absorption. The problem of opaque substrate can be solved by a lift-off of epitaxial layers. The purpose of this work was to develop and verify a new method of producing free-standing semiconductor microcavities containing semi-magnetic (Cd,Zn,Mn)Te quantum wells (QW). On the GaAs substrate the 1 m thick CdTe buffer and 1 m MgTe layer were deposited. The MgTe layer was introduced here for the first time and is of particular importance. The structure is followed by 22 pairs of Bragg mirror based on (Cd,Zn,Mg)Te with 40% and 8% of Mg in low and high refractive index layers, respectively. The width of layers was optimized to reach cavity resonance at emission wavelength of QWs (about 760 nm). Inside λ cavity we have grown three (Cd,Zn,Mn)Te QWs containing about 0.3% of manganese. Finally we have grown 22 pairs of top Bragg mirror. Except of MgTe buffer the structure was similar to the first exciton-polariton sample based on (Cd,Zn,Mg)Te . Despite hygroscopic MgTe layer, our structure is stable in ambient atmosphere. Reflectance, at both room and helium temperatures, shows characteristic stopband with sharp cavity mode interacting with a QW excitons and forming exciton-polaritons. To separate the microcavity epitaxial layer from the rest of the structure, the sample was glued to a quartz glass and immersed in a deionized water for 2 hours. After rinsing, MgTe layers was removed by water and the glass plate with microcavity containing QWs was lifted-off from the substrate . The images of the sample on the glass shows continuous surface of the area exceeding 10 mm2. Low temperature photoluminescence and reflectivity spectra of the microcavity demonstrate the existence of strongly coupled exciton-polariton modes, what confirms that Mg in Bragg mirror and cavity was not harmed despite long contact with water. Only after lift-off it was possible to measure optical transmission through the microcavity. The observation of lower and upper polaritons is consistent with the results obtained using other experimental configurations, such as back illuminated photoluminescence or angle resolved reflectivity. Moreover, the magnetooptical measurements allow us to observe giant Zeeman effect of polaritons, observed previously only on non-transmitting microcavities . Our new design of microcavity structures opens possibility of experiments on resonantly excited exciton-polariton superfluids with magnetooptical properties enhanced by the presence of Mn in quantum wells.
Authors : Karolina Po?czy?ska, Wojciech Pacuski
Affiliations : Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
Resume : Design of our distributed Bragg reflector (DBR) is quite different from II-VI DBRs grown so far. Firstly, our DBR does not include magnesium, so it is not hygroscopic and it should be stable for years even outdoor, what can be important e.g. in solar cells applications. Secondly, composition of our DBR is relatively simple, there are only two elements in each layer, what makes the growth process much easier. Interestingly, the layer with lower refractive index is also that one with lower energy gap. It is exceptional situation, because usually semiconductors with high energy gap has low refractive index, which is not true for ZnTe (Eg = 2.4 eV, n ~ 2.9) and CdSe (Eg = 1.7 eV, n ~ 2.6). Consequently, refractive index difference (crucial parameter for DBRs) is increasing for long wavlenth and decreseing close to energy gap short wavelength, what is unusual for semiconductor DBRs. From practical point of view it is importnant that both materials have similar lattice constant, which is 6.08 Å for ZnTe and 6.05 Å for CdSe. Difference in refractive indexes and corresponding lattice constants makes ZnTe and CdSe perfect materials for making a Bragg reflector for infrared spectral region. We realize our DBR using molecular beam epitaxy (MBE) assisted with in-situ reflectivity. On top of 3 inch large GaAs:Si (100) substrate we grew 30 pairs of CdSe and ZnTe, each layer with a thickness of ?0/4n. We obtained reflectance over 95% for ?0>900nm. We conclude that design of our DBR will be even more efficient for even longer wavelength ?0 > 1000 nm, in particular for telecom wavelength.
Authors : T. Michaud, S. De Sousa Nobre, T. Baffie, S. Desrousseaux, L. Aixala, J.-P. Simonato
Affiliations : University Grenoble Alpes, CEA/LITEN/DTNM, MINATEC Campus, F-38054 Grenoble, France
Resume : Thanks to the “low temperature joining technique ” , it is possible to replace lead soldering joints with metallic nanoparticles-based pastes. The specific surface area of these nanoparticles is so high that their sintering and melting temperatures are lowered compared to microparticles. For example, silver nanoparticles are sintered at about 300°C, to have a final joint with the same melting temperature as bulk silver (962°C). Copper based nanoparticles are a good candidate to replace silver due to the relatively low cost and high thermal conductivity of copper. However, under air, copper nanoparticles oxidize faster than raw copper, the oxidation being a surface phenomenon. One way to protect the nanoparticles from oxidation is coating them with a silver shell by galvanic displacement and displacing the oxidation starting point to higher temperatures  . In this work, we will present the synthesis by oxidation-reduction reactions in a polyol medium of Cu nanoparticles and Cu@Ag core-shell nanoparticles, control of nanoparticles diameter and respective characterization (TEM-EDS, XRD…). We will focus our study on the oxidation phenomena for Cu and Cu@Ag core-shell nanoparticles by thermogravimetric analysis (TGA). The silver coating was either performed in one step (by galvanic displacement) or in two steps (by galvanic displacement and growth of a thicker layer). From TG curves it is possible to identify two different oxidation regimes. References:  G. Bai, “Low-Temperature Sintering of Nanoscale Silver Paste for Semiconductor Device Interconnection” (Virginia Tech, 2005)  A. Pajor-Świerzy et al., “Air Stable Copper-Silver Core-Shell Submicron particlesSynthesis and Conductive Ink Formulation,” Colloids and Surfaces A: Physicochemical and Engineering Aspects 521 (2017): 272–80
Authors : J. Rodrigues*, N. Ben Sedrine*, A. F. Martins*, J. F. C. Carreira*, D. Smazna**, J. Gröttrup**, O. Lupan**, R. Adelung**, Y. K. Mishra**, M. R. Correia*, T. Monteiro*
Affiliations : *Departamento de Física e I3N, Universidade de Aveiro, Campus Universitário de Santiago,3810-193 Aveiro, Portugal; **Functional Nanomaterials, Institute for Materials Science, Kiel University, Kaiser str. 2, D-24143, Kiel, Germany
Resume : Hybrid nanostructures from metal oxides have received much attention due to the ability to tune their physical properties giving rise to enhanced functional materials. Depending on type of added material, different mechanisms and functionalities can be induced. In this work, the optical properties of zinc oxide based hybrid tetrapodal (ZnO-T) networks produced by flame transport synthesis were investigated. Hybrid ZnO-T 3D network materials with different metal oxides (MexOy) and ternary alloyed systems (ZnxMe1-xOy) were synthesized and highly crystalline pure ZnO-T 3D networks were covered with previously formed clusters of single C60 molecules. Optical studies were performed in order to evaluate the presence of bulk and surface defects, as well as the balance between the recombination/trapping of photogenerated carriers on these nanostructures. Photoluminescence (PL) measurements revealed that a deep level visible emission was present for all the samples, with intensity considerably higher than the near band edge (NBE) emission (at room temperature). The spectral shape of the PL emission was found to be sample dependent, suggesting that the visible PL is due to an overlap of emitting centres, likely originated from the incorporation of metal ions (e.g., Fe) in the ZnO matrix plus the MexOy and ZnxMe1-xOy phases present. For the samples with C60, besides the NBE and visible PL, an emission at higher energies than the ZnO bandgap was seen to appear in samples with lower C60 floodings, probably originated from the composite matrix. Moreover, samples with higher C60 floodings exhibited steeper absorption in the ZnO bandgap accompanied with well-resolved free exciton recombination revealing distinctive surface/interface behaviour when compared with samples covered with lower C60 content.
Poster Session : YKM, IT, JA, OGS
Authors : Kyong-Hoon Choi, Sang-Yoon Lee, Bong Joo Park, Jin-Seung Jung
Affiliations : Kwangwoon University; Gangneung-Wonju National University
Resume : Over the last few decades, photosensitizer (PS)-mediated photodynamic therapy (PDT) has been introduced as a possible alternative non-invasive localized therapeutic modality for treating cancer as well as cardiovascular, ophthalmic, dermatological, and dental diseases. PDT is a two-step procedure that involves the administration of a photosensitizing agent, followed by activation of the drug with non-thermal light of a specific wavelength. In particular, this photodynamic process rapidly generates reactive oxygen species (ROS), including peroxides, hydroxyl radicals, superoxide ions, and singlet oxygen, with the latter implicated as the major causative agent of cellular damage in the photodynamic process. However, the results of recent clinical and preclinical studies of PDT indicate that this process still suffers from disadvantages such as the wavelength-dependent tissue penetration depth of the light, inefficient delivery of PS to the target area, loss of PDT efficacy due to aggregation, degradation, or reduction of PSs; and toxicity of the PS. Several approaches have been proposed to enhance the efficacy of PDT. In some cases, PDT efficacy was found to be significantly improved when nanoparticles were applied as PS carriers, suggesting that the use of nanoparticles can help to overcome the aforementioned limitations. Among the various nanoparticles available, such as liposomal vesicles, quantum dots, nanotubes, and gold nanoparticles, the latter have attracted substantial attention, because of their chemical inertness, excellent optical properties, and minimal biological toxicity. To improve the PDT efficacy, it is also important to understand the photophysical and photochemical properties of as-prepared photosensitizing agents. In particular, the illumination parameters might play an important role in PDT efficacy. Herein, we report the development of new multifunctional magnetic nanoparticles conjugated with hematoporphyrin (HP) and folic acid (FA) (CoFe2O4-HPs-FAs) for use as potential PDT agents, which were tested by targeting prostate cancer PC-3 cells with FA. The biocompatibility and photodynamic anticancer activity of the CoFe2O4-HPs-FAs were evaluated in vitro. In addition, we evaluated the effect of variations in the fluence and exposure time on the outcome of the photodynamic anticancer activity of CoFe2O4-HPs-FAs in PC-3 cells to corroborate the importance of optimizing the irradiation parameters.
Authors : Dana Ben-Ayoun*, Yatir Sadia, Yaniv Gelbstein
Affiliations : Ben-Gurion University of the Negev, Beer-Sheva, Israel
Resume : One of the biggest obstacles in generating a working thermoelectric generator is turning materials into functional devices. Challenges that must be overcome include thermal stability at the material level and reliable contacts at the device level. In this research we extend from basic materials research, toward testing and improving some of the challenges to broad applications. Brazing compositions based on Ag-Cu-In were considered for bonding of thermoelectric material into Co bridges. Clear and fine interfaces without any noticeable formation of parasitic interaction layers were observed also following prolonged thermal treatment testing, highlighting the potential of such contacts while developing of practical PbTe based thermoelectric generators. The final goal of the research is achieving a generator prototype which will work in a lab testing facility.
Authors : Hwa Sub Oh1,*, Jong Min Park1, Sung Hoon Jung1, Dong Wook Lee2, Kang Seok Lee2
Affiliations : 1Korea Photonics Technology Institute, Korea 2LGS Incorporation, Korea
Resume : Recently, AlGaInP-based photonic devices have experienced an impressive evolution in both device performance and market volume. However, development of new applications is required in order to realize their full potential in areas such as use as a light source for auto focusing in digital cameras, special illumination for particular functions in agriculture, and in full color displays. To enlarge their utility in these applications, it is necessary to fabricate and understand a new structure capable of emitting longer wavelengths of around 700 nm. In particular, AlGaInP-based photonic devices are lattice-matched with respect to the GaAs substrate, which limits the emitting spectrum to around 650 nm at the longer peak wavelength side. To fabricate an photonic structure capable of emitting at a 700 nm peak wavelength, the composition (x) of GaxIn1-xP material in the active layer requires a compressive strain of larger than 1 %. This large lattice mismatch, however, causes significant problems in terms of both growth and device properties due to the formation of defects. To overcome these problems, it is necessary to relieve the well strain via the formation of islands, referred to as a Stranski-Krastanow (S-K) growth mode, in order to prevent the generation of dislocations [1,2]. However, in AlGaInP-based photonic devices emitting at a 700 nm peak wavelength, the effects of well strain on the epitaxial growth and the realization of device performance has yet to be extensively studied. In this study, we investigate the behaviors of morphological and optical characteristics on the composition of Ga0.33In0.67P material and demonstrate the performance of a device emitting at around 700 nm using quantum dot (QD)-based photonic devices.
Authors : Akshay Jain1, Jagriti Narang1*, Chaitali Singhal1, Manika khanuja2, Ashish Mathur1, C. S. Pundir3
Affiliations : 1Amity Institute of Nanotechnology, Amity University, Noida, 201301, (UP), India 2Centre for Nanoscience and Nanotechnology, Jamia Millia Islamia, New Delhi-110025, India 3Department of Biochemistry, Maharishi Dayanand University, Rohtak, 124001, Haryana, India
Resume : This paper reports an electrochemical microfluidic paper analytical device (EµPAD) for detection of recreational drug; metamphetamine (METH). METH is used as a recreational drug by youth and there is an urgent need to detect this drug as it is a potential neurotoxic agent. The EµPAD features a two-electrode system; counter and working electrode where the highly sensitive working electrode is decorated with zinc oxide nanorods (ZnONRs). The nano-size of the synthesized ZnONRs has been characterized by SEM, EDAX and XRD. The developed EµPAD represents many advantageous features of being simple, consistent, and low-cost. The limit of detection of METH is 1 µM with a linear range of 1 µM to 1 mM. The designed EµPAD can prove to be very effective in case of forensic diagnostic applications. This work provides a reliable diagnostic method for remote areas with limited resources, and will also help people who cannot afford expensive medical tests and have limited access to power and trained personnel.
Authors : Mariko Kobayashi(1)*, Yoshikazu Suzuki (2), Tomoyo Goto (3), Cho, Sung Hun (3), Tohru Sekino (3), Yusuke Asakura (4), Syu Yin (4)
Affiliations : *(1) Graduate School of Pure and Applied Sciences, University of Tsukuba, Ibaraki 305-8573, Japan. (2) Faculty of Pure and Applied Sciences, University of Tsukuba, Ibaraki 305-8573, Japan. (3) The Institute of Scientific and Industrial Research (ISIR-SANKEN), Osaka University, Osaka 567-0047, Japan. (4) Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Miyagi 980-8577, Japan.
Resume : Photocatalyst has been widely drawing attention as an environmental purification material for removing organic pollutant. From the pioneering study of Honda-Fujishima effect, the photocatalytic activity of titanium dioxide (TiO2) and other double oxides has been extensively investigated for last four decades. Among them, SrTiO3, a well-known double oxide, is an excellent photocatalyst due to its high photocorrosion resistibility and thermal stability. Also its perovskite-type structure enables cation doping to each site of ABO3. In order to obtain high photocatalytic activity, synthesis of nanoparticles which achieve both high crystallinity and specific surface area (SSA) is considered to be valid from recent study. Therefore, in this study, we synthesized SrTiO3 nanoparticles with high specific surface areas by hydrothermal method. This method enables synthesizing nanoparticles at lower temperature compared to conventional method, solid-state method. Titanium(IV) bis(ammonium lactato)dihydroxide solution (TALH) and strontium hydroxide octahydrate (Sr(OH)2·8H2O) were used as starting materials. SrTiO3 nanoparticles were directly synthesized by hydrothermal heating at 150ºC for 3-5 days. The crystal structure of obtained powders was analyzed by X-ray diffraction (XRD) and the micromorphology was observed by scanning electron microscope (SEM). Also the nitrogen adsorption/desorption isotherm was conducted and the SSA was determined by BET method.
Authors : Do Hyoung Kim, Hee Young Lee, Jai-Yeoul Lee
Affiliations : Dept. of Materials Engineering Yeungnam University, KOREA
Resume : Transparent p-n junction diodes have a wide range of applications in invisible optoelectronic devices such as smart window and organic lighting diodes. Although both of the n-type and p-type transparent conductive oxides (TCOs) are essential for transparent p-n junction diodes, the application of a transparent p-n junction is far from practical use due to the poor electrical conductivity and the optical transmittance of p-type materials. In this study p-type transparent semiconducting oxide films of ZnCo2O4, and ZnxCo3-xO4 thin films were deposited on glass and c-sapphire single crystal (000l) substrates by Pulsed Laser Deposition process. The effects of the type of the substrate, substrate temperature and atmosphere on the structural, electrical and optical properties of the ZnxCo3-xO4 thin films were examined. Although the crystallinity of the thin films was good, the preferred orientation of spinel thin films frequently observed in other spinel thin films such as of ZnCo2O4, was not observed in these films. The electrical conductivity of the ZnxCo3-xO4 thin films increased with the increasing Zn doping concentration. The electrical conductivity of the thin films on glass and sapphire substrates was improved by the introduction of oxygen and increased with increasing substrate temperature. The optical transmittance decreased with the introduction of oxygen gas and increased with increasing substrate temperature.
Authors : Inkyu Lee1, Dong Ryeol Whang2, Bong-Gi Kim3, Yejin An3
Affiliations : 1Department of Organic and Nano System Engineering, Konkuk University, Seoul, Korea; 2Linz Institute for Organic Solar Cells and Institute of Physical Chemistry, Johannes Kepler Universität Linze, Linz 4040, Austria; 3Department of Organic and Nano System Engineering, Konkuk University, Seoul, Korea
Resume : Efficient detection systems for volatile organic compound (VOC) have been demanded because of its harmful effect on human body. Several sensing systems have been developed to monitor the VOCs but critical limitations have been issued to be applicable for real-time detection, such as the necessity of complex equipment and in-situ signal amplification. Fluorometric chemosensor based on chemical reaction between target and emissive probe is a promising candidate because of both high sensitivity and selectivity. Herein, we designed a novel fluorometric chemosensor which can detect chloroform vapor. The invented sensing materials sharing triphenyl amine moiety lose their own emission upon excitation only under the existence of chloroform. To evaluate the selectivity and the sensitivity of the invented chloroform sensor (TPCA), we compared the response time of the invented fluorometric sensor on chloroform with other VOCs including similar structured chemicals with chloroform, and it was disclosed that the designed chemosensor selectively detect chloroform vapor with outstanding detection limit (below 500 ppm). In addition, it was revealed from electron paramagnetic resonance (EPR) spectroscopy that the detection of chloroform happened via excitation induced electron transfer from sensing material to chloroform molecule. After getting electron, chloroform decomposed and generated ·CHCl2 which caused an electrophilic substitution to sensing materials, resulting in emission quenching. The generation of CHCl2-adducted TPCA was characterized with LC-mass spectroscopy, and it was directly confirmed that the sensitivity of the designed TPCA on chloroform molecule is connected with the reaction capability of the electrophilic-type aromatic substitution of the generated dichloromethyl radical.
Authors : S. Taki, K. Moriuchi, A. Uruno, and M. Kobayashi
Affiliations : Dept. of Elec. Eng. & Biosci., Waseda Univ
Resume : Cu2ZnSnS4 (CZTS) is a material based on the earth abundant elements, and attractive material for the new photovoltaic absorber. Among various methods for preparing CZTS thin films, the evaporation and sputtering methods provide high crystallinity thin films. However, the segregation of residual elements and inclusion of by-products generally take place. The CZTS thin films could be also prepared using a spraying method of nanoparticle based ink. Nanoparticles of II-VI compounds and related materials have been successfully prepared by the ball milling method, and this method was applied to prepare nanoparticles of CZTS. The CZTS layer was prepared using this ink . The x-ray diffraction analysis was performed for the prepared thin film and the obtained data was similar to that of the starting material. After the film preparation, the selenization was performed using a Se vapor controlled annealing. By-product formation was surpressed by increasing the ramp up speed. When the film temperature was raised within 90 min (ramp up speed: 5 oC/min), the notable formation of CuxSe was confirmed at the surface of the CZTS layer. On the other hand, the formation of CuxSe was less clear when the temperature was raised within 15 min (ramp up speed: 30 oC/min). It was confirmed that the use of CZTS nanoparticle based ink and the Se vapor controlled annealing was an attractive method to fabricate large scale solar cells.
Authors : Younghyun Cho1, Hyunuk Kim1, and Shu Yang2*
Affiliations : 1Energy Efficiency and Materials Research Division, Korea Institute of Energy Research, Daejeon, 305-343, Korea 2Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, 19104, USA
Resume : Photonic crystals are dimensionally periodic dielectric structures exhibiting a photonic stopband that determine the wavelength of reflected light. The displayed color can be tuned by varying the particle size, lattice spacing, volume filling fraction and refractive index contrast within the porous network. Many have created polymeric inverse opals that can be responsive to external stimuli to change colors. However, few can record the mechanical force in real-time or the recorded force is rather small. Here, we created inverse opals as mechanochromic patches by backfilling the colloidal crystals of silica particles (diameter of 320, 285, and 238 nm) with thermoplastic photoresist, SU-8, followed by removal of the templates. Due to elastoplastic deformation of SU-8 films, the deformed inverse opals do not fully recover, allowing us to establish the relationship between the mechanical force and optical responses. When the normal forces of 30, 60, and 90 mN are applied to the pristine inverse opal (320 nm), the stopband blue-shifts to 570, 500, and 440 nm, respectively. To reveal the underlying deformation mechanisms as well as the overall mechanical responses of the inverse opal of SU-8 under different loads, we carry out micromechanical modeling using the finite element method (FEM). The simulation results corroborate well with experiments, suggesting that the uniform variation in pore geometry under the compression play a key role in determining mechanochromic property. The inverse opals prepared from SU-8 can be potentially used as power-free mechanochmic sensors to measure the magnitude of shockwaves without the need of complicated instrumentation for in-situ imaging.
Authors : Su Yeon Lee, Eun Jung Lee, Beyong-Hwan Ryu, Sunho Jeong, Youngmin Choi
Affiliations : Korea Research Institute of Chemical Technology (KRICT)
Resume : Energy harvesting that can scavenge various kinds of mechanical energy from several different sources have attracted great attention. Since irregular mechanical energy sources can be accessible than other outdoor renewable energy resources, energy harvesters based on mechanical and vibrational energy sources from human activities such as pressure, bending, stretching motions have been developed recently. In particular, a flexible energy-harvesting device consisting of piezoelectric materials has been studied as a power source for flexible and wearable electronic devices because the piezoelectric materials can effectively convert to electrical energy from mechanical energy. Recently, many researchers have attempted to achieve highly efficient energy-harvesting devices using several fabrication methods such as dense nanowire growth, electrospinning, and transfer techniques with various piezoelectric materials. The flexible nanocomposite generator using piezoelectric ceramic nanoparticles, nanotubes, and nanostructures offers a novel and facile fabrication approach for low-cost self-powered energy devices. However, there are still the challenge problems with flexible piezoelectric nanogenerators in terms of low dispersibility of ceramic nanoparticles, insufficient output performance, and poor mechanical robustness. Here we report the flexible nanocomposite generator (NCG) based on piezoelectric nanoparticles and polymer. The piezoelectric PZT particles with inherently excellent properties was used to disperse in polymer matrix for production of a high-performance NCG device. The NCG was attached to metal-coated plastic substrates. Under periodic external mechanical deformation by bending stage, electric signals are repeatedly generated from the NCG device. The NCG exhibited high power generation, high mechanical durability, and excellent robustness.
Authors : Takahiro Furuki, Masashi Ota, Yuya Ishii, Mitsuo Fukuda
Affiliations : Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology
Resume : High-speed information processing circuits can be produced using surface plasmon polaritons (SPPs) as signal carriers. Short-range SPPs (SRSPPs) enable optical signals to be confined on the nano-scale, further, their group velocities can be decreased by decreasing the width of the waveguides used. In this paper, we present a feasible plasmonic time delay and switching structure using SRSPPs on a bow-tied metallic waveguide that can be fabricated using a CMOS-compatible process. The structure comprises a Au bow-tied waveguide with a taper angle of 10° and a taper length of 5000 nm. Here, Au was chosen instead of Al owing to its superior chemical stability. SPP signals were inputted into the structure; using the finite-different time-domain method the delay time was thus numerically estimated to be 60.7 fs. This is a longer delay than when using a ridged Au waveguide (21.9 fs). Next, switching of the SRSPP intensity on the bow-tied Au waveguide was demonstrated both numerically and experimentally by adjusting the phase difference between input and control signals. A 500-nm-thich Au film was deposited on a quartz substrate and patterned using focused ion beam etching. The extinction ratio of the coordinate and anti-phase SPP inputs was measured at the output using a scanning near-field optical microscope system; the ratio was 10.4 dB. These results confirm the feasibility of our proposed plasmonic time delay and switching structure using SRSPPs on a bow-tied metallic waveguide.
Authors : Dae Seon Kwon, Cheol Hyun An, Sang Hyeon Kim, Hoju Song, Seong Tak Cho, Soon Hyung Cha and Cheol Seong Hwang*
Affiliations : Dae Seon Kwon, Cheol Hyun An, Sang Hyeon Kim, Hoju Song, Seong Tak Cho, Soon Hyung Cha ; Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, Korea Cheol Seong Hwang ; Department of Materials Science and Engineering and Inter-university Semiconductor Research Center, Seoul National University, Seoul 151-744, Korea.
Resume : Ru attracts much attention as a potential electrode of the next-generation dynamic random access memory (DRAM) capacitor due to its promising properties such as low resistivity (~7 μΩ·cm) and high work function (~4.7 eV). Atomic layer deposition (ALD) is the most suitable method among the many thin film growth techniques to grow uniform and conformal film over three-dimensional structures. Upon Ru deposition by ALD, selecting appropriate Ru precursor is crucial, because the film growth characteristics and its properties are highly affected by the Ru precursor used. Currently, metal-organic precursors like Ru(EtCp)2 and DER (Ru(EtCp)(η5-CH2C(Me)CHC(Me)CH2)) are widely used, but problems such as long incubation time and low growth rate still exist. Therefore, it is necessary to develop Ru precursor with improved performance. A new precursor, Rudense (Ru(EtCp)(η5-CH2C(Me)CHC(Me)O)) (TOSOH Co.), was developed, which was adopted to grow Ru film via an ALD method. In this study, the ALD behavior of Ru thin films is reported, using Rudense and O2 as a Ru precursor and a reactant, respectively, at temperatures ranging from 250 to 270 ℃. At 250 ℃, the self-limiting growth was confirmed by controlling the Ru precursor and O2 feeding time. A saturated growth rate of 0.09 nm/cycle and very low incubation cycles (<20) were obtained, which are highly improved results compared with the results from DER. Also, well crystallized Ru phases and a low resistivity were observed from an extremely thin films (< 3nm). Chemical and structural analysis, such as X-ray photoelectron spectroscopy and atomic force microscopy measurements, were conducted to examine the deposited films in more detailed manner. Finally, the step coverage was also evaluated.
Authors : Jun Cao, Haixue Yan
Affiliations : Queen Mary university of London
Resume : The control of polarization states in ferroelectrics is the underlying basis of using two spontaneous polarisation ?up? and ?down? to record the binary code ?0? and ?1? which was firstly proposed by J.R. Anderson who worked in Bell labs at 1952. Ferroelectric RAM is a random-access memory similar in construction to DRAM but uses a ferroelectric layer instead of a dielectric layer to achieve non-volatility. FRAM is one of a growing number of alternative non-volatile random-access memory technologies that offer the same functionality as flash memory. FRAM advantages over flash include: lower power usage, faster write performance and a much greater maximum number of write-erase cycles (exceeding 1016 for 3.3 V devices). Disadvantages of FRAM are much lower storage densities than flash devices, storage capacity limitations, and higher cost . Multiferroic materials exhibit spontaneous ferroelectric, ferroelastic and ferromagnetic order simultaneously and these coexisting ferroic orders can couple in the same phase. These characters makes multiferroics has 4 theoretical logical memory states, 4 logic state possess more storage capacity than traditional memory (2 logical state in traditional memory). If the memory recording mechanism is binary system (1024kb=1mb), the memory capacity could up to 2^10 times exceed the traditional memory device. In addition, it also possesses the advantages of FRAM (fast writing and reading performance, low power usage etc.). Beyond that, multifrerroics could also be applied to the high sensitive sensors and optical filters, thus, multiferroics have been one of the hot research topics . The most difficult condition that scientists encountering is that there are few single phase multiferroic in nature since the ferroelectricity and magnetism tend to exclude each other . Nicola A. H. found that the transition metal d electrons which are necessary for magnetism reduce the tendency for off-center ferroelectric distortion. Many efforts have been devoted for new room temperature magnetoelectric multiferroics due to a strong desire to fabricate novel function. Two characters are necessary to satisfy the commercial device: room temperature multiferroic behavior and strong coupling between ferroelectric and magnetic properties. BiFeO3(BF) is one of the most promising materials for technological applications, being characterized by high ferroelectric (FE) Curie temperature (TC-1103K) and antiferromagnetic (AFM) Néel temperature (TN-643K). However, the high leakage current, tendency to fatigue and secondary phase in the grain boundary restrict its application, and BiFeO3 is antiferromagnetic under room temperature, thus, BNT and BT are added as components. BNT is chosen to form a solid solution with BF, because it is one of lead-free perovskite ferroelectric materials with FE Curie temperature TCE-593K and possesses rhombohedral symmetry with space group R3c similar to that of BF.
Authors : Guilherme Fabris, Ricardo Paupitz
Affiliations : Departamento de Fisica, IGCE, Sao Paulo State University, 13506-900, Rio Claro, SP, Brazil
Resume : A class of two dimensional structures based on the architecture of the so called "octa-graphene" is theoretically investigated. The building blocks used to construct these structures are butadienes and linear carbon chains, with single and triple bonds alternation. Our calculations were carried using density functional theory - based methods and include the calculation of electronic and structural properties of these nanostructured materials including also some of their elastic properties, like Young modulus and Poisson ratio. Our calculations predict that these structures can be stable at room temperature and that their behavior goes from metallic to semiconductor, depending on the specific building blocks. The atomization energies (relative to graphene) are predicted to be in a range similar to that found for other two-dimensional materials, like graphenylene. Due to their high porosity and special mechanical properties, these structures may be good candidates for gas separation membranes or to the construction of nanodevices in the near future.
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Plasmonics_2 : Jost Adam, Yogendra Mishra
Authors : Paola Pellacani, Lucia Fornasari, Chloe Rodriguez, Vicente Torres-Costa, Franco Marabelli, Miguel Manso-Silvan
Affiliations : Departamento de Física Aplicada, Universidad Autonoma de Madrid, 28049 Madrid, Spain; Universitá degli Studi di Pavia, Dipartimento di Fisica, 27100 Pavia, Italy
Resume : Hybrid photonic-plasmonic systems are promising devices in fields such as biosensing and optoelectronics, due to their specific modulation of light behaviour. In this work, multilayer porous silicon (PSi) interference structures have been used as support for arrays of Au nanocavities to combine the photonic properties of the former with the plasmonic properties of the latter, to develop an hybrid photonic-plasmonic device. PSi multilayer stacks were produced by carefully tuning the electrochemical etch of p-type monocrystalline silicon wafers to produce contrasting porosity strata and thus achieve a predetermined interference response . On top of this structure, a large area colloidal monolayer was deposited and shaped by reactive ion etching, A 200 nm thick Au layer was deposited followed by a final step of lift off of the remaining colloidal structure, producing a plasmonic Au nanocavity array . Different post-processing treatments of annealing and chemical etching were applied to tailor the Au microstructure. These hybrid structures have been characterized by scanning electron microscopy, which has allowed to infer the main characteristics of the system, such as thickness of individual PSi layers in the interference stack, and the evolution of the grain size of the Au out-structure. In addition, cummulative reflectance measurements at each fabrication step allowed evaluating the individualized optical contribution of each structure and their coupling. Results suggest that these type of hybrid structures may allow the development of dual photonic-plasmonic biosensors with enhanced sensitivity.  C. Pacholski. Photonic Crystal Sensors Based on Porous Silicon. Sensors 2013, 13, 4694-4713.  B. Bottazzi, et al. Multiplexed label-free optical biosensor for medical diagnostics. Journal of Biomedical Optics 2014, 19 (1), 017006.
Authors : Christos Tserkezis, N. Asger Mortensen
Affiliations : Center for Nano Optics, University of Southern Denmark
Resume : Plasmonics provides excellent templates for engineering emission from organic molecules, fluorescent dyes and quantum dots, as it is characterised by strong enhancement and confinement of light and large modification of the local density of states. Modern nanotechnology offers unprecedented flexibility in designing narrow plasmonic cavities, and precisely positioning emitters in them, with few- or even sub-nm accuracy. Such experimental advances go hand in hand with novel theoretical approaches which highlight the necessity to depart from classical electrodynamics. Nonclassical effects such as electron spill-out, quantum tunnelling, nonlocal screening, and surface-enhanced Landau damping become highly relevant in these situations. Here we implement the Generalised Nonlocal Optical Response theory to explore how the latter two, larger-scale effects, affect the coupling of emitters with canonical plasmonic nanostructures. For single fluorescent molecules coupled to the plasmon modes of Ag nanoshells, the nonlocal description shows that fluorescence enhancement reduces by up to two orders of magnitude. On the other hand, nonlocality becomes less important when examining the Rabi splitting induced by the interaction of the excitonic and plasmonic states in J-aggregates/Ag nanoparticle systems. Our discussion provides useful insight into experimentally relevant nonclassical processes, and should therefore facilitate the analysis of emitter-plasmon hybrids in practice.
Authors : Jae Yong Park, and Jong-Lam Lee
Affiliations : Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang, Korea
Resume : Implementing nanostructures on flexible plastic film is indispensable for highly efficient optoelectronic devices. Recently, several attempts to realize nanostructures on flexible polymer substrates have been developed through nanoimprint and Langmuir-Blodgett method. However, there are distinct limitations like as low throughput, deformation, complex process and long synthesis time, in application to highly efficient flexible optoelectronic devices. Here, we will propose a new and simple growth of nanorod on polymer film by plasma-assisted strain relaxation to overcome the existing problems. By employing the Cl2 plasma treatment onto the Ag film on polymer substrate, large lattice mismatch between Ag and AgCl caused the substrate to flex. This flexion provided effective strain relaxation and access of Cl radicals to the surface of the growing AgCl nanorods (NRs). From the crystallographic analysis by transmission electron microscopy and X-ray diffraction, we elucidated the single crystal AgCl NR with (200)-preferred direction and proved that quasi-epitaxial growth is made by matching domains. The nanorods grown for 45 s exhibit superior haze up to 100 % and luminance of optical device increased by up to 33%. The advantages of this technique are low temperature process and high growth rate (about 2,000 nm min-1). Such process condition allows the AgCl NRs to implement the R2R process.
Authors : Khinevich Nadia, Kseniya Girel, Hanna Bandarenka
Affiliations : Belarusian State University of Informatics and Radioelectronics, Minsk, Belarus.
Resume : In this work we have reported on hybrid metallic nanostructures that surface plasmon resonance is modulated by combination of silver nanoparticles with copper or nickel nanovoids. Such hybrid materials were fabricated by electroplating and following silver immersion deposition on macroporous silicon. Porous material played a role of template for the formation of nanovoids. Presented data implies that morphology and ratio of the silver/copper, silver/nickel nanostructures on macroporous silicon allow to manage the position of their surface plasmon resonance band from near UV to IR ranges. It is shown that such nanostructures demonstrate efficiency in surface enhanced Raman scattering both under blue and red excitation wavelengths and allow detection of test organic molecules which concentration varies from micro- to nanomol.
Authors : Nimshi. L. Fernando(1), Nilwala. Kottegoda(2), J. K. D. S. Jayanetti(1), Veranja Karunaratne(3), Dilushan. R. Jayasundara(1)
Affiliations : (1)Department of Physics, University of Colombo, Sri Lanka; (2)Department of Chemistry, University of Sri Jayewardenepura, Sri Lanka; (3)Department of Chemistry, University of Peradeniya, Sri Lanka;
Resume : In recent times the design and development of bio sensors with functional coatings have increasingly become popular. One such type of coating is Hydroxyapatite. In most cases the Hydroxyapatite-based coatings are fabricated with deposition of thin films via magnetron sputtering, electrophoretic deposition and spin coating techniques with subsequent high temperature sintering. The high temperature treatment greatly limits the choice of materials that can be used in the sensor fabrication and also will not be economically viable. Recently there were studies that have utilized Hydroxyapatite thin films deposited under ambient conditions for sensing adsorption desorption behaviours of proteins. In this research the fabrication of Nano-Hydroxyapatite films on quartz crystal microbalance sensors using electrophoretic deposition and spin coating technique are reported. Synthesized Nano-Hydroxyapatite particles were characterized by X-ray powder diffraction and scanning electron microscope. The study looks at the stability of the Nano-Hydroxyapatite films immediately after deposition, after sonication and after prolong water exposure. The stability is measured by monitoring the changes in the quartz crystal microbalance resonance frequency, which is proportional to the mass accumulation or removal, at each of the above steps. Separate scanning electron microscope measurements were carried out to confirm the observations. The results from the above experiments show that the initial thicknesses of the Nano-Hydroxyapatite films formed are concentration dependent with thicker coating obtained with the electrophoretic deposition method compared to that obtained with spin coating. However, these thicker coatings are unstable and can easily be reduced to thin quasi stable Nano-Hydroxyapatite films on the gold surfaces. While the resulting thin films show significant stability under ultrasonic treatment in aqueous medium, the subsequent prolong exposure to similar mediums show the complete removal of the Nano-Hydroxyapatite film from the substrate. This instability can be related to the preferential crystal orientation of the Nano-Hydroxyapatite particles on the gold surface. Comparative studies on coatings fabricated from other forms of Hydroxyapatite structures indicate that the resulting film morphology and the interfacial properties are the key parameters that controls the thin film stability. Keywords: Nano-Hydroxyapatite, Quartz crystal microbalance, Thin films Financial assistance given by the National Research Council Sri Lanka (NRC Grant: 15 004) is acknowledged
Authors : Thumu Udayabhaskararao,1 Thomas Altantzis,2 Lothar Houben,3,4,5 Marc Coronado-Puchau,6 Judith Langer,6 Ronit Popovitz-Biro,3 Luis M. Liz-Marzán,6,7 Lela Vuković,8 Petr Král,9,10,11 Sara Bals,2 Rafal Klajn1*
Affiliations : 1Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel; 2 EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium; 3 Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel; 4 Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, 52425 Jülich, Germany; 5 Peter Grünberg Institut, Forschungszentrum Jülich, 52425 Jülich, Germany; 6 CIC biomaGUNE, Paseo de Miramón 182, 20014 Donostia-San Sebastián, Spain; 7 Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain; 8 Department of Chemistry, University of Texas at El Paso, El Paso, TX 79968, USA; 9 Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA; 10 Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA;11 Department of Biopharmaceutical Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
Resume : Ordered arrays or superlattices consisting of nanocrystals (NCs) of different diameter represent an important class of materials. There have been advanced methods to assemble nanoparticles of two different materials into binary nanoparticle superlattices (BNSLs).1 Recently, Rafal et al. has reported highly organized monocomponent helical structures formed from magnetic cubes.2 But this process is limited only to magnetic inorganic materials. On the other hand, there were no unique approaches to make highly organized non-close packed self-assembled structures in the size regime below 20 nm. For example, self-assembly of alkanethiol-protected gold nanoparticles can only give rise to close-packed structures such as hexagonal or FCC arrangements. It is challenging to produce superlattices of inorganic nanoparticles into loosely packed arrangements. Despite these advances in template-assisted arrangement of inorganic nanoparticles,3 little progress has been made over controlling the desired structure of the superlattices. Here, we developed a new approach based on post-modification of BNSLs to create unprecedented monocomponent nanoparticle crystals. We demonstrate the formation various non-close packed monocomponent structures. We have examined several different NP arrays as substrates for surface-enhanced Raman scattering (SERS) and found the best arrays for superior signal enhancement properties. 1. A. Dong, J. Chen, P. M. Vora, J. M. Kikkawa C. B. Murray Nature 2010, 466, 474. 2. G. Singh, H. Chan, A. Baskin, E. Gelman, N. Repnin, P. Král, R. Klajn Science 2014, 345, 1149. 3. S. Y. Park, A. K. R. Lytton-Jean, B. Lee, S. Weigand, G. C. Schatz, C. A. Mirkin, Nature 2008, 451, 553.
Authors : S.M.B. Albahrani1,2, S. Ayrinhac1, P. Colomban2, I. Lisiecki2, S. Costanzo2, M. Gauthier1, F. Decremps1, G. Simon1
Affiliations : 1 Sorbonne Universités, UPMC Université Paris 06, CNRS, UMR 7590 IMPMC, F-75005 Paris, France 2 Sorbonne Universités, UPMC Université Paris 06, CNRS, UMR 8233 MONARIS, F-75005 Paris, France
Resume : Magnetic metallic nanoparticles (NPs) are self-assembled, under specific conditions, in organized structures, called supracrystals . Such self-organization process requires a small particle size dispersion as well as the use of an adapted coating agent preventing coalescence and oxidation. Supracrystals potential covers various fields, including electronics, charge transport and information storage. However, their thermodynamic properties have been little examined, particularly under high pressure conditions. The current work aims at establishing the temperature-pressure phase diagram of Cobalt-based supracrystals hold together via lauric acid chains. To this end, two experimental techniques were employed in combination with a resistive heated membrane diamond anvil cell (mDAC) for the generation of high pressures (0-20 GPa) and moderate temperatures (0-200 °C) conditions. First, low wavenumber Raman scattering was used to determine both spherical and quadrupole vibrational modes of individual Co NPs . In addition, the collective vibrations of the supracrystal, and their dependence on temperature/pressure conditions, were detected with a pump-probe picosecond acoustics setup . Lauric acid was studied separately in order to identify its contribution to the physical properties of the supracrystals.  I. Lisiecki et al., Adv. Mater. 15, 712 (2003).  G. Simon et al., J. Raman Spectrosc, 47, 248 (2015). F. Decremps et al., Ultrasonics, 56, 129 (2015).
Authors : Mina Mirsafaei1, Paola Pellacani2, Paweł Piotr Cielecki1, Miguel Manso Silván2, Horst-Günter Rubahn1, Jacek Fiutowski1, Jost Adam1 and Morten Madsen1
Affiliations : 1SDU NanoSYD, Mads Clausen Institute, University of Southern Denmark, Alsion 2, Sønderborg, DK-6400, Denmark 2 Departamento de Física Aplicada e Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, Facultad de Ciencias M12, 28049 Madrid, Spain
Resume : To date, studies of noble metal nanostructures and their use as biosensors, optical filters, plasmonic waveguides and in photovoltaic technology have attracted significant attention. The plasmonic properties of the metallic nanostructures can be tailored by varying different parameters such as size, shape, surface structure and particle spacing.1 In this work, we theoretically and experimentally investigate the plasmonic properties of periodic gold nano-triangle arrays. We fabricate large-area periodic gold nano-triangle arrays on glass substrates using a nano-sphere lithography method. The nano-sphere lithography technique is based on the self-assembly of polystyrene nano-spheres achieving a well-packed hexagonal mask, which leads to the formation of metal triangle nanostructures after metal deposition and mask removal. The field enhancement properties, induced by the triangularly shaped nanostructures arranged in hexagonal arrays, are characterized by a laser ablation technique.2 To better understand the optical behavior of this nanostructure, we perform numerical studies, based on finite-difference time-domain (FDTD) analysis and finite element method (FEM), modeling the electromagnetic field distribution of the targeted substrate. We study the field distribution as a function of input light polarization and nanostructure geometry. Our results indicate that the nanostructure-induced plasmonic properties alter by varying these parameters. In addition, our study provides important information for nanostructure design towards high electric field enhancement in thin film devices. Together with the prospect of low production cost and the ease of scalability, we believe that the presented nanostructures hold prospect to be beneficial for the optical enhancement in various optical and optoelectronic devices. 1. Hulteen, J. C. et al. Nanosphere Lithography: Size-Tunable Silver Nanoparticle and Surface Cluster Arrays. The Journal of Physical Chemistry B 103, 3854-3863 (1999). 2. Fiutowski, J., Maibohm, C., Kjelstrup-Hansen, J. & Rubahn, H.-G. Laser ablation of polymer coatings allows for electromagnetic field enhancement mapping around nanostructures. Applied Physics Letters 98, 193117 (2011).
Graphene : Yogendra Mishra
Authors : C.A. Chavarin , C. Strobel , J. Kitzmann , G. Lupina , M. Albert , J. W. Bartha , C. Wenger 
Affiliations :  IHP, Im Technologiepark 25, Frankfurt an der Oder, Germany  TU Dresden, Noethnitzer str. 64, Dresden, Germany
Resume : Graphene has been proposed as the current controlling element of vertical transport in heterojunction transistors due to its high mobility and 2D nature. Simulations of graphene acting as a thermionic barrier between the transport of two semiconductor layers have shown cut-off frequencies larger than 1 THz. Furthermore, along with graphene the use of doped amorphous silicon (a-Si:H) as the semiconductor for this approach could enable flexible electronics with high cutoff frequencies. In this work, we will present the fabrication of a vertical structure where graphene is embedded between two differently doped a-Si:H layers deposited by very high frequency (> 100 MHz) plasma-enhanced chemical vapor deposition on a rigid substrate. The operation of this vertical transistor is investigated by the two diode-like interfaces by means of temperature dependent current-voltage (IV) and capacitance-voltage (CV) characterization. It will be shown that the vertical current between the a-Si:H layers is successfully controlled by the ultra-thin graphene base voltage. While current saturation is yet to be achieved, high current gain values were obtained. These results show promising advances for the application of graphene base heterojunction transistors.
Authors : Marine Caux, John T.S. Irvine, Hicham Idriss
Affiliations : School of Chemistry, University of St Andrews, North Haugh, St Andrews, United Kingdom; School of Chemistry, University of St Andrews, North Haugh, St Andrews, United Kingdom; SABIC-Corporate Research and Development (CRD), KAUST, Thuwal 23955, Saudi Arabia
Resume : Charge recombination rate is at the essence of photocatalysis. Introducing a metal, is a common approach to decrease the energy loss through electron-hole recombination via electron transfer from the conduction band of the semiconductor to the metal . Gold nanoparticles (Au NPs) have proven to be effective through both Mott-Schottky junction, and localized surface plasmon resonance (LSPR) properties ; these can be tuned by altering their shape and size . Tailoring Au NPs size and morphology has been widely studied due to the benefits of LSPR in multiple fields . Achieving a similar degree of morphology control of Au NPs deposited on a support would be extremely useful to the photocatalysis field. In this work, we show that non-spherical Au NPs could be directly grown on a visible light harvesting semiconductor: graphitic carbon nitride (Eg=2.7eV) . A deposition precipitation method was used in presence of urea, a process used for spherical Au NPs deposition on TiO2 [6,7] and g-C3N4 . However, our work demonstrates the preparation steps necessary to reduce the gold precursor to Au0 is of high relevance with regards to Au NPs shape. A mixture of various morphologies (nanorods, cubes, triangular nanoplates or tetrahedral) was obtained under reducing conditions. While work is in progress to understand the effect of reduction conditions on the Au NPs shape on g-C3N4, an increase in the reaction rate by 1.6-fold for the photocatalytic hydrogen evolution from oxalic acid, when compared to regular spherical Au NPs, was seen on these irregular shaped Au NPs. This increase might be linked to the enhancement of the electric field at the edges and corners of Au NPs  which in turn is poised to decrease the electron-hole recombination rate of the semiconductor.  V. Subramanian, E. Wolf, P. V. Kamat, J. Phys. Chem. B. 105 (2001) 11439–11446.  M.A. Khan, L. Sinatra, M. Oufi, O.M. Bakr, H. Idriss, Catal. Letters. 147 (2017) 811–820.  X. Zhang, Y.L. Chen, R.-S. Liu, D.P. Tsai, Rep. Prog. Phys. 76 (2013) 46401.  M.R. Langille, M.L. Personick, J. Zhang, C.A. Mirkin, J. Am. Chem. Soc. 134 (2012) 14542–14554.  K. Domen, X. Wang, K. Maeda, A. Thomas, K. Takanabe, G. Xin, J.M. Carlsson, M. Antonietti, Nat. Mater. 8 (2009) 76–80.  Z.H.N. Al-Azri, W.T. Chen, A. Chan, V. Jovic, T. Ina, H. Idriss, G.I.N. Waterhouse, J. Catal. 329 (2015) 355–367.  A. Hugon, L. Delannoy, C. Louis, Gold Bull. 41 (2008) 127–138.  S. Samanta, S. Martha, K. Parida, ChemCatChem. 6 (2014) 1453–1462.  S. Link, M.A. El-Sayed, Int. Rev. Phys. Chem., 19 (2000) 409–453.
Authors : Pulak Chandra Debnath, Siam Uddin, Yong-Won Song
Affiliations : Center for Opto-Electronic Materials and Devices, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Nanomaterials Science and Engineering, Korea University of Science and Technology, Daejeon 34113, Republic of Korea
Resume : Graphene, with its high optical nonlinearity and dispersionless nonlinear optical response over a broad wavelength range, has been investigated widely to implement optical devices such as fiber laser, broadband optical modulator, polarizer, and optical switches. Conventionally synthesized graphene relying on high temperature and vacuum equipment mostly requires deleterious transfer steps to implement devices that degrade the graphene crystal quality, thereby affecting the efficiency of nonlinear optical operation and lacking the customized patterning with minimized footprint as well as missing the facilitated fabrication process. Here, we present a laser induced in situ synthesis of multilayered graphene directly onto the optical fiber in ambient condition for absolute investigation of as-grown graphene crystal in optical domain. The evanescent field of an amplified continuous wave (CW) laser, propagating through the waveguide, provides activation energy for carbon atoms to diffuse through the nickel catalyst and to grow graphene directly on the waveguide. The in situ grown graphene shows nonlinear optical absorption property with the modulation depth of 3 % and acts as saturable absorber (SA) in the fiber laser ring cavity to generate ultrafast optical pulses, thus ensuring the passive mode-locking of fiber laser operating in femtosecond scale. We also demonstrate ultrafast all-optical switching near 1550 nm by capitalizing four-wave mixing (FWM) with the grown graphene to ensure that the nonlinear response enhancement of 66 % is originated from the graphene. The input signal channel is modulated at the ultrafast speed up to 20 GHz, and this modulation information is successfully copied to the newly generated signals.
Authors : Teresa Cusati, Alessandro Fortunelli, Giuseppe Iannaccone
Affiliations : Dipartimento di Ingegneria dell’Informazione, Universita di Pisa, Via G. Caruso 16, 56122 Pisa, Italy; CNR-ICCOM, Istituto di Chimica dei Composti Organometallici, Via G. Moruzzi 1, 56124, Pisa, Italy; Dipartimento di Ingegneria dell’Informazione, Universita di Pisa, Via G. Caruso 16, 56122 Pisa, Italy;
Resume : The fabrication of metal/graphene contacts is one of the main technological issues in the development of graphene-based electron devices, whose performance strongly depends on the capability to achieve very low contact resistance. Gold contacts seem to be particularly promising from the experimental point of view, but few theoretical studies are available. Here we investigate the properties of two types of gold/graphene contacts: flat contacts – between vertically stacked layers of gold and graphene – and edges contacts – between the edges of a graphene layer and gold. We perform ab-initio simulations of electron properties based on Density Functional Theory (DFT) and quantum simulations of electron transport through the interface using the PWCOND module of Quantum Espresso. We show that the nature of the bonds formed in the case of different contact configurations has a strong effect on contact resistance and the formation of strong chemical bonds in the case of edge contacts leads to lower contact resistance.
Authors : Mikołaj J. Sadek, Jacek A. Majewski
Affiliations : Institute of Theoretical Physics, Faculty of Physics, University of Warsaw Pasteura 5, 02-093 Warsaw, Poland
Resume : Two-dimensional layered materials remain in focus of researchers, and recently heterostructructes of these materials have attracted a lot of attention. Graphene and hexagonal Boron Nitride (Graphene/h-BN) heterostructures constitute an important family of such materials. Consisting of layers of graphene and BN sheets with various stacking, vertical Graphene/h-BN heterostructures combine properties of both materials. Many different possible arrangements of heterostructures’ building blocks allow for design materials with desired properties and functionalities, for which the quantitative predictions of relation between morphology of the structures and their electronic structure play the crucial role. We present an in-depth theoretical study of graphene/h-BN heterostructures carried out in the framework of density functional theory. We focus on the relation between electronic and structural properties, and investigate the role of van der Waals interactions in these systems, using DFT-D2 scheme proposed by Grimme. The results of our investigations shed light on physical mechanisms that determine the magnitude of the energy band gap and provide a tool for band gap engineering in graphene/h-BN systems. Results of present studies for Graphene/h-BN heterostructures have been compared to other theoretical works and available experimental data.
Authors : Mahsa Jalali, Zhengtang Luo
Affiliations : Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
Resume : Monolayer molybdenum disulphide (MoS2) is a promising candidate in optoelectronics due to its strongly-bond excitons and their non-linear optic behaviour. However, the low refractive index characteristic of this two dimensional (2D) material results in poor light-matter interactions. We demonstrate a strategy to enhance photoemission of CVD-grown MoS2 for more than 20-fold by embedding designed silver nanostructures in the monolayer structure. This is achieved by fabrication of silver nanodisc arrays able to generate localized surface plasmon resonance (LSPR) collective modes, with addition modification as dimer and trimer with 30 nm gap and 400 nm pitch to maximize light- matter interaction. The dimers and trimers were embedded using O2 reactive ion etching (RIE) assisted with a designed mask. This designed arrays led to prevailing exciton over trion recombination, which enhance photoemission of monolayer MoS2. In summary, RIE defect engineering of MoS2 in order to make nanohole arrays along with coupling modified LSPR supported silver nanostructures leads to enhancing light-matter interaction and consequently increment in photoluminescence of MoS2. This project is supported by the Research Grant Council of Hong Kong SAR (Project Number 16204815), the Innovation and Technology Commission (ITS/267/15). We appreciate support from Center for 1D/2D Quantum Materials, financial support from the Guangzhou Science & Technology Project (2016201604030023).
Authors : Noemí Antón-Millán, Javier García-Tojal, Santiago Cuesta-López, Juan Antonio Tamayo-Ramos
Affiliations : Noemí Antón-Millán; Santiago Cuesta-López; Juan Antonio Tamayo-Ramos: International Research Centre in Critical Raw Materials-ICCRAM, University of Burgos, Plaza Misael Banuelos s/n, 09001 Burgos, Spain Noemí Antón-Millán; Santiago Cuesta-López; Juan Antonio Tamayo-Ramos: Advanced Materials, Nuclear Technology and Applied Bio/Nanotechnology. Consolidated Research Unit UIC-154, University of Burgos, Hospital del Rey s/n, 09001 Burgos, Spain. Javier García-Tojal: Department of Chemistry, University of Burgos, Plaza Misael Bañuelos s/n., 09001 Burgos, Spain
Resume : Biomolecule-graphene composites continue to gain attention for their use in biomedical and biotechnological applications, such as: next generation biocatalysis, biosensors, implantable electronic devices, or drug delivery. In this study, three commercial graphene derivatives: graphene oxide (GO), graphene oxide nanocoloids (GOC), and polycarboxylate functionalized graphene nanoplatelets (GN), were compared as biomolecule carriers. ATR-FTIR analysis showed that GO and GOC were similar in functional groups content, and very different to GN. The α-L-Rhamnosidase RhaB1 from the bacterium Lactobacillus plantarum, a relevant enzyme in the pharma and food industries, was immobilized on the materials. RhaB1-GO and RhaB1-GOC showed a high binding efficiency, while the enzyme loading on GN was low. Regarding the biochemical properties of RhaB1-GO, RhaB1-GOC, and RhaB1-GN, the thermal stability and the effect of pH on the activity of all immobilized enzymes was similar to that observed for the free enzyme. Also, the Km for the immobilized and soluble enzymes was the same. However, the activity-temperature profiles and the response to different inhibitors varied significantly between them. Finally, the free RhaB1 and the immobilized enzyme in GOC showed the highest stability degree, keeping almost the 100% their initial activity at least after 8 weeks of storage at 4 °C. This study shows that distinct graphene derivatives can influence differently on an enzyme catalytic properties.
Authors : Vijay K. Tomer, Ritu Malik, Lorenz Kienle
Affiliations : Synthesis and Real Structure Group, Institute of Materials Science, Kiel University, Kaiserstr. 2, D-24143, Kiel, Germany
Resume : Need for fabrication of low temperature gas sensors has fostered extensive research in realizing 2D materials with high surface area for fast response and low ppm detection of volatile organic compounds (VOCs) [1-2]. In this work, a fast response and low ppm acetone gas sensor operating at near room temperature has been fabricated successfully by utilizing cubic mesoporous g-CN (commonly known as g-C3N4), synthesized through template inversion of mesoporous silica, KIT-6 [2-3]. Upon exposure to 20 ppm acetone at 200 C, the optimized In(III)-SnO2/g-CN showed significant higher response (Ra/Rg = 18.2), fast response (14 s), and full recovery within 4 s in air. The sensor was also able to detect 20 ppm (R=1.7) and 50 ppm (R=3.9) acetone gas at 80 C. Compared to mesoporous In(III)-SnO2, the g-CN supported In(III)-SnO2 nanocomposite shows 2.8 fold increase in response to acetone gas while reducing the operating temperature by 50 C. This outstanding response is due to easily accessible 3D mesoporous structure with higher surface area and their unique planar morphology of In(III)-SnO2/g-CN [3-4]. The findings reported in this study shows promising glimpse for designing a novel strategy to the development of ultrasensitive VOCs sensors working at low operating temperature . Refs:  ACS Omega 2, 2017, 3658;  J. Mater. Chem. A 5, 2017, 14134;  Sensors Actuators B: Chem. 253, 2017, 703;  Sensors Actuators B: Chem. 239, 2017, 364;  J. Mater. Chem. A 4, 2016, 1033.
Metal Oxides: Energy & Sensing : Yogendra Mishra
Authors : Sanjay Mathur, Yakup Gönüllü, Thomas Fischer
Affiliations : University of Cologne
Resume : In search of new energy sources, photoelectrochemical splitting of water to produce hydrogen is a viable approach to transform sunlight into chemical energy, which has triggered a quest for suitable photocatalysts. Among different semiconductor metal oxides, hematite (?-Fe2O3) has emerged as a promising photo-anode material for water oxidation since it is cheap, abundant, non-toxic and stable under photoelectrochemical conditions. Although it promises high theoretical photocurrent densities (11?14 mA/cm2), corresponding to a solar-to-hydrogen (STH) efficiency of 14-17 %, these values can hardly be attained since hematite suffers from high resistivity,] short lifetime of the photoexcited charge carriers, and short hole diffusion length (2-4 nm). Few of these limitations can be overcome by optimizing the nanostructure and electronic properties, as recently shown in a number of studies. In this study, we have focused on Interfacial modification of ?-metal oxide multilayer photoanodes deposited by plasma enhanced chemical vapor deposition (PE-CVD). Different mechanisms such as heterostructuring (Fe2O3//TiO2), nano-structuring, patterning of multilayering with different structure (bar structure or line structure) or graphene supporting were examined in this study. The bilayer electrode exhibited enhanced PEC responses in terms of a lower onset potential and a higher photocurrent density when compared to the single layer ?-Fe2O3 electrode. This enhancement was observed to be due to synergistic light absorption with the bilayer electrode, although charge carrier recombination occurred faster due to interfacial defect states. The incorporation of a graphene layer between the ?-Fe2O3/TiO2 double layer and the FTO substrate resulted in a doubling of the photocurrent, but lead to a loss of the synergistic effect between the two active metal oxide layers. However, depositing the graphene between the two metal oxide layers resulted in an even higher photocurrent, while retaining the enhanced onset potential of the double layer electrode. This enhancement was observed to be due to either the passivation of the oxide defect states or enhancement of the charge transfer between the two oxide layers.
Authors : Rishat Valeev, Andrey Chukavin, Artemii Beltiukov, Alexander Trigub, Vladimir Vetoshkin, Dmitry Petukhov, Alexander Alalykin, Ivan Elkin, Tatiana Kartapova
Affiliations : Physical-Technical Institute of Ural Brunch of RAS, Izhevsk, Russia; National Research Center ?Kurchatov Institute?, Moscow, Russia; Moscow State University, Faculty of Materials Science, Moscow, Russia
Resume : Copper- or manganese-doped zinc sulfide nanostructure arrays draw close attention due to their great promises in development of modern optoelectronic devices including light sources, optical touch panels or fluorescent labels. The work is focused on development of cheap pathways for formation of ordered ZnS:Cu(Mn) nanosized dot arrays formed by condensation of thermally evaporated ZnS and Cu2S powders in the pores of highly-ordered anodic alumina matrix in ultrahigh vacuum. Matrices with pore diameters of 40, 60 and 120 nm and thickness of interpore walls of 15 ( -5) nm were formed in aluminum plate and glass substrates. ZnS:Cu(Mn)@AAO composites were study by SEM, EDX, XPS, UV-VIS spectroscopy, X-Ray Diffraction and EXAFS-spectroscopy methods in comparison with ZnS:Cu(Mn) thin films. SEM studies shown that the form and arrangement of semiconductor nanostructures replicates well the form and arrangement of matrix channels. EDX analysis shown the penetration of deposited materials into pores to a depth of 3 micron. Luminescent and electroluminescent properties have been also investigated. The samples exhibit luminescence in a visible region depending on type and concentration of dopant atom and pore size of matrix. The work is supported by Russian Scientific Foundation (Grant ? 15-19-10002) and Russian Foundation of Basic Researches (Grant ? 16-48-180303).
Authors : Negar Gheshlaghi, Hadi Sedaghat Pisheh
Affiliations : Bilkent University
Resume : In recent years, an intense interest has emerged in the fabrication of semiconductor nanowires (NWs) based solar cells. Si NWs are potential candidates due to various advantages, including cost-efficiency, well-balanced electrical and optical properties, and well established processing techniques. They exhibit excellent antireflection behavior because of tunable optical absorption in a wide wavelength range originating from multiple scattering by NWs. On the other hand, CdSe based core/shell (core/alloy) QDs has a great potential in boosting light harvesting efficiency with the advantage of adjusting band gap energy to cover most of the visible light wavelength. Here we report, two fasil way in coating Si NWs with the CdSe/CdxZn1-xS (0≤x≤1) Core/Ternary shell nanocrystals to enhance light to current conversion. Well aligned p-Si NWs, were successfully synthesized by a Ag-assisted electroless etching technique which are uniformly distributed over the surface of p-type Si wafer. Si NWs coated with the synthesized QDs through spin coating and chemical bath deposition techniques. Investigate its device characteristics based on current–voltage (I–V), capacitance–voltage (C–V), and photo responsivity measurements.
Authors : Crina Anastasescu1, Cornel Munteanu1, Mihai Anastasescu1, Catalin Negrila2, Adriana Rusu1, Veronica Bratan1, Daniela Culita1, Maria Zaharescu1, Ioan Balint1
Affiliations : 1“Ilie Murgulescu” Institute of Physical-Chemistry of the Roumanian Academy, 202 Splaiul Independenţei, Bucharest 060021, Roumania; 2National Institute of Material Physics, 105 bis Atomistilor Street, 077125, POBox MG7, Bucharest-Măgurele, Romania
Resume : Newly developed SiO2 materials, prepared by sol-gel method, were proved to be able to absorb the light in a broad wavelength range due to formation of large number of optically active defects. Localized lattice defects, such Si3+ and oxygen-related imperfections (i.e. O-, O2-, O22-) formed under UV light irradiation in presence of O2, impact positively on both light absorbing properties and photocatalytic activity for methanol reforming. The SiO2 based materials were extensively characterized by a bunch of experimental techniques, such as SEM, AFM, FT-IR, UV-VIS, XPS, XRD and BET. High formation rate of photocatalytically produced H2/CO2 was observed over tubular SiO2 exposed to simulated solar light (AM 1.5) compared to other standard photo-active materials (i.e. TiO2-based compounds). The specific mechanism of methanol photo reforming over SiO2 was analyzed and some specific reaction paths were identified.
Authors : Claire Holtzinger1*, Michel Roux2, Paul-Henri Prévot3, Serge Picaud3, Nicolas Keller1
Affiliations : 1 ICPEES, Univ Strasbourg, CNRS, Strasbourg, France 2 IGBMC, CNRS, INSERM, Illkirch Graffenstaden, France 3 Institut de la Vision, UPMC, INSERM, Paris, France
Resume : Retinitis pigmentosa (RP) or age-related macular degeneration are degenerative diseases for which the degeneration of natural retinal photoreceptors is responsible for blindness of over 15 million people worldwide. Despite many therapeutics approaches, these diseases still remain incurable presently. One curative approach is the development of retinal prosthesis which consists in replacing the degenerated photoreceptors by a photoreceptive film to stimulate the partially-persistent neuronal network. Thus, our approach is to engineer inorganic photo-sensitive TiO2-based thin films for absorbing solar light and acting as artificial photoreceptors. Firstly, vertically aligned TiO2 nanotubes (NTs) were synthesized through an anodisation process of a Ti foil. A successful activation ex-vivo of retinal neurons on retinas from mice affected by RP was observed on bare TiO2 NTs under UV light. Films were pixellized and miniaturized by laser etching, allowing a subsequent surgical implantation in the eye. To increase light absorption and switch the NTs photo-response from the UV toward the visible light, graphitic-carbon-nitride (g-C3N4) was grafted on the NTs by thermal decomposition of a mixture of melamine and dicyandiamide. The photo-response of bare and g-C3N4 grafted-NTs were measured by electrophysiology when illuminated in the UV range (365 nm) and in the visible range in acellular condition in PBS. The results showed that both grafted and bare NTs exhibit a good photo-response in the UV part (approx 30 mV). However, whereas the photo-response of bare TiO2 is null in the visible range, grafted NTs showed a depolarization of about 1.4 mV. Ex-vivo activation of retinal neurons of mice is currently tested on g-C3N4 grafted NTs.
Photocatalysis & Water Splitting : Sanjay Mathur
Authors : Amit Bhatnagar*, Chella Santhosh*, Pratap Kollu**, Andrews Nirmala Grace***
Affiliations : *Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland **School of Physics, University of Hyderabad, Gachibowli, Hyderabad 500046, India ***Center for Nanotechnology Research, VIT University, Vellore-632014, Tamil Nadu, India
Resume : Nanocomposites have gained a wide interest in many applications including water treatment. In the present study, a variety of novel magnetic nanocomposites (MNCs), using graphene and cobalt ferrites, were synthesized by solvothermal process. In order to gain an insight into their physico-chemical properties, MNCs were characterized using X-ray diffraction, field emission-scanning electron microscopy, high resolution-transmission electron microscopy, vibrating sample magnetometer, X-ray photo spectroscopy, Brunauer?Emmett?Teller analysis and Fourier infrared spectroscopy. Further, the water purification studies were performed in order to examine the potential of MNCs in removing a wide array of aquatic pollutants (e.g. metal ions, dyes, pharmaceuticals). Experimental conditions were optimized to achieve the maximum removal of pollutants from water by synthesized MNCs. Modeling with the experimental data was also performed to describe and elucidate the mechanism of the process. The prepared MNCs exhibited considerable removal efficacy for studied pollutants. Regeneration experiments were also performed which revealed that prepared MNCs can be reused for multiple cycles without losing the original capacity. The results of this study revealed that the prepared MNCs are efficient in the removal of a wide array of aquatic pollutants thus, making them a potential candidate for water treatment.
Authors : Aadesh P. Singh, Björn Wickman, Anders Hellman
Affiliations : Division of Chemical Physics, Department of Physics, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
Resume : Conversion of solar energy into chemical fuel in a photoelectrochemical (PEC) devices requires an inexpensive and stable semiconductor photoelectrode materials with explicit control over the three main requirements in a single material system: 1) chemical stability 2) visible light absorption and 3) band edges matching to redox levels of water. This talk will summarize the results obtained for photoelectrochemical water splitting using metal oxide semiconductor such as BiVO4, TiO2 and α-Fe2O3. Our attention has been devoted to further modify these oxide semiconductors by using various strategies such as band edge engineering, material disordering, nano/micro engineering, surface/interface engineering to improve the performances of metal oxide-based materials, especially favoring the photoelectrochemical activity under simulated sunlight. Recently, a new engineering strategy, i.e., band re-alignment of BiVO4/TiO2 at the heterostructure was achieved by gas–phase modification technique of the top TiO2 layer which strongly promotes interfacial interaction at the junction and leads to an effective interfacial charge separation and charge transport. The modified BiVO4/TiO2 heterostructures exhibit significant enhancement of visible light absorption and improve the photoelectrochemical response. Keywords: metal oxides, energy conversion, charge recombination, photoelectrochemical, hydrogen production.
Authors : Ali Rauf, Md. Selim Arif Sher Shah, Pil Jin Yoo
Affiliations : School of Chemical Engineering, Sungkyunkwan University, South Korea SKKU Advanced Institute of NanoTechnology, Sungkyunkwan University South Korea
Resume : Self-doped semiconductors are promising class of highly efficient photocatalytic materials because the electronic properties can be controlled without sacrificing the chemical and thermal stability of the parent material. In this report, we report facile synthesis of Sn2+ self-doped SnS microparticles via a straight forward template-free hydrothermal route. Due to the ability to successful tune band structure while reducing defect generation, self-doped SnS could potentially serve as promising photocatalyst of waste water. Here, Sn2+ self-doping results in insertion of an energy level slightly below the conduction band of SnS, thereby decreasing the photoexcitation energy. Moreover, dopant sites can act as charge trapping sites, which can subsequently minimize problematic charge recombination. Synthesized materials were characterized by various spectroscopic, microscopic, and surface characterization techniques, all of which confirmed the formation of self-doped SnS. Sn2+ self-doped SnS photocatalyst successfully reduced carcinogenic Cr(VI) to the water-insoluble Cr(III) form under visible light illumination. The best photocatalytic efficiency was obtained from an optimal balance between increased numbers of trapping sites leading to longer charge carrier lifetime, and decreased distance between trapping sites, favoring charge recombination. We expect that similar methodologies can be applied to other non-stoichiometric semiconducting photocatalysts with tunable electronic properties and enhanced photocatalytic efficiency.
Authors : Burak TEKIN1,2, Mahir GULEN3,4, Seckin AKIN3,4, Erdi AKMAN4, Buket BEZGIN CARBAS1,2, Faruk OZEL3 and Savas SONMEZOGLU3,4
Affiliations : 1Department of Energy Systems Engineering, Karamanoglu Mehmetbey University, 70200 Karaman/TURKEY 2Conducting Polymers and Energy Applications Laboratory, Department of Energy Systems Engineering, Karamanoglu Mehmetbey University, 70200 Karaman/TURKEY 3Department of Metallurgy and Materials Engineering, Karamanoglu Mehmetbey University, 70200 Karaman/TURKEY 4Nanotechnology and R&D Laboratory, Department of Metallurgy and Materials Engineering, Karamanoglu Mehmetbey University, 70200 Karaman/TURKEY
Resume : In the current work, Cu2XSnS4 (X = Zn, Mn, Ni, Fe and Co) thin films were grown via one-step electrodeposition technique following sulphur-free annealing procedure at 500oC for 60 min and applied as counter electrodes (CEs) instead of high-cost platinum in dye-sensitized solar cell (DSSC). The physical, structural and electrochemical properties of CXTS thin films were studied by means of X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and cyclic voltammogram (CV) measurements. XRD and Raman analyses reveal that CXTS films possess fine crystallite structure with no secondary phases. Furthermore, the CXTS CEs demonstrate a densely packed and rough surface morphology, suggesting a large surface area and high conductivity. Moreover, CV analyses confirm that the electrocatalytic activities of the CXTS CE were ordered as Cu2CoSnS4>Cu2FeSnS4>Cu2ZnSnS4>Cu2NiSnS4>Cu2MnSnS4 due to the highest conductivity of Co, the better crystallite and the largest surface area of Cu2CoSnS4 CE. As a result, power conversion efficiencies were extracted from current density-voltage (J-V) as 3.0% 2.94%, 2.40%, 1.93% and 1.1% for Cu2CoSnS4, Cu2FeSnS4, Cu2ZnSnS4, Cu2NiSnS4 and Cu2MnSnS4 CEs based DSSCs, respectively. This can be ascribed to similar trend of electrocatalytic activities of CXTS thin films. As expected, the Cu2CoSnS4 shows the longest electron lifetime and best start/stop capability while Cu2MnSnS4 based cell exhibits the shortest electron lifetime and the lowest start/stop capability. The obtained results suggest that CXTS thin films synthesized via one-step electrodeposition technique can be promising candidate instead of Pt for low-cost and highly efficient DSSCs owing to their composition include earth abundant materials and their simple fabrication processes. Acknowledgement–This study was supported by the European Union through the COST Action MP1407 “Electrochemical processing methodologies and corrosion protection for device and systems miniaturization (e-MINDS)”, and by the Scientific and Technological Research Council of Turkey (TUBITAK Grant Number 115M762) who provided financial support for this research.
Authors : Kumud Malika Tripathi1, TaeYoung Kim1
Affiliations : 1Department of Bionano Technology, Gachon University, Seoul, Korea
Resume : Three-dimensional (3D) porous carbon structures have been widely investigated for myriad applications because of their versatile characteristics and inherent attractive properties such as light weight, low density, large surface area, high porosity and excellent electrical conductivity. Especially, the unique structure of carbon aerogels (CAs) with an interconnected framework, present many structural advantages like more accessible bulk and active surface, fast ion diffusion with enhanced mass transport rate. However the tedious synthetic conditions, need of template and high cost associated with potential environmental risks are the major obstacle for their large-scale processes. Herein, we report on a facile, efficient and green strategy for the synthesis of lightweight and highly porous carbon aerogels from bio-mass as low-cost precursor by hydrothermal treatment followed by post carbonization. The hierarchical porous structures is basically assembled by internally connected network of dendritic-linked carbon architecture and numerous macropores. The biomass-derived carbon aerogels hold considerable potentials as in low-cost, environmentally friendly and high performance and electrode material. These carbon aerogels shows outstanding capacitive performances of 120 F g-1 in two-electrode systems without using any activation agent.
Authors : David Beke, Klaudia Horváth, Katalin Kamarás, Adam Gali
Affiliations : Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary
Resume : Heterogeneous photocatalysis offers great potential for a variety of applications by converting photon energy into chemical energy. It has been established that the size and the shape of a semiconductor particle play an important role in photocatalysis. Quantum confinement often leads to a transition from continuous to discrete energy levels affecting remarkably the photocatalytic activity concerning the smallest nanoparticles (NPs). We synthesized silicon carbide (SiC) NPs with different size around the radius of exciton Bohr radius of SiC, in order to study the photocatalytic activity of a nanoparticle when energy levels transform from continuous to discrete levels. We found that SiC NPs with size below the twice of exciton Bohr radius show negligible activity, whereas larger particles become active. Our results clearly imply the importance of the size of semiconductor NPs for their photocatalytic activity. Furthermore we found that the colloid solution of smaller and larger NPs together shows enhanced photochemical activity with doubled efficiency with respect to the solution with large NPs only. The solution with mixed NPs did not show any long-time association or aggregation. A study of reaction kinetics revealed an energy transfer between the larger and smaller NPs and an adsorption-desorption controlled mechanism between the NPs that indicates a temporary formation of type II homojunction, i.e., the size differences of SiC NPs leads to varying band edges (or highest occupied and lowest unoccupied levels) with type II junction. This system demonstrates that fine tuning of size and surface termination of semiconductor NPs is inevitable to control its photocatalytic efficiency.
Poster Session II : YKM, IT, JA, OGS
Authors : Jinyoung Choi, ChulHee Lee, Tae Hong Lim, Mina Kim, Duk Young Jeon*, Keon Jae Lee*
Affiliations : Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology
Resume : Here we report instantaneous ligand exchange of Cu-In-S/ZnS core-shell quantum dots from hydrophobic ligands such as 1-octadecene (ODE) to hydrophilic ones such as 11-mercapto-1-undecanol (MUD) and 6-mercapto-1-hexanol (MCH) by using flash lamp exposure. We utilized light source to alternate heat source in traditional in-situ ligand exchange methods. The experiment was carried out by exposure of the quantum dots, in solution with high concentration of target ligands, flash lamp having 300nm to 800nm with wide wavelength width range. The output were examined by PL, UV Vis, and TCSPC devices, and high ligand exchange rate with minimal PL reduction was observed. The result shows that the flash lamp can be a promising way to alternate heat source in in-situ ligand exchange, remarkably reducing processing time of the process and greatly enhancing further experimental efficiency.
Authors : Min-Sang Lee(1), Parthiban Ramasamy(1), Sun-Tae Hwang(2), Bong-Min Choi(3), Young-Ki Lee(4), Jong-Soo Lee(1)
Affiliations : (1) Daegu Gyeongbuk Institute of Science and Technology ; (2) ODTech ; (3) QDM ; (4) NanoQnT
Resume : Colloidal semiconductor nanocrystals (NCs) are promising materials for the application in light-emitting devices, photodetection and solar energy conversion. Most of the previous fundamental studies and potential applications have been focused on Group II-VI QDs such as Cd-based chalcogenides. However, the toxicity associated with cadmium could impose critical constraints for practicable applications. Indium phosphide (InP) QDs have been suggested as the most promising candidate to replace Cd-based QDs due to their band gap tunability covering the entire visible range and narrow spectral bandwidth. Nevertheless, two major challenges need to be addressed to unlock the full potential of InP QDs in display application. Firstly, the size distribution in InP QDs need to be improved, which in turn will contribute to narrow emission linewidth and improve the color purity. Secondly, robust control over the particle size need to be achieved. In this work, we present an improved synthetic method to synthesize high quality Cd-Free NCs. The emission spectra of the QDs can be continuously controlled from 488 to 640 nm with narrow emission linewidth. We will also present a key parameters for fabrication of large area luminescent QD sheet for commercial optoelectronic devices (i.e., QLED displays).
Authors : Benjamin Kalas , Judit Nádor, Miklós Fried, Péter Petrik
Affiliations : Benjamin Kalas1, 2; Judit Nádor1; Miklós Fried1,3; Péter Petrik1, 1. Ellipsometry Group, Institute for Technical Physics and Materials Science, Centre for Energy Research, Hungarian Academy of Sciences, Konkoly Thege Miklós Str. 29-33, H-1121 Budapest, Hungary 2. Doctoral School of Physics, Faculty of Science, University of Pécs, Ifjúság útja 6, H-7624 Pécs, Hungary 3. Institute of Microelectronics and Technology, Óbuda University, Tavaszmezo u. 17, H-1084 Budapest, Hungary
Resume : We measured the adsorption of protein monolayers on different nanostructures using in situ spectroscopic Kretschmann ellipsometry. The nanostructures (e.g. platina nanoparticles, TiO2 nanotubes) were made by spin coating on glass substrates with a 40 nm thin gold layer. During the in situ investigations we used a home-made semi-cylindrical Kretschmann-Raether flow cell [1,2], so we could use the surface plasmon resonance (SPR) phenomenon to increase the sensitivity of the measurement . Compared to traditional SPR devices [2,3] the ellipsometer provided the phase information of the reflected beam, so we obtained more information that enabled us to increase the sensitivity by one order of magnitude compared to the case of having only amplitude information. The other advantage was that we could choose the SPR angle very precisely (within 0.1 degree) and we used a broad wavelength range from 400 nm to 1690 nm. Using a spectroscopic ellipsometer gave us the opportunity to build a complex optical model and use it to study the adsorbed protein layer quantitatively. The optical model we built successfully described the structure, so we registered in situ information about the adsorbed protein. The best nanostructure was identified with FEM (finite element) simulations, the protein adsorption was modeled also with RSA (random sequential adsorption) and then the numerical results were compared with the measurements.
Authors : Eliezer Fernando Oliveira, Ricardo Paupitz, Pedro Alves da Silva Autreto, Stanislav Moshkalev, and Douglas Soares Galvão
Affiliations : Gleb Wataghin Institute of Physics, State University of Campinas (UNICAMP), Campinas, SP, Brazil; Institute of Geosciences and Exact Sciences, São Paulo State University (UNESP), Rio Claro, SP, Brazil; Center of Natural Human Science, Federal University of ABC (CCNH-UFABC), Santo Andre, SP, Brazil; Center for Semiconductor Components, State University of Campinas (UNICAMP), Campinas, SP, Brazil
Resume : Graphene membranes present remarkable electronic and thermal properties, which make them a very promising material for several applications, such as in electronic devices. However, in spite these properties, good graphene/metal electrodes interfaces have been difficult to achieve. The structural graphene/metal mismatch drastically reduces thermal and electronic conductivities. One experimentally approach to address this issue has been high-temperature annealing . Significant improvements in thermal and electrical conduction has been obtained in this way, but the underlying mechanism behind these processes are still elusive. In this work, using fully atomistic reactive molecular dynamics simulations (FARMD), we realistically model the system in order to observe the annealing influence in the interaction between multi-layers graphene and metallic electrodes (nickel and gold). Our results show that the annealing produces an upward and downward movement of the graphene membranes, which lead to atomic polishing-like phenomena and makes the metallic electrode surface flatter. This atomic planarization improves the coupling between graphene and the metallic electrodes and, consequently, contribute to better thermal and electronic conductivities. Acknowledgment: We thank the Brazilian agency FAPESP financial support and the Center for Scientific Computing (NCC/GridUNESP) of the São Paulo State University (UNESP).  V. A. Ermakov, et al., Nanotechnology 24 (2013) 155301.
Authors : Judit Nador 1, Benjamin Kalas 1, Andras Saftics 1, Levente Illes 1, Carmen Moldovan 2, Mariuca Gartner 3, Boglarka Kovacs 1, Miklos Fried 1, Ferenc Vonderviszt 1 4, Peter Petrik 1
Affiliations : 1: Institute for Technical Physics and Materials Science, Centre for Energy Research, Hungarian Academy of Sciences, Budapest, Hungary; 2: National Institute for Research & Development in Microtechnologies, Bucharest, Romania; 3: “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, Bucharest, Romania; 4: University of Pannonia, Veszprém, Hungary
Resume : In modern technology the developments in environmental areas become more important and current. Freshwater stocks and pollution are in the most relevant topics, as they can be crucial in the future of humankind. Within the “WaterSafe” international project, we take part in the development of a device for detecting various water pollution molecules, mainly heavy metal ions. The sensor surface can be a mix of dielectrics, nanostructures or genetically modified bacterial flagellar filaments (FF) that have specific binding sites for the target molecules. The adsorption of the molecules to the immobilized filaments induces a change in the conductance of the electronics which can indicate the presence of the pollution. The main aim of our group is to create the sensing layers by immobilizing the FFs on the sensor surface. Either genetically modified FFs were used, which have sulfur molecules on their surfaces, thus they can develop covalent bonds with the gold surface, or unmodified FFs were immobilized using a chemical cross-linker molecule (DSP). Various titanium-oxide-based surface nanostructures were prepared on the substrates in order to facilitate the adsorption of the FFs. The coverage of the FF layers is investigated in situ by plasmon enhanced spectroscopic ellipsometry and ex situ by AFM, SEM and ellipsometric scanning of the surfaces.
Authors : Ricardo Paupitz
Affiliations : Institute of Geosciences and Exact Sciences, Sao Paulo State University - UNESP, Brazil
Resume : Fullerenes and nanotubes are between the great discoveries of materials sciences in the last few decades and motivated many studies regarding the search for new materials. One option to be explored is the search for materials with nanostructure geometrically similar to that found for carbon based materials but based in other elements, like Si, Ge, or B and N, or As and Ga, etc. In the present work, we investigate some of these interesting possibilities, our study is focused in the possible existence of closed cage molecules with architecture inspired by the usual fullerenes, but based in other elements. We considered atoms from three different columns of the periodic table of the elements, namely the column of boron, of carbon and of nitrogen. The tests include architectures similar to that of the C60, C20 and that of the recently experimentally synthesized B40. Our calculations indicate that a few of these clusters can be stable at room temperature. Some of these structures are stable only when passivated by hydrogen atoms in the exterior region. We also investigate the electronic structure of these clusters including their absorption and emission spectrum as well their reactivities, calculated by the Fukui indices.
Authors : S. Alberti, V. Caratto, F. Locardi, P. Lova, D. Comoretto, M. Ferretti
Affiliations : Department of Chemistry and Industrial Chemistry, University of Genoa, Genoa 16146, Italy
Resume : Nanometric TiO2 and ZnO are the most preferable photocatalytic semiconductor materials, due to their excellent chemical stability, environmental sustainability, nontoxicity and low cost. However, they are limited as sunlight-driven photocatalysts, due to their band gap (ca. 3.2 eV for both), which a photon with wavelength ≤ 400 nm, which means that a UV light source is mandatory. A possible way to overcome this limitation is using a supporting material such as a persistent luminescence material (PeLM). In fact, the PeLM is able to be charged with either natural or artificial radiation and, glowing in darkness, provides the necessary photons to the catalyst (1). The coupled system has applications in wastewater treatment, being particularly effective in the treatment of contaminated water with pharmaceuticals and in turbid wastewaters. A solid state synthesis was performed to obtain the coupled system: amorphous TiO2 powders, ZnO powders (2) and PeLM powders were suspended together in water, dried in an oven at 105 °C for 12 hours and eventually subjected to a thermal treatment for 1 hour at 350°C. Several samples were prepared and chemical physical characterized, and their photocatalytic activity was evaluated using a methylene blue solution. The resulting best samples were also tested on a turbid solution and an aqueous solution contaminated with an antibiotic. 1. Locardi F. et al. Catalysis Communications 2016, 74, 24-27 2. Lova P. et al. Physica Status Solidi (c) 2015, 12 (1-2), 158-162
Authors : Yingjie Chai1, Maria Luisa Grilli2*, Daniele De Felicis3, Riccardo Moscatelli3, Guohang Hu1, Hongbo He1, Angela Piegari2, Edoardo Bemporad3, Jianda Shao1, Anna Sytchkova1*
Affiliations : 1Key Laboratory of High Power Laser Materials, Shanghai Institute of Optics and Fine Mechanics, Shanghai (CAS), 390 Qinghe Road, Jiading 201800, China; 2ENEA - Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Optical Coatings Group, Casaccia Research Centre, via Anguillarese 301, 00123 Roma, Italy; 3University "Roma Tre", Engineering Department, via della Vasca Navale 79, 00146 Rome, Italy *firstname.lastname@example.org, email@example.com
Resume : Metal and dielectric nanostructures play an important role in several fields such as nanophotonics, optoelectronics, solar cells and sensing. Nanostructured arrays of artificial atoms may be obtained by different methods as reported in the literature. Many of lithographic methods used for manufacturing of these so-called metamaterials rely on using of polymers. In this work we investigate the optical properties of polymethyl metalacrylate (PMMA ) films obtained by spin coating deposition on glass and glass/ITO substrates. The refractive index and extinction coefficient were investigated as a function of the deposition conditions and of post-deposition ion-beam treatment. Focus Ion Beam (FIB) milling was used to fabricate nanostructured arrays on the PMMA surface which is used as a template for the fabrication of optical multilayers. A thin ITO film was deposited by radio frequency sputtering on a glass substrate prior to PMMA deposition in order to avoid excessive surface charging upon the FIB bombardment which may cause polymer degradation. Different concentrations of PMMA in anisole solvent were used for obtaining PMMA films of various thicknesses in the range 200-800 nm, aiming to maximize films' thickness accuracy and reproducibility of optical properties. The optical constants (refractive index and extinction coefficient) and thickness of PMMA films were inferred by fitting transmittance and reflectance spectra measured by a commercial spectrophotometer. The structural change of the polymer upon ion bombardment was observed by SEM in the vicinity of the treated areas and the effective refractive index of the treated nanostructured PMMA was investigated.
Authors : P. Hönicke, B. Beckhoff
Affiliations : Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
Resume : A reliable and non-destructive depth dependent characterization of layer stacks is an important topic in many fields of research. The metrological challenges to sufficiently characterize such systems with respect to their structure-property relationships require a further development of the current analytical techniques in parallel to the quickly increasing complexity of systems to be analyzed. A combined analysis using Grazing Incidence X-ray Fluorescence (GIXRF) and X-Ray Reflectometry (XRR) as proposed by de Boer  has already been shown to be capable of contributing to the in-depth analysis of nanoscaled materials. Here, the general approach to model the two experimental data sets using the density ρ, thickness d and roughness σ of each layer as the parameters can quickly result in numerous degrees of freedom and thus unreliable results . In this work, XRR is combined with PTB’s reference-free GIXRF , providing a direct access to the mass depositions (ρd) of the present materials. This allows for a significant reduction of the degrees of freedom within the combined GIXRF-XRR modeling and thus improves the characterization reliability of the methodology. Employing the in-house built instrumentation  and radiometrically calibrated detectors at the laboratory of the PTB at the BESSY II synchrotron radiation facility, the reference-free GIXRF-XRR method is demonstrated using the example of Al2O3-HfO2 nanolaminate stacks. References  D. de Boer et al., Spectrochim. Acta B 46(10), 1323 (1991).  P. Hönicke et al., Phys. Stat. Solidi A 212(3), 523 (2015).  M. Müller et al., Materials 7(4), 3147 (2014).  J. Lubeck et al., Rev. Sci. Instrum. 84, 045106 (2013).
Authors : G.M. Telbiz, V.P. Yashchuk1, E.A. Tikhonov2
Affiliations : L.V. Pisarzhevsky Institute of Physical Chemistry NAS of Ukraine, 31 Nauki av., Kyiv-03039; 1Taras Shevchenko National University of Kyiv, 4b Acad. Glushkova av. Kyiv - 01601 2Institute of Physics NAS of Ukraine, 46 Nauki av., Kyiv-03039
Resume : Studies on the fabrication of sol-gel optical composite materials for photovoltaic devices and (or) planar optical waveguide are continuously caring attention over the years because this material has numerous applications in the field of microelectronics and optoelectronics. However, for oxides many difficulties have to be faced to obtain defect-free, high fidelity, structurally stable films for application in devices. We studied factors strongly influence on the characteristics of the thin hybrid film which would help to tune their quality of surface and body, developed the self-assembled technology based on the sol-gel method to fabricate high-quality hybrid nanocomposite films using network-forming oxides such as silica or titania that allows to variate different types of inclusions. Increase of concentration barrier of quenching of the luminescence and create conditions for waveguide propagation of laser radiation in the film will be the factors significantly influence the film luminescence efficiency and consequently the final laser performance. The possibility of controlling dye locations allowed increasing its concentration several orders compared to conventional materials without reducing the quantum yield of luminescence[1,2]. Preliminary results show that these photosensitive nanostructured films demonstrate nonlinear optical response under excitation of optical pulses of nanosecond duration. The ability of ultrafast excited-state dynamics of composite films containing Rh6G was examined for their potential use as the photonic layer in an all-optical switching device and have obtained the recording of a dynamical grating in a single-pulse regime. Moreover for both films, we observed lasing, which appears as radiation of the central beam that consists from enhanced luminescence (along with track) and occurring due to the distributed feedback grating of enhancement created by the oncoming waves of the enhanced luminescence. Two order reducing the threshold pump intensity and changing the shape of lateral beams under changing TiO2 matrix instead SiO2 one is evidence of formation the waveguide amplifier in the TiO2 film. These results show possibility high-quality lasing on the basic mode of a waveguide that forms the central beam. This work would help on the manufacturing of mesoscale surface patterning of other hybrid films of mixed oxides for the perspective application as active optical materials.  A. Kazakevičius, L. Valkunas, E. Leonenko, G. Telbiz and V. Gulbinas Insights into the mechanism of enhanced Rhodamine 6G dimer fluorescence in mesoscopic Рluronic-silica matrixes // Journal of Phys.Chem. C (2015), 119, 19126−19133 . G. Telbiz, E. Leonenko, M. Dvoynenko Оptical properties of Rh6G molecules ordering in the silica- and titanium dioxide mesoscopic sol-gel films//Molecular Crystals and Liquid Crystals (), vol. , –  G. Telbiz, S. Bugaychuk, E. Leonenko, L. Derzhypolska, V. Gnatovskyy, I. Pryadko. “Ability of dynamic holography in self-assembled hybrid nanostructured silica films for all-optical switching and multiplexing”, Nanoscale Research Letters, 10:196, p. 1-7 (2015).
Authors : Naixiang Wang, Feng Yan
Affiliations : Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China.
Resume : Organic electrochemical transistors (OECT) have been extensively studied as an effective platform for chemical and biological sensing applications, based on their advantages on low-voltage operation, good biocompatibility and interaction with aqueous medium. However, conventional OECTs are normally fabricated in the scale of millimeter or larger, resulting in a slow response time for device operation. To overcome this problem, here we develop a novel approach to miniaturize OECT by using photolithographic technique. The channel of OECTs could be reduced to several to twenty microns therefore the speed of device response could be raised up to order of 10^-5 s in aqueous medium. Due to the improvement in transient response time of the micro OECT device, alternating current (AC) is possible to be introduced for device operation. Combined with lock-in amplifier, the small AC channel signal could be precisely extracted from an extremely noisy environment, which provides the possibility to enhance the sensing capability of the OECT devices in complex situations. The detection limit of dopamine, an important neuro transmitter within the central nervous system, is down to 10-9 M. In conclusion, we introduce a simple and easy-to-fabricate process for miniaturization of OECT devices to the cellular dimensions. The advantage of fast transient response makes the AC-driven micro OECT capable of in-situ cell activity monitoring and associated chemical sensing applications.
Authors : Robson Rosa da Silva1, Deivy Wilson1, Hernane da Silva Barud2, Sidney José Lima Ribeiro3, Osvaldo Novais de Oliveira Jr.1
Affiliations : 1 -São Carlos Institute of Physics,University of São Paulo, CP 369, 13560-970 São Carlos - SP,Brazil 2 - University Center of Araraquara, UNIARA, 14801-340 Araraquara-SP, Brazil 3 -Institute of Chemistry, São Paulo State University, CP 355, 14801-970 Araraquara-SP, Brazil
Resume : Bacterial cellulose (BC) membranes are produced by some bacteria such as the specie Gluconacetobacter xylinus and commercially used as wound dressing. BC membranes have high crystalline 3D network composed by pure cellulosic fibers with diameters below 100 nm and lengths larger than 3 μm. BC membranes fulfill several pre-requisites as ideal material for biological interface. BC membranes have good adherence to the wound, enable excellent water vapor permeability, and constitute physical barriers for microorganisms. In particular, BC membranes have been poorly explored as substrate for biosensensing materials based on sensors. Voltammetric sensors based on screen-printed carbon electrodes (SPCE's) built on BC membranes may have an incredible potential to be used in biology–device interface. As a proof-of-concept, we evaluated the voltammetric behavior of well-known model analytes in SPCE's printed on BC membranes. The SPCEs were home fabricated over dried BC membranes substrate using a screen printer machine IMAH and appropriate stencil designs fabricated on polyester screens (150 meshes). First, a carbon layer was deposited on BC substrate using a pattern comprising the electrical contacts and the working and counter electrodes. They were obtained SPCEs with a working electrode area of 0.09 cm2 and films thickness (determined by profilometry measurements, n=9) of 8.7 µm for Ag/AgCl and 9.2 µm for carbon films. By using BC membrane as substrates for SPCE, we successfully detected uric acid, pyrogallic acid and ferrocyanide and ferricyanide ions model analytes dissolved in aqueous solutions at concentrations up to 60 ppm, 1 mM and 5 mM, respectively. We also evaluated the modification of SPCE working electrode with inkjet printed metallic nanoparticles and tyrosinase enzyme. Taking advantage of their remarkable biocompatibility, BC membranes can be considered an excellent choice as an emergent biopolymer for the development of future implantable biosensors.
Authors : Sergey Zavatski, Nadia Khinevich, Kseniya Girel, Vitaly Bandarenko, Hanna Bandarenka
Affiliations : R&D Laboratory "Materials and Structures of Nanoelectronics", Belarusian State University of Informatics and Radioelectronics, 6 Brovka st., Minsk 220013 Belarus.
Resume : Gold nanoparticles (Au NPs) were formed by electroless deposition of gold on meso- and macroporous silicon with different porosity from an aqueous solution of potassium dicyanoaurate(I) and hydrofluoric acid. Deposition time was varied in the range from 30 to 70 minutes. The morphology and optical properties of Au NPs were analyzed using SEM, reflection and Raman spectroscopies. Au NPs were found to deposit both on meso- and macroporous silicon according to the layer island mechanism of thin film growth. Analysis of the reflection spectra allowed to determine a location of the surface plasmon resonance band and its intensity for each sample. We also revealed that variation of the porous silicon porosity and the gold deposition time led to different enhancement of the Raman signal from rhodamine 6G (R6G) in micromolar concentration adsorbed on the surface of the gold-coated porous silicon. The measured SERS-spectra correlated with the morphology of Au NPs, porous silicon type and regimes of the gold deposition. The greatest enhancement of Raman signal from R6G molecules was provided by gold-coated macroporous silicon. Its intensity was twice more than that from Au NPs on mesoporous one.
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|09:00||Plenary Session - Main Hall|
Nanoelectronic Sensing Devices : YKM, IT, JA, OGS
Authors : Susanne Hoffmann-Eifert
Affiliations : Peter Gruenberg Institute and JARA-Fit, Forschungszentrum Juelich GmbH, 52425 Juelich, Germany
Resume : Redox-based memristive devices (ReRAM) based on ultrathin metal/metal oxide/metal stacks are considered as one of the most promising approaches for future high-density non-volatile data storage and beyond-von Neumann architectures including logic-in memory and neuromorphic applications . Fast switching events on time scales of nanoseconds combined with data retention times in the order of ten years are enabled by the nanoscale redox-type reactions in the ReRAM cells that control the addressable resistance states. Therefore, ReRAM cells can only be understood if their mixed ionic electronic structure is considered. This applies to the material and stack design as well as to the modelling approaches. In other words, differences in the oxidation enthalpies as well as oxygen diffusion coefficients in the respective materials become equivalently important as have been the band gap and permittivity values for capacitive storage devices in the past. In this talk, I’ll summarize different actual trends in the design of materials stack combinations for memristive and for selector elements. Furthermore, I’ll introduce concepts for their high density integration spanning the range from crossbar and pillar-type cells to vertical 3D ReRAM approaches.  D. Ilemini, R. Waser, ‘Resistive Switching - From Fundamentals of Nanoionic Redox Processes to Memristive Device Applications’, Wiley-VCH, United Kingdom (2016)
Authors : (1) S. Dell’Elce, (2) F. Liscio, (1) A. Kovtun,(3) S. Allegri, (4) H. W. Amenitsch, (1,5) A. Liscio, (3) F. Stellacci, (1) V. Palermo.
Affiliations : 1) ISOF-CNR, Bologna, Italy; 2) IMM-CNR, Bologna, Italy; 3) Institute of Materials EPFL, Losanne, Switzerland; 4) Institute of Inorganic Chemistry, Graz University of Technology, Graz, Austria; 5) ISC-CNR, Roma, Italy.
Resume : Here we describe the self-assembly of metal-organic nanoparticles forming 2- and 3- dimensions mesoscopic high-ordered superstructures solvent-triggered using solvent vapour annealing (SVA). We used nanometric, atomically monodisperse molecular complexes with formula Ag44(SR)30 (a.k.a. intensely and broadly absorbing nanoparticles: IBANs) of silver as building blocks. IBANs feature a radius of ≈ 2 nm, and a unique combination of bulk-like and molecular properties, halfway between small inorganic molecules and larger monolayer-protected metal nanoparticles. Their unique optical properties allow to study their behaviour in solution and on surfaces using optical spectroscopy; though, their application in bioscience, nanophotonics, nanoelectronics and light-harvesting is limited due to their reduced thermal and chemical stability. Stable for months in solution, IBANs can pack forming macroscopic 3D crystals with triclinic structure. By heating or exposure to suitable solvents, we rearranged the packing of such building blocks into 2-dimensional monoatomic layers, stabilized on both sides by a layer of thiols, forming stacked structures with high periodicity across the plane. We combined UV-Vis spectroscopy and light scattering in solution with AFM and X-rays scattering in solid to follow the structural transformation of such materials at the nanoscale. The kinetics and the mechanisms of degradation were studied in-situ by Mass Spectroscopy (MS) and X-ray Photoemission Spectroscopy (XPS) in ultra-high vacuum (p = 10-9 mbar). GISAXS/GIWAXS measurements performed with synchrotron light clearly showed the presence of a crystalline structure with different Van der Waals packings.
Authors : Sreetosh GOSWAMI, Hariom JANI, Soumya SARKAR, Sreebrata GOSWAMI, Christian NIJHUIS, Jens MARTIN, T Venky VENKATESAN
Affiliations : National University of Singapore;National University of Singapore;National University of Singapore; Indian Association for the Cultivation of Science; National University of Singapore;National University of Singapore;National University of Singapore
Resume : Charge transport through organic resistive memory devices has been an arena of intense research. Here we explore the transport properties of a film made of a Ru-complex displaying memristive response at room temperature, i.e. a pinched hysteresis loop in the current-voltage-characteristics J(V). In-situ Raman and UV-Vis spectroscopic measurements establish that the switching in film conductance is controlled by the ligand redox states of the film molecules, while the counter ions account for the hysteresis. As temperature is lowered, the hysteresis in J(V) gradually decays below 145K till ~5K where it completely quenches. In the temperature range of 135K to 110K, we observe well resolved conductance plateaus at different applied bias with sharp transition in between them. The number of plateaus N in the J(V) follows the empirical rule of N= d[nm]/5 where d is the film thickness in nm. The conductance plateaus correspond to a correlation of [J0]^N, with J0 = current of the first plateau. Each of the plateaus are characterized by in-situ Raman spectroscopy as well as photoluminescence (PL) measurement, both of which exhibit sharp transitions corresponding to the switching observed in J(V). PL and Raman peak intensities scale as N x I0, where I0 is the PL/Raman intensity of the first plateau. These observations indicate a layer by layer electron doping in the film where layers of around 5 nm get doped sequentially. This is an unprecedented result in an amorphous film.
Authors : Paola Lova, Giovanni Manfredi, Alberto Servida, Davide Comoretto
Affiliations : Università degli Studi di Genova, Dipartimento di Chimica e Chimica Industriale, via Dodecaneso 31, 16146, Genova (GE), Italy
Resume : We report on the sensing of volatile organic compounds including alcohols and aromatic molecules by multi-layered photonic crystals made of commodity polymers such as polystyrene, cellulose acetate, and poly (p-phenilenoxide). The simple kinetical analysis of the optical response of these microstructured nanocomposites to the vapours exposure leads, on one hand, to label-free colorimetric sensors, suitable for the quali-quantitative analysis of volatile organic compounds, and on the other, to the determination of the analyte diffusion parameters into the polymer multilayers. We will also show that this simple optical method provides a new powerful tool for the in-situ assessment of the molecular diffusion coefficient in polymer films, widely used in food packaging and for the encapsulation of optoelectronic devices by mean of simple UV-VIS spectroscopy.
Authors : K. Kertész1, G. Piszter1, Zs. Bálint2, Z. E. Horváth1, L. P. Biró1
Affiliations : 1 Institute of Technical Physics and Materials Science, Centre for Energy Research, 1525 Budapest, PO Box 49, Hungary (http://www.nanotechnology.hu/) 2 Hungarian Natural History Museum, Baross utca 13, H-1088 Budapest, Hungary
Resume : The preparation of complex nanosized 3D structures requires highly developed and expensive laboratory techniques. As an alternative, natural material is available in large quantities and various structures, with properties that may approximate the artificial ones . It was shown that the biological photonic crystal structures occurring in butterfly wing scales can be used as sensing material . The color of certain butterfly wings is determined by two components: pigments and structural coloration . The photonic nanoarchitectures are built up of chitin and air, and their coloration varies if small changes occur in the refractive index of the medium, for example if mixing vapors in the air. This generates a variation perceptible with optical spectroscopy. Measuring the reflected light spectrum, one can determine the concentration of the vapors in the air. As the gas sensing experiments needs high reproducibility, we tested the stability of the wing coloration in the case of Polyommatus icarus butterflies collected from a certain population  and from a large temporal and spatial range. Also it was tested the alteration of the color when heat shock was applied on pupal stage of the butterflies . Our latest results on gas/vapor sensing will also include measurements on functionalized wings.  L.P. Biró, J.P. Vigneron, Laser Photon. Rev. 5, (2011)  R.A. Potyrailo et al. Nat. Phot. 1, (2007)  Piszter et. al. Plos One 11, (2016)  Kertész et. al. Sci. Rep. 7, (2017)
Authors : Tian Carey 1, Stefania Cacovich 2, Giorgio Divitini 2, Jiesheng Ren 3, Aida Mansouri 4, Jong M. Kim 1, Chaoxia Wang 3, Caterina Ducati 2, Roman Sordan 4, Felice Torrisi 1
Affiliations : 1. Cambridge Graphene Centre, University of Cambridge, UK; 2. Department of Materials Science and Metallurgy, University of Cambridge, UK; 3. Key Laboratory of Eco-Textile, Jiangnan University, Wuxi, 214122, China; 4. L-NESS, Politecnico di Milano, Via Anzani 42, 22100 Como, Italy;
Resume : Solution processing of graphite and other layered materials provides low-cost inks enabling printed electronic devices . However, the limited quality of the 2d material inks, the complexity of the layered arrangement, and the lack of a suitable dielectric 2d ink  has impeded the fabrication of active field effect devices with fully-printed 2d heterostructures . In this work we demonstrate fully inkjet printed 2d material active heterostructures using graphene and hexagonal-boron nitride (h-BN) inks, and use them to fabricate all inkjet printed flexible and washable field effect transistors (FETs) on textile, reaching a field effect mobility of μ ~ 91 ± 29 cm2 V-1 s-1 on polyester fabric, at low operating voltages (< 5 V). The devices maintained their performance even under ∼ 4% tensile strain and showed stable operation for periods up to 2 years, indicating the two-fold role of the h-BN layer as a flexible dielectric and encapsulant. Our graphene/h-BN FETs are washable up to 20 cycles, which is ideal for textile electronics. The viability of our process for printed and textile electronics is demonstrated by fully inkjet printing electronic circuits, such as reprogrammable volatile memory cells, complementary inverters, and OR logic gates with graphene/h-BN FETs. References  Torrisi, F. et al. Inkjet-printed graphene electronics. ACS Nano 6, 2992–3006 (2012).  Kelly, A. G. et al. All-printed thin-film transistors from networks of liquid-exfoliated nanosheets. Science, 356, 69–73 (2017).  Torrisi, F. & Coleman, J. N. Electrifying inks with 2D materials. Nat. Nanotechnol. 9, 738–739 (2014).
Authors : Yaw S. Obeng, Christopher E. Sunday, Lin You, Joseph Kopanski
Affiliations : Engineering Physics Division Physical Measurement Laboratory National Institute of Standards and Technology Gaithersburg, MD 20899-8101
Resume : Recent advances in technological and materials innovations have shifted the architecture of integrated circuits from two-dimensional planar to three dimensional (3D) systems, with stacked chips. The performance demands of these 3D-SIC devices seem to be at odds with the reliability needs because while the emerging devices are expected to operate at higher current densities, they have lower voltage tolerances at higher electric fields. With this change, the reliability of the electronic circuitry has shifted from being transistor-dominated to interconnect-dominated challenges such as resistivity changes; stress induced unexplained early failures; electromigration, etc. The problems are by-and-large materials. Unfortunately, traditional metrology has been unable to adequately address the measurement needed to in-situ characterize the underlying failure mechanism. We have introduced and demonstrated the application of broadband radio frequency dielectric spectroscopy (BDS)-based metrology, in addressing the metrology gap. The BDS leverages the well-known concepts from the interaction of electromagnetic radiation matter, except that microwaves induce molecular rotations instead of vibronic spectroscopy (i.e., UV-Visible-IR spectroscopy) in solid state materials. BDS measurements provide both electrical and chemical information to guide the reliable integration of material into more solid designs for the intended applications, and for monitoring the manufacturing process. These RF-dielectric material interactions are reasonably granular and uniquely suitable for studying the buried structures and material interfaces inherent in integrated circuit devices. In this talk I will review several BDS applications in determining the dominant failure mechanisms in disparate reliability issues of emerging 3D integrated electronic devices.
Authors : Joakim Vester-Petersen , Rasmus E. Christiansen , Brian Julsgaard , Peter Balling , Ole Sigmund ,Søren P. Madsen 
Affiliations :  Department of Mechanical Engineering, Aarhus University, Inge Lehmanns Gade 10, 8000 Aarhus C, Denmark,  Department of Mechanical Engineering, Technical University of Denmark, Nils Koppels Alle ?, Building 404, 2800 Kgs. Lyngby, Denmark,  Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
Resume : This work addresses efficiency improvements of solar cells by manipulating the spectrum of sunlight to better match the range of efficient current generation. The intrinsic transmission losses in crystalline silicon can effectively be reduced using photon upconversion in erbium ions in which low energy photons are converted to higher energy photons able to bridge the band gap energy and contribute the energy generation. The upconversion process in erbium is inefficient under the natural solar irradiation, and without any electric field enhancements of the incident light, the process is negligible for photo-voltaic applications. However, the probability for upconversion can be increased by focusing the incident light onto the erbium ions using optimized metal nanostructures [1, 2, 3]. The aim of this work is to increase the photon upconversion yield by optimizing the design of metalic or dielectric nanostructures placed on top of an erbium doped thin film. To achieve this goal, topology optimization  is used to create 2D cross-sectional designs of nanostrips able to focus the incident light into the film. The infrared absorption band of erbium is sought utilized by optimizing for multiple excitation wavelengths while also including production inaccuracies directly within the optimization process . The governing physics is modeled using Maxwell equations in a finite spatial domain truncated using periodic or scattering boundary conditions.  S. R. Johannsen et al. ?Up-conversion enhancement in Er3+ doped TiO2 through plasmonic coupling: Ex- periments and finite-element modeling?. In: Appl. Phys. Lett. 106.5 (2015), p. 053101. DOI: 10.1063/1. 4907415.  S. P. Madsen et al. ?Optimizing Plasmonically Enhanced Upconversion?. In: Energy Procedia 77 (2015), pp. 478?486. DOI: 10.1016/j.egypro.2015.07.068.  H. Lakhotiya et al. ?Plasmonically enhanced upconversion of 1500 nm light via trivalent Er in a TiO2 matrix?. In: Appl. Phys. Lett. 109.26 (2016), p. 263102. DOI: 10.1063/1.4972785.  J. S. Jensen et al. ?Topology optimization for nano-photonics?. In: Laser Photonics Rev. 5.2 (2011), pp. 308? 321. DOI: 10.1002/lpor.201000014.  J. Vester-Petersen et al. ?Topology Optimized Gold Nanostrips for Enhanced Near-infrared Photon Upconversion?. Submitted, 2017.
Perovskites & QDs : Yogendra Mishra, Oliver Schmidt
Authors : L. Polavarapu
Affiliations : 1Chair of Photonics and Optoelectronics Group, Department of Physics and CeNS, Ludwig-Maximilians-Universität Munchen, Munich, Germany 2Nanosystems Initiative Munich (NIM), Munich, Germany
Resume : Perovskite nanocrystals (NCs) are receiving great deal of attention due to their unique optoelectronic properties . Among these, high fluorescence quantum yields (QYs), tunable emission colour across visible range, large absorption cross-section, large diffusion lengths, and long recombination times make them potential candidates for photovoltaic and light emitting applications. In this presentation, I will introduce facile methods for shape-controlled synthesis of perovskite NCs ranging from nanocubes, to nanoplatelets, and nanowires [2-4]. The tunable optical properties of perovskite NCs by their dimensions and control over halide ion composition will be discussed. References  l. Polavarapu,* B. Nickel, J. Feldmann, A. S. Urban, Adv. Energy Mater. 2017, DOI: 10.1002/aenm.201700267  Y. Tong, F. Ehrat, W. Vanderlinden, C. Cardenas-Daw, J. K. Stolarczyk, L. Polavarapu, * Urban, A. S. ACS Nano 2016, 10, 10936-10944.  V. A. Hintermayr, A. F. Richter, F. Ehrat, M. Döblinger, W. Vanderlinden, J. A. Sichert, Y. Tong, L. Polavarapu,* J. Feldmann, A. S. Urban, Adv. Mater. 2016, 28, 9478-9485.  Y. Tong, E. Bladt, M. F. Aygüler, A. Manzi, K. Z. Milowska, V. A. Hintermayr, P. Docampo, S. Bals, A. S. Urban, L. Polavarapu,* J. Feldmann, Angew. Chem. Int. Ed. 2016, 55, 13887-13892.
Authors : Z. Aziz*, D. Djoher, O. Youb, B. Bouadjemi, T. Lantri and Y. Sefir
Affiliations : Laboratory of Technology and solid properties, Faculty of Sciences and Technology, Abdelhamid Ibn Badis University, BP 227 Mostaganem 27000, Algeria
Resume : First-principles calculations have been performed on the structural, electronic and elastic properties of the Pm3m cubic CeCoO3 compound, by means of the Density Functional Theory and the Linearized Augmented Plane Waves (FP-LAPW) method with spin polarization. For the calculations, the exchange and correlation potentials were included through the Generalized Gradient Approximation (GGA) with correlation effect correction (GGA + U). The structural properties, including lattice constant are found to be in close agreement with the reported experimental data, the calculated densities of states presented in this study identify the metallic behavior for both approaches. In addition, the ferro-magnetic phase is found to be energetically more favorable than non-magnetic and anti-ferromagnetic phases Finally ,we have evaluated the elastic constants (Cij), the young’s modulus (Y), poison’s ratio and anisotropic factor (A).
Authors : O.V. Chukova, S.G. Nedilko, A.A.Slepets, S.A. Nedilko, T.A. Voitenko
Affiliations : Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska Str., UA-01601 Kyiv, Ukraine
Resume : Rare earth orthovanadates have very important applications in various fields involving chemistry and biology, luminescent nanoparticles and light transformers. These compounds are chemically stable and non-toxic. Their range of biological applications includes fluorescent probes for single molecule tracking, drug development, protein detection and fluorescent bio labeling. It is expected that intensities of their luminescent emission can be effectively increased with the A2+ modifying cations. The investigated nanoparticles were prepared by aqueous nitrate-citrate sol-gel synthesis route using citric acid as a complexing agent. XRD study have shown that synthesized samples have monoclinic or tetragonal zircon structure as well as their mixture dependently on Eu and Ca concentrations. Characterization of the samples morphology made using scanning electron microscope Tescan Mira 3 LMU with 1 nm electronic beam diameter have shown that each sample consist of nanoparticles of the same diameters, but these diameters are varied from 20 nm to 100 nm for different samples. The Ca-undoped samples are characterized by the largest 100 nm diameters of nanoparticles. Luminescence properties also depend on concentrations and excitation wave length as well. Two types of Eu3+ centers were found by emission spectra. Structures of these centers are discussed taking into account crystal structure, possible Ca-induced defects and surface effects.
Authors : Jeppe Damkjær Christiansen; Jacques Chevallier; Brin Julsgaard;
Affiliations : Department of Physics and Astronomy, Aarhus University; Department of Physics and Astronomy, Aarhus University; Department of Physics and Astronomy, Aarhus University and Interdisciplinary Nanoscience Center, Aarhus University.
Resume : The efficiency of modern photovoltaic units are approaching the SQ-limit, that is, the maximum obtainable efficiency. Thus, new methods are in demand, to increase this limit in the process towards a renewable energy-system. Upconversion, the process of combining several low energy photons to one photon of higher, is a promising way achieving this goal. Trivalent rare-earth ions, and especially erbium ions, have proven to be a promising candidate for upconversion. We investigate erbium based upconversion form coatings produced by magnetrun sputtering. The coating consists of erbium doped TiO2 placed on a substrate of fused quartz. The aim of this work is to construct a model for the upconversion dynamics based on rate equations. As far as possible, the parameters of the model is experimentally determined. The main parameters of the model are the absorption cross-section of the erbium ions, and the different transition rates governing population decay and increase. The absorption cross-section is determined through absorption spectra using a spectrophotometer and by measurements of the complex index-of-refraction obtained with an ellipsometer. From the ground-state-absorption cross-section combined with the theories of McCumber, and Judd & Ofelt it is possible to compute the exited-state cross-sections as well. The transition rates will be determined through the exited-state lifetime of the erbium ions, measured from time-resolved-luminescence experiments. Besides enabling investigation of the upconversion dynamics the model paves the way for a direct investigation of transition rates such as multi-phonon relaxation and Förster-resonance energy-transfer.
Authors : Alexandra Madeira,Mona Tréguer-Delapierre,Irene Goldthorpe,Laurent Servant
Affiliations : Alexandra Madeira - ICMCB, 87 Avenue du Dr Albert Schweitzer, 33600 Pessac; Mona Tréguer-Delapierre - ICMCB, 87 Avenue du Dr Albert Schweitzer, 33600 Pessac; Irene Goldthorpe - Department of Electrical and Computer Engineering, University of Waterloo, 200 University Avenue West Waterloo, Ontario, N2L 3G1 Canada; Laurent Servant - ISM, 351 Cours de la Libération, 33405 Talence Cedex
Resume : Transparent electrodes are used in a variety of optoelectrical devices including solar cells, flat panel displays, touch screens and transparent heaters. Indium tin oxide is the most commonly used transparent electrode material, however, the need for material cost reduction, mechanical flexibility and low cost/temperature fabrication techniques have recently oriented research toward alternative materials. Among them, random networks of solution-synthesized silver nanowires present optical and electrical properties approaching those of ITO, while being much more flexible and inexpensive. As with all transparent electrode materials, the conductivity should be maximized for a given transparency. In this work, the strategy to achieve this is to employ two novel silver nanostructures: ultra-long nanowires and branched nanowires. Both these nanostructures reduce the number of high resistance junctions in the nanowire network and thus lower the overall sheet resistance of the electrode. We will show how these nanostructures can be produced in colloidal suspension, how they grow and what impact they have on the electrode properties.
Authors : Norio Saito(1,2,3), Pierric Lemoined(4), Stéphane Cordier(4), Takeo Ohsawa(1,3), Fabien Grasset(1,3,5), Yoshiki Wada(1), Jeffrey S. Cross(2), Naoki Ohashi(1,3,5)
Affiliations : (1) NIMS, Japan ; (2) Tokyo Institute of Technology, Japan; (3) NIMS-Saint-Gobain Center of Excellence for Advanced Materials, NIMS, Japan; (4) UMR 6226, University of Rennes 1, France; (5) UMI 3629, NIMS, Japan
Resume : Molybdenum-cluster-halide complex, expressed by [Mo6X8Z6] (X, Z=halogen), is regarded as a building block for construction of nanostructures hybridizing inorganic complex and organic molecules. Hybridization of organic and inorganic components is a new trends in materials science, as perovskite-type lead halide based compounds including organic molecular ion in their crystal lattice is regarded as a promising new functional material for photovoltaic applications. In this study, we have devoted ourselves to investigate functions of the [Mo6X8Z6]-complex on exploration study aiming to find new functionality in nanostructured materials. In particular, we have investigated the effect of ion exchange for halogens represented by X and Y in [Mo6X8Z6] from both chemical experiments and DFT simulations. As a result, we found that such ion exchange achieves drastic modification of the optical properties of the [Mo6X8Z6]-based complex compounds.
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Nanobiomaterials : Yogendra Mishra, Ion Tiginyanu
Authors : Mady Elbahri
Affiliations : Nanochemistry and nanoengineering, Department of Chemistry and Materials Science, Aalto University, Helsinki, Finland
Resume : The dynamic underwater chemistry seen in nature is inspiring for the next generation of sustainable chemistry. This talk discusses the Leidenfrost dynamic chemistry occurring in an underwater overheated confined zone as a new tool for customized creation of nanoclusters of zinc peroxide. Also, the cytotoxicity of such nanoclusters on cancer cells is demonstrated. The Leidenfrost driven swimming enables physical separation between the nucleation and growth events, hence governs a new synthetic route to formation of monodisperse and size tailored nanoparticles whose size is proportional to the concentration of reagents in the solution. Peroxides act as a supplier of oxygen, hence have therapeutic uses against complex diseases, including cancer.
Authors : I. Latini1,2, C. Berlangieri1,2, E. Carretti1,2, L. Dei1,2 , S. Scarano1, and M. Minunni1,2
Affiliations : 1Laboratorio Sensori e Biosensori, Dipartimento di Chimica ?Ugo Schiff?, Università degli Studi di Firenze, via della Lastruccia 3-13, Sesto Fiorentino, 50019, Firenze, Italy. 2Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase, CSGI - Dipartimento di Chimica, Università degli Studi di Firenze, via della Lastruccia 3-13, Sesto Fiorentino, 50019, Firenze, Italy.
Resume : Label free and real time optical transduction, in particular by Surface Plasmon Resonance (SPR), is undoubtedly at the forefront of affinity-based biosensing (1) thanks to its sensitivity, specificity, versatility, miniaturization perspectives, reusability, and low cost. Despite its application to a broad area of interests, from environment to food analysis, from drug discovery to diagnostics, their exploitation in cultural heritage conservation is still unexplored. First a biosensor containing as specific biomarkers, ovalbumin (OVA) and immunoglobulin Y (IgY) has been set up for egg white and yolk recognition, respectively. This analytical method is here coupled for the first time to some innovative Water-based Highly Viscous Polymeric Dispersions (HVPD) composed by polyvinyl acetate (PVA), borax, and water, recently developed and successfully exploited for the selective removal of protein materials from painted surfaces of historical and artistic interest (2). This SPR biosensor allows the simultaneous recognition of albumen and/or yolk in HVPD extracts. Moreover, other SPR-based approaches based on LSPR phenomenon specifically tailored for the selective recognition of OVA and based on Au nanoparticles (AuNPs) embedded in a polydopanmine matrix have been prepared and tested. Finally, a combined 'clean & check' approach was optimized, consisting in the HVPD application on simulated and real art samples followed by the evaluation of the presence in the extract of egg components. The method is mini-invasive and fast, allowing also the further identification of other protein matrices possibly present in the HVPD extract (3,4).  M.L. Ermini, S. Mariani, S. Scarano, M. Minunni, Biosensors and Bioelectronics 61 (2014) 28-37.  I. Natali, E. Carretti, L. Angelova, P. Baglioni, R.G. Weiss, L. Dei, Langmuir 27 (2011) 13226?13235.  S. Scarano, E. Carretti, L. Dei, P. Baglioni, M. Minunni, Biosensors and Bioelectronics 85 (2016) 83-89.  S. Scarano, C. Berlangieri, E. Carretti, L. Dei, M. Minunni, Microchimica Acta, in press
Authors : Sawsan Almohammed,a,b James H. Ric, a and Brian J. Rodriguez ,a,b
Affiliations : a. School of Physics, University College Dublin, Belfield, Dublin 4, Ireland b. Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
Resume : Self-assembled diphenylalanine (FF) peptide nanotubes (PNTs) have attracted significant attention due to their well-ordered supramolecular structure and wide range of functional capabilities that may enable potential nanobiotechnology applications. However, self-assembled PNTs are generally inhomogenous at the macroscale, which has limited their potential use. Reproducibly controlling the assembly and alignment of PNTs is therefore critical to enable the widespread use of PNTs, e.g., in sensing applications. In this study, a surface patterning technique based on UV/ozone exposure through a shadow mask is used to align PNTs (Fig. 1a). Exposed regions become hydrophilic, leading to directed spreading of the FF solution and alignment of the PNTs that improves as the difference in wettability between adjacent regions increases. Alignment was further found to depend on the concentration- and temperature-dependent diameter of the PNTs formed and the size of the hydrophilic area. Having optimized the alignment of the PNTs (Fig.1b), they are coated with silver nanoparticles and the device is used to sense an analyte molecule using surface enhanced Raman spectroscopy (example shown in Fig. 1c) sensing the presence of a porphyrin TMPyP analyte at concentrations down to 10-14 mol, which indicates single molecule detection (shown in Fig. 1d). Bio-template based on PNTs+Ag NPs nanocomposites is found to be reactive under UV lamp illumination, since PNTs have large band gaps ~4.9 ev, charge transfer can occur when stimulating by visible light. Herein, we also show significant increase in Raman signal using three different probe molecule TMPyP, RB, and 4ABT when the bio-template exposure to UV light for approximately 35 to 40 minutes. The increase in Raman intensity and the fluctuation observed in this study can be due to charge transfer mechanism between the nanotubes and the nanoparticles.
Authors : Andrei POSTNIKOV (1), Kamil MOLDOSANOV (2)
Affiliations : (1) Université de Lorraine, LCP-A2MC, 1 Bd Arago, F-57078 Metz, France ; (2) Kyrgyz-Russian Slavic University, 44 Kiyevskaya St., Bishkek 720000, Kyrgyzstan
Resume : The interplay of size confinement effects and physical characteristics (positions of maxima in the spectrum of longitudinal acoustic vibration modes, the density of electronic states at the Fermi level) in gold nano-objects may enable special tuning of absorption / emission characteristics in different wavelength ranges, depending on the nano-objects’ shape. Earlier we outlined a design for THz generation in gold nano-objects via phonon-assisted absorption of microwaves (mw) . Our present calculations support a setup for the generation of soft terahertz radiation ([nu] ≈ 0.1–0.5 THz), again by metallic nano-objects exposed to mw; however, in difference from the earlier outlined scheme, the present mechanism anticipates an involvement of two longitudinal acoustic phonons with opposite wavevector directions, whose energy difference would equal h[nu]. The excited Fermi electron then relaxes releasing a THz photon at frequency [nu]. The selectivity in the phonon absorption can be enhanced by tuning the shape of nano-object; in particular, the cases of gold nanobars, nanorings, and nano-cubooctahedra are analysed. The specificty of the suggested THz source would be its broad aperture, that may enable its use e.g. in security control. Otherwise a low-frequency THz source could find its use in biomedical screening, due to known contrast of cancer cells to sane bio tissue in the THz range.  K. Moldosanov and A. Postnikov, Beilstein J. of Nanotechnology 7, 983 (2016); DOI:10.3762/bjnano.7.90
Authors : Jagriti Narang 1*, Chaitali Singhal 1#, Ashish Mathur 1, Ashwani Kumar Dubey 2, C.S. Pundir 3
Affiliations : 1 Amity Institute of Nanotechnology, Amity University, Noida, 201301, India 2 Amity School of Engineering and Technology, Amity University, Noida, 201301, (UP) 3 Department of Biochemistry, Maharishi Dayanand University, Rohtak, (Haryana), India *Corresponding Author # Presenting Author Dr. Jagriti Narang Ms. Chaitali Singhal Amity University, Noida, India Amity University, Noida, India Phone num.: 9811792572 Phone num.: 9717717446 Email: firstname.lastname@example.org Email: email@example.com
Resume : We have developed various platforms for detection of the date-rape drug, ketamine, in beverages like whiskey, rum and pepsi. The present work shows the comparison of the electrochemical sensing and colorimetric detection of ketamine. Firstly, platinum-palladium (Pt-Pd) nanoalloys were used as the sensing platform on fluorine doped tin oxide (FTO) electrode for electrochemical sensing of ketmine. This was done on a 3-electrode system with Ag/AgCl as the reference electrode, platinum wire as the counter electrode and Pt-Pd/FTO as the working electrode. Secondly, Graphene Oxide-Zeolite (GO-Zeo) nanocomposites were synthesized and used for sensing of ketamine on electrochemical microfluidic paper based analytical device (EµPAD). The use of paper based device makes the work highly economic in comparison to the expensive metal electrodes. This paper based device was used as a two electrode system for electrochemical sensing of ketamine. Finally, the cost of the detection was further reduced by preparing a naked eye colorimetric sensor for detection of ketamine. The change in color of the paper strip upon addition of the analyte is the basis of sensing. The developed paper strip was linked with a smart phone app which automatically detects the color change and sends message to the selected numbers when drink is not safe, if needed.
Authors : Ghulam Jalani
Affiliations : Dalhousie University
Resume : Localized and recurring delivery of drugs in the hour of need is of great importance in many clinical conditions such as in the treatment of solid tumors, post surgical wounds and localized infections. This helps increase the drug efficacy and minimize the side effects of anesthetics. Lanthanide-doped upconverting nanoparticles (UCNPs) have emerged as excellent nanotransducers for converting longer wavelength near-infrared (NIR) light to shorter wavelengths spanning the ultraviolet (UV) to the visible (Vis) regions of the spectrum via a multiphoton absorption process, known as upconversion. We have developed a new phototriggered drug delivery system consisting of LiYF4:Yb3 /Tm3 @SiO2 NIR to UV–Vis–NIR UCNPs individually coated with a 10 ± 2 nm layer of chitosan (CH) hydrogel cross-linked with a photocleavable cross-linker (PhL). We encapsulated fluorescent-bovine serum albumin (FITC-BSA) inside the gel. Under 980 nm excitation, the upconverted UV emission cleaves the PhL cross-links and instantaneously liberates the FITC-BSA under 2 cm thick tissue. The release is immediately arrested if the excitation source is switched off. The upconverted NIR light allows for the tracking of particles under the tissue. Nucleus pulposus (NP) cells cultured with UCNPs are viable both in the presence and in the absence of laser irradiation. Controlled drug delivery of large biomolecules and deep tissue imaging make this system an excellent theranostic platform for tissue engineering, biomapping, and cellular imaging applications.
Authors : J. Gröttrup,1 D. Smazna,1 S. Shree, 1 I. Hölken,1 I. Paulowicz,1 S. Kaps,1 O. Lupan,1,2 T. Monteiro,3 Ion Tiginyanu,2 Lorenz Kienle,1 Rainer Adelung1 , Y. K. Mishra1
Affiliations : 1Institute for Materials Science, Kiel University, Kaiserstr. 2, D-24143, Kiel, Germany 2Technical University of Moldova, 168 Stefan cel Mare Av., MD-2004 Chisinau, Republic of Moldova 3Department of Physics and I3N, Institute for Nanostructures, Nanomodelling and Nanofabrication, University of Aveiro, Aveiro, Portugal
Resume : The flame based approach offers unique opportunities for metal oxide nanostructuring, ranging from Q1D nanowires to large 3D interconnected networks. This strategy offers direct integration of ZnO structures and their networks on the desired substrates for various applications, e.g., whispering gallery modes, photocatalysis or nanosensing (UV/gases) applications.[1-4] The flame grown ZnO tetrapods and nano- and microstructures exhibit very low cytotoxicity and have shown strong potentials against antiviral applications. The unique 3D shape of the ZnO tetrapods facilitates them to be used as efficient fillers for advanced composites, e.g., self-reporting composites and many others. The 3D porous, flexible and conducting network from ceramic materials are now-a-days very important because of their technological relevance and the developed flame method offers desired synthesis of various ZnO and SnO2 networks. These 3D porous networks can be decorated with other nanostructures for designing hybrid multifunctional materials and can also be used as sacrificial templates to grow new nanomaterials and composites. Refs: Part. Part. Syst. Charact. 30, 2013, 775-783;  ACS Appl. Mater. Interfaces 6, 2014, 7806−7815;  ACS Appl. Mater. Interfaces 7, 2015, 14303–14316; Adv. Mater. 26, 2014, 1541-1550; J. Immunol. 196, 2016, 4566-4575;  Adv. Mater. 26, 2014, 1342-1347;  Adv. Funct. 27, 2017, 1604676; Adv. Mater. 24, 2012, 3486-3490.
Nanosensing : Yogendra Mishra, Jost Adam
Authors : Jan Linnros, Miao Zhang and Ilya Sychugov
Affiliations : Dept of Applied Physics, Royal Institute of Technology, Electrum 229, 16440 Kista-Stockholm, Sweden
Resume : Solid state nanopores have recently attracted a large interest for detection of single molecules and as a possible method for DNA sequencing. The nanopores of a few nanometer dimensions are usually fabricated in a nitride membrane using electron beam drilling. The translocation of DNA strands (or proteins) is then detected by the blockade of the nanopore resulting in a drop of the ionic current between the two reservoirs on opposing sides of the membrane. This technology is, however, difficult to scale up and as an alternative, optical techniques can be used in combination with arrays of nanopores for massive, parallel readout. This requires labelling of biomolecules or nucleotides, by fluorophores which can readily be read out by a CCD or CMOS camera. We have developed a technique for fabricating arrays of nanopores in a silicon membrane reaching diameters down to ~10 nm. The fabrication scheme involves optical lithography and ICP etching from the backside of an SOI wafer to etch out membranes of a few hundreds micrometer diameter. The silicon device layer at the front is then patterned using e-beam or optical lithography followed by anisotropic KOH etching to form inverted pyramids which serve as etch pits to initiate pore formation in a subsequent electrochemical etching step. In this presentation, I will review the fabrication techniques to achieve nanopore arrays and our initial DNA translocation experiments through the nanopore arrays using fluorophore labelled DNA strands. It will also be demonstrated that the DNA translocation is affected by a thermophoretic effect caused by heating from the excitation laser beam spot.
Authors : Kwang-Hee Lee, Dong-Seok Leem, Gae Hwang Lee, Sungyoung Yun, Kyung-Bae Park, Yeong Suk Choi, Yong Wan Jin, Sunghan Kim
Affiliations : Materials Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, Republic of Korea 16678
Resume : The conventional CMOS image sensor based on silicon photodetectors has been the efficient route for the fabrication of high performance mobile phone cameras, but this technology now suffers from resolution limitation due to the broad absorption spectrum of Si in the visible region and its low coefficient of absorption. The use of organic materials led to a reduction of the optical and electrical crosstalks, and also to the possible reduction of spectral crosstalk by modifying the molecular structure for better absorption at specific wavelengths. Among acceptors, fullerene derivatives has been the preferred material due to its high electron mobility and its good miscibility. However, the broad absorption spectrum of C60 with a peak intensity in the blue region is a drawback for the performance of green-sensitive organic photodetector (OPD). Therefore, the development of a nonfullerene semiconducting material with specific color absorption and high carrier mobility is required to improve the OPDs for application as CMOS image sensors. In this study, a new n-type small molecule with green-selective absorption was designed using by molecular structure calculation using Gaussian 09 and synthesized, which is comprising of an indacenodithiophene as the fused backbone and two dicyanovinylene at both extremities. As the promising candidate of acceptor material, this material can be adopted for the green-sensitive OPD in CMOS image sensor with high spectral sensitivity. As the promising candidate of acceptor material, this material can be adopted for the green-sensitive OPD in CMOS image sensor with high spectral sensitivity.
Authors : Julian Rechmann, Alissa C. Götzinger, Elena Dirksen, Maciej Krzywiecki, Asif Bashir, Thomas J. J. Müller, and Andreas Erbe
Affiliations : Julian Rechmann; Andreas Erbe; Max-Plank-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, 40237 Düsseldorf, Germany Alissa C. Götzinger; Elena Dirksen; Thomas J. J. Müller; Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany Maciej Krzywiecki; Silesian University of Technology, Konarskiego 22B, 44-100 Gliwice, Poland Andreas Erbe; NTNU, Norwegian University of Science and Technology, 7491 Trondheim, Norway
Resume : Electronic properties of inorganic compound semiconductors, such as oxides and nitrides, are largely governed by the fixed native defect chemistry of a respective system. Organic molecules, on the other hand, provide a much simpler means to systematically alter energy level alignment at the interface. To study the effect of such modifications, bare polycrystalline Au(111) surfaces were functionalized with phenothiazine based SAMs. Phenothiazines are a class of redox-active, fluorescent molecules, exhibiting p-type semiconducting character. Due to its ability to form dense and well-ordered monolayers as well as its large π-electron system, energy levels should couple with bands of metals/semiconductors. X-ray photoelectron and photoemission yield spectroscopy (XPS and PYS, respectively) have been used to measure the alignment of the frontier orbitals, which correspond to valence and conduction band, with respect to the Fermi level of the system, and the vacuum level of the metal and in the SAMs. The electronic structure was then correlated to the electrochemical properties of the system around the open circuit potential in an acidic, a neutral and an alkaline electrolyte. Electrochemical measurements were performed by linear sweep voltammetry (LSV). As a result, a correlation matrix was obtained, showing the effect of interfacial electronic structure, via the alignment of the frontier orbitals and the work function, on steady state electrochemical quantities.
Authors : Sreetosh Goswami, Adam J. Matula, Santi P. Rath, Svante Hedstrom, Surajit Saha, Meenakshi Annamalai, Debabrata Sengupta, Abhijeet Patra, Siddhartha Ghosh, Hariom Jani, Soumya Sarkar, Mallikarjuna Rao Motapothula, Christian A. Nijhuis, Jens Martin, Sreebrata Goswami, Victor S. Batista, T. Venkatesan
Affiliations : National University of Singapore; Yale University; Indian Association for the Cultivation of Science; Yale University; National University of Singapore; National University of Singapore; Indian Association for the Cultivation of Science; National University of Singapore; National University of Singapore; National University of Singapore; National University of Singapore; National University of Singapore; National University of Singapore; National University of Singapore; Indian Association for the Cultivation of Science; Yale University; National University of Singapore
Resume : Resistive memory devices can be broadly defined as electrical switches that retain a state of internal resistance based on the history of applied voltage. Such devices hold several performance characteristics that can potentially exceed conventional integrated circuit technology and are projected to be the building blocks of the next generation of computing architectures such as neuromorphic computing. While some oxide resistive memory devices are well characterized and slated for commercial applications, other genres, especially organic resistive memories are quite far off from the benchmarks. The challenges include insufficient consistency, endurance, retention, switching speed and a lack of understanding of the operating device mechanisms. In this report, we demonstrate a resistive memory device with a spin-coated active layer of transition metal complex sandwiched between two metal electrodes with reproducibility over 300 devices. We overcome the large read-write voltage and speed limitations of such devices by using nanoparticles on the bottom electrode. This brings the switching voltage down to 500mV and reduces the device resistance by almost 4 orders enabling switching in 30ns. With 100ns pulses we observe endurance of more than 10^11 cycles without degradation along with a stability of more than 10^6s. Insight into the molecular switching mechanism of the device is obtained via in situ Raman-spectroscopy in conjunction with UV-Vis spectroscopy and spectroelectrochemistry (supported by Density Functional Theory (DFT)). These allow the determination of the molecular electronic states at each conductance level and substantiate that the redox state of the ligands determines the switching states of the device. Both in terms of device performance and understanding this study presents a significant leap in organic resistive memory technology.
Authors : Tianying Sun, Feng Wang
Affiliations : Department of Physics and Materials Science, City University of Hong Kong
Resume : Production and sale of fraudulent goods have become a global epidemic, posing major threats to individual consumers and causing enormous financial damages. Considerable efforts have been devoted to designing anti-counterfeiting measures, leading to many different anti-counterfeiting technologies on the current market. However, traditional methods such as barcoding and water marking are not very effective, because these techniques are outdated and easy to be duplicated. We describe a novel strategy for creating anti-counterfeiting patterns by taking advantage of highly tunable lanthanide luminescence. Instead of using multicolor taggants that are responsive to a single-wavelength excitation, we use luminescent nanotaggants that are encrypted to be excited with distinct wavelengths. Decryption is achieved by examining the temporal color response of the pattern to different illuminations. A genuine pattern is guaranteed only if the desired luminescent color sequence is achieved. By spatial partition of different nanotaggants via a serial contact printing process, we further demonstrate that spatially encoded graphics can also be encrypted as anti-counterfeiting patterns. We believe that the encryption technique described here can substantially increase the difficulty of duplication and thus to provide extra high-level security protection in many business applications.
Authors : Chung-Hyeon Ryu1, Hyun-Dong Kim1, and Hak-Sung Kim1, 2*
Affiliations : 1 Department of Mechanical Engineering, Hanyang University, Haengdang-dong, Seongdong-gu, Seoul 166-791, South Korea 2 Institute of Nano Science and Technology, Hanyang University, Seoul, 133-791, Korea
Resume : In this study, the rheological behavior of Cu nano-inks with various wt% of polymer binder was investigated during the flash light sintering process. The rheological behavior of Cu nano-inks was measured using a rheometer system to analyze the influence of rheological factor such as viscosity and thixotropic index. Fabricated Cu nano-inks were printed on polyimide substrate using a screen printing method. Also, the effect of screen printing speed to printability was investigated. To sinter the printed Cu nano-inks, flash light irradiation system was employed. The flash light irradiation conditions (pulse power, pulse number, on-time, and off-time) were optimized to obtain the high sintering characterization of Cu nano-inks. In order to characterize the microstructures and transformation crystal phase of the sintered Cu nano-inks, scanning electron microscopy (SEM) and x-ray diffraction (XRD) were performed. The resistivity of sintered Cu nano-inks was calculated using the four-point probe method and alpha step. From the results, the optimal printed and sintered Cu nano-inks had a 7.56 μΩcm resistivity and 5B level of adhesion strength without substrate warpage. Acknowledgments This work was supported by a National Research Foundation of Korea (NRF), funded by the Ministry of Education (2015R1D1A1A09058418).
Authors : Soumya Sarkar, Surajit Saha, M.R. Motapothula, B.C. Cao, Abhijeet Patra, Saurav Prakash, Siddhartha Ghosh, Yu Ting, T. Venkatesan
Affiliations : NUS Graduate School for Integrative Sciences and Engineering; NUS Nanoscience and Nanotechnology Institute; NUS Nanoscience and Nanotechnology Institute; Nanyang Technological University; NUS Nanoscience and Nanotechnology Institute;NUS Graduate School for Integrative Sciences and Engineering; NUS Nanoscience and Nanotechnology Institute; Nanyang Technological University; National University of Singapore
Resume : Strongly correlated electronic systems such as Transition Metal Oxides often possess various mid-gap states originating from intrinsic defects in these materials. In this work, we investigate an extremely sharp and strong Photoluminescence (PL) transition originating from such defect states in two widely used perovskites, LaAlO3 and SrTiO3, in the NIR energy range. A detailed study of the PL as a function of temperature and magnetic field has been conducted to understand the behavior and origin of the transition involved. The temperature dependence of the PL peak position for SrTiO3 is observed to be opposite to that in LaAlO3. Our results reveal the presence of a spin/orbital character in these transitions which is evident from the splitting of these defect energy levels under a high magnetic field. These PL transitions have the potential for enabling non-contact thermal and field sensors, and advanced photonic devices for lasing applications. Ref: Sarkar, S. et al. Sci. Rep. 6, 33145; doi: 10.1038/srep33145 (2016)
Optoelectronic Materials : Jost Adam, Oliver Schmidt
Authors : Nimai Mishra, Liberato Manna, Jennifer Hollingsworth, and Chan Yinthai
Affiliations : Department of Nanochemistry , Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
Resume : While conventional spherical colloidal nanocrystals have shown promise in these fields due to their ease of fabrication, processibility and salient optical properties, it may be envisaged that more applications may emerge if nanocrystals can be synthesized in shapes of higher complexity and therefore increased functionality. Here we will presents a systematic, surfactant-driven hot injection method to synthesize CdSe seeded CdS nanoheterostructures with very high yield. This was extended to other systems such as CdSe/CdTe and CdTe/CdS or PbSe/PbS and Ag2Se/Ag2S via cation exchange techniques. In order to elucidate the reactivity of the facets at the tips of such branched structures as a function of the shape of the arms, we exposed the structures of various arm dimensions to controlled amounts of metal precursors and discovered conditions in which the metal nanoparticle can be deposited precisely at the tip of one of four arms with symmetric reactivity. Afterward, we utilize these particles to overcome some of the key problems in the assembly of anisotropic shaped nanoparticles. In next, we will showcase the utility of such branched heterostructures in applications such as light-emitting diodes and solar cells. CdSe/CdTe tetrapods immobilized on oleylamine-functionalized reduced graphene oxide (rGO) sheets can be homogeneously mixed with an organic dye (PCDTBT) to form donor?acceptor dispersed heterojunctions and exhibit a high power conversion efficiency of ? 3.3% in solar cell devices. At the end we will discuss a single active layer quantum dot light-emitting diode device based on colloidal CdSe (core)/CdS (arm) tetrapod nanostructures capable of simultaneously producing room temperature electroluminesence (EL) peaks at two spectrally distinct wavelengths, namely, at?500 and?660 nm.
Authors : Seckin Akin1,2,*, Numan Eczacioglu3, Begum Terzi3, Yakup Ulusu3, Ozlem Ates Sonmezoglu3, Savas Sonmezoglu1,2
Affiliations : 1Department of Metallurgical & Materials Engineering, Karamanoglu Mehmetbey University, Karaman, Turkey 2Nanotechnology R&D Laboratory, Karamanoglu Mehmetbey University, Karaman, Turkey 3Department of Bioengineering, Karamanoglu Mehmetbey University, Karaman, Turkey *e-mail: firstname.lastname@example.org
Resume : As has been the case for past years, the key challenge in the commercialization of dye-sensitized solar cells (DSSCs) is the poor charge transfer and high recombination rate in device architecture [1,2]. Herein, a novel approach based on high-yield DNA molecules in different structure (eukaryotic / prokaryotic) and shape (circular / linear) has been proposed as not only linker bridging unit in the photosensitization process but also thin tunneling barrier at TiO2/dye/electrolyte interfaces. As compared to bare TiO2, this modification provides a large steric hindrance which plays a role in blocking recombination by preventing the access of electrons to the redox electrolyte as well as facilitates an efficient electron harvesting by introducing alternative anchoring facilities and/or serving as a photon cage. By immobilizing linear shaped genomic DNA molecules in eukaryotic structure, the efficiency has been dramatically enhanced to 8.74% by improving the Voc from 688 to 709 mV, with synergistical Jsc enhancement from 14.51 to 17.88 mA.cm?2. Furthermore, time-resolved fluorescence spectroscopy reveals improved an electron transfer rate whereas electrochemical analysis indicates a reduced charge transport resistance (Rct = 17.29 to 4.08 ?). Finally, we could also demonstrate good stability of the devices under prolonged irradiation. These findings suggest that bio-functionalization by engineering of the photoelectrode can be a novel guideline toward facile passivating mechanisms and high e?ciencies. References  Ates Sonmezoglu O., Akin S., Terzi B., Mutlu S., Sonmezoglu S., Adv. Funct. Mater., 2016, 26, 8776?8783.  Akin S., Gulen M., Sayin S., Azak H., Yildiz H. B., Sonmezoglu S., J. Power Sources, 2016, 307, 796?805.
Authors : Mahir GULEN1,2*, Erdinc EROL1,2, Seckin AKIN1,2 and Savas SONMEZOGLU1,2
Affiliations : 1Department of Metallurgical and Materials Engineering, Faculty of Engineering, Karamanoğlu Mehmetbey University, 70200, Karaman, Turkey 2Nanotechnology R&D Laboratory, Karamanoğlu Mehmetbey University, 70200, Karaman, Turkey
Resume : In the current work, for the first time, Cu2XSnS4 (X = Co and Fe) thin films have been directly electrodeposited on the substrates following with sulfurization process at 5000C for 45 min and these thin films were employed as counter electrodes (CEs) in dye sensitized solar cell (DSSC). The physical and electrochemical properties of the thin films were investigated by pertinent measurements. The obtained results exhibited that the kesterite structures with Co and Fe have been successfully built up with the proposed method. Moreover, the introduction of Co into kesterite structure enhances the crystallite structures, narrows crystallite size and enlarges the surface area of the film in comparison with that of Fe due to smaller ionic radius of Co2+. Furthermore, the Cu2CoSnS4 CE demonstrated a higher electrocatalytic activity than that of Cu2FeSnS4, offering a higher efficiency (ɳ) of 5.55%, prolonged electron lifetime, better multiple start/stop capability with no decrement in Jsc after 10 cycles and a higher Jsc stability under sustained irradiation compare to Cu2FeSnS4 based cell (ɳ = 5.14%). These can be ascribed to larger surface area of Cu2CoSnS4 which improves diffusion ability and interaction of electrolyte with CE, higher conductivity and stronger adherence of Cu2CoSnS4 on the substrate which results in lower serial and charge transfer resistances at the interfaces of CE/electrolyte and CE/substrate. Therefore, these CZTS derivatives can be offered as alternatives to high-cost platinum for robust and low-cost DSSC applications due to their excellent catalytic activities, highly stabilities, and simple fabrication processes and low-costs. Acknowledgement–This study was supported by the European Union through the COST Action MP1407 “Electrochemical processing methodologies and corrosion protection for device and systems miniaturization (e-MINDS)”, and by the Scientific and Technological Research Council of Turkey (TUBITAK Grant Number 115M762) who provided financial support for this research.
Authors : Djadidi TOYBOU[1,2], Caroline CELLE, Laurent CHARLET, Jean-Pierre SIMONATO
Affiliations : Univ. Grenoble Alpes, CEA, LITEN/DTNM, F-38054 Grenoble, France ; Univ. Grenoble Alpes, CNRS, ISTerre, Grenoble, France
Resume : Transparent conductive films are widely used in common optoelectronics devices like organics photovoltaics, displays and transparent heaters. The fabrication of transparent conductive films is currently realized with thin films of transparent conductive oxides, and in particular indium tin oxide (ITO). The as-made ITO transparent conductors lead the market with outstanding optoelectronics performances (R/sq >50 ohm/sq and T >90%) but suffer from limitations like costly fabrication process and brittleness under mechanical stresses. The existing market is evolving towards new types of devices, low cost, high-performance and flexible. Candidate replacement materials for ITO include carbon nanotube networks (CNT), graphene thin films, conductive polymers, metallic grids and metal nanowire networks. Metal nanowires appear the most promising alternative. In particular, silver nanowire networks offer flexible transparent electrodes with similar performances to ITO and less fabrication cost, above all a simple and controlled way of synthesis. Thanks to polyol process, we developed synthesis method able to cover a large spectrum of length/diameter combination. That exploit have been performed by means of varying length and diameter in independent way. This, lead to cover a wide range of applications that require specific optoelectronics properties. We will present our synthesis method for several nanowire morphologies and associated optoelectronic performances. Possible integration according to each morphology/performances will be also discussed.
Authors : Wan-Ho Chung1, Yong-Rae Jang1, Yeon-Taek Hwang1 and Hak-Sung Kim1, 2*
Affiliations : 1 Department of Mechanical Engineering, Hanyang University, 17 Haendang-Dong, Seongdong-Gu, Seoul 133-791 Korea, 2 Institute of Nano Science and Technology, Hanyang University, Seoul, 133-791, Korea, Fax: 82-(2)-2220-2299 E-mail address: email@example.com
Resume : In this work, the change of silver nanowire during the combined flash light welding process with UV and NIR light was investigated. The coated silver nanowire on a PET substrate using bar-coater were welded at room temperature, and under ambient conditions by combined flash light irradiation. To monitor the changing silver nanowire for the combined flash light welding process, in-situ monitoring system with electrical circuit using Wheatstone bridge was devised and the sheet resistance changes of silver nanowire during the welding process were recorded using oscilloscope under various flash light conditions (e.g. light energy, on- and off-time duration, and pulse numbers) with UV and NIR irradiation. The microstructure of the welded silver nanowire film and the interface between the silver nanowire film and PET substrate were observed using a scanning electron microscope. Using the devised in-situ monitoring system, the combined flash light welding mechanism of silver nanowire was studied (e.g. the evaporation of organic binder around silver nanowire, the welding form of silver nanowires, etc.). The optimized flash light welding process produces a silver nanowire film with a lower sheet resistance (45.2 ohm/sq) and high transparency (93.46 %) without damaging the PET substrate. Acknowledgments This work was supported by a National Research Foundation of Korea (NRF), funded by the Ministry of Education (2015R1D1A1A09058418)
Nanomaterials for Energy : Jost Adam
Authors : D. K. Avasthi1, M. Bala 2, Anuradha Verma3, K.K. Jana4, P. Maiti4, Sahab Dass3, S.K. Triapthi5 and K. Asokan6
Affiliations : 1Amity Institute of Nanotechnology, Amity University, Noida-201313 2Department of Physics, Delhi University, Delhi 3Department of Chemistry, Dayalbagh Engineering Institute, Agra 4School of Materials Science, Indian Institute of Technology, Varanasi 5Department of Physics, Panjab University, Chandigarh-160014 6Inter University Accelerator Centre, New Delhi-110067
Resume : The nanostructures are of great interest in context with the materials for energy due to their unique electronic and optical properties. The role of nanostructures in various types of materials of energy, e.g., thermoelectric materials [1-3], fuel cell [4,5] having nanometric size pores, materials for photo splitting of water [6,7], photo catalytic action  and thermal storage , have attracted attention of researchers. Ion irradiation due to their unique property of depositing large energy density in localized region  has been exploited in creating nanostructures and engineering the materials for energy. Some of our ongoing research in area of materials for energy in collaboration with other institutions is briefed here. References 1. J.F. Lee et al., NPG Asia Materials (2010) 2, 152–158. 2. M. Bala, C. Pannu, S. Gupta, T.S. Tripathi, S.K. Tripathi, K. Asokan, D.K. Avasthi, Phys. Chem. Chem. Phys. 17(2015)24427, 3. M. Bala, S. Gupta, S. Tripathi, S. Verma, S.K. Tripathi, K. Asokan, D.K. Avasthi, RSC Advances 5 (2015) 25887. 4. C.Wang et al., Nano Letters 4(2004)345, 5. K. K. Jana, A. Srivastava, Om Prakash, D.K. Avasthi, D. Rana, V.K. Shahi, P. Maiti, Jl. Of Power Sources 301(2016)338. 6. S. Hoang et al., J. Am. Chem. Soc. 2012, 134, 3659−3662, 7. Anuradha Verma, Anupam Srivastav, Anamika Banerjee, Dipika Sharma, Shailja Sharma, Udai Bhan Singh, Vibha Rani Satsangi, Rohit Shrivastav, Devesh Kumar Avasthi, Sahab Dass, Journal of Power Sources 315(2016)152-160. 8. Z. Jiang et al., J. Mater. Chem. A 2 (2014) 19861. 9. Avasthi, S., et al., Tailoring the Thermal Conductivity of Paraffin Wax by Nano -fillers for Thermal Storage Applications, IHMTC, (2017). 10. D. K. Avasthi and G. K. Mehta, ‘Swift heavy ions in materials engineering and nanostructuring’, Springer 2011.
Authors : Ashwani Kumar and Ramesh Chandra*
Affiliations : Nanoscience Laboratory, Institute Instrumentation Centre, Indian Institute of Technology Roorkee, Roorkee - 247667, India
Resume : Metal oxides are potential candidates for energy storage devices like supercapacitors and rechargeable batteries because of their several advantages such as natural abundance and lower price. This research work is focused on the fabrication of 2-D metal oxide nanostructured materials, which can have superior electrochemical performance to the bulk materials. The several chemical methods are being used to synthesize metal oxide nanostructures which involve toxic reagents, solvents and introduction of byproducts. However, physical vapour deposition (PVD) methods provide an eco-friendly route to fabricate 2-D metal oxide nanostructures with clean surface morphology. In this report, the fabrication of binder free supercapacitor electrode of MnO2 nanosheet on Nickel (Ni) coated porous anodic aluminum oxide (AAO) substrate by DC magnetron sputtering, is presented for first time. Ni-coated porous AAO substrate acts as an excellent current collector, which enhances the specific capacitance of MnO2 to 649 F/g. The binder free symmetric supercapacitor device delivered a high areal capacitance (112.6 mF/cm2), specific capacitance (194.23 F/g), good cyclic ability (89.83% retention in capacitance after 5000 cycles), energy density (4.2 Wh/kg), and power density (1.4 kW/kg).
Authors : S. AghazadehChors, H. Viet-Nguyen, D. Muñoz-Rojas, C. Jiménez1, N.D. Nguyen, D. Bellet
Affiliations : Univ. Grenoble Alpes, CNRS, LMGP, F-38000 Grenoble, France Univ. of Liège, Département de Physique, B-4000 Liège, Belgium CEA-INES, LITEN, F-73375, 50 Avenue du Lac Léman, Le Bourget-du-Lac, France
Resume : There is a growing interest for flexible, efficient and low cost transparent electrodes and thus for many applications, including several related to energy technologies (photovoltaics, lighting, electro-chromism?) or displays (touch screens, transparent heaters?). When metallic nanowires are deposited to form random percolating networks, the latter can act efficiently as transparent electrodes. Such networks exhibit very good electro-optical properties and appear as an alternative to the reference material, i.e., indium tin oxide (ITO). The latter exhibits good physical properties and is used for many applications, however, the scarcity of indium, the associated high cost and lack of flexibility of ITO have prompted the search for alternative materials. The emerging transparent electrodes based on silver nanowire (AgNW) networks, exhibit excellent optical and electrical properties [1,2] fulfilling the requirements for many applications [3,4] including flexible devices. In addition, the fabrication of these electrodes involves low-temperature processing steps and upscaling methods, thus making them very appropriate for future use as TE for flexible devices. The aim of the contribution is two-folds. From an experimental aspect, the main physical properties of AgNW networks will be presented, including the influence of post treatments  or the network density and nanowire size [6,7]. The network stability will be discussed . We will show that atmospheric pressure spatial atomic layer deposition (AP-SALD) technique can drastically enhance the stability of AgNW networks thanks to a very conformal coating [9,10]. From a numerical approach, Monte Carlo modelling are developed to gain a deeper insight into the physical properties of AgNW networks. The main goals are : i/ studying different MNW geometrical associations, obtained by connecting adjacent AgNW forming nanostructured objects, and calculating their respective critical density to reach percolation. The question is can we lower the critical amount of material to reach percolative networks which would lead to less material consumption and higher optical transparency? ii/ The second part of the numerical work concerns the assessment of AgNW based electrodes integrated into solar cells by calculating the photo-generated carrier?s collection efficiency which is an important parameter for an efficient integration. 1. D.P. Langley, G. Giusti, C. Mayousse, C. Celle, D. Bellet and J.-P. Simonato, Nanotechnology 24, 452001 (2013). 2. T. Sannicolo, M. Lagrange, A. Cabos, C. Celle, J.-P. Simonato and D. Bellet, Small 12, 6052 (2016). 3. S. Sorel, D. Bellet, J.N. Coleman, ACS Nano 8, 4805 (2014). 4. D.P. Langley, G. Giusti, M. Lagrange, R. Collins, C. Jiménez, Y. Bréchet and D. Bellet, Solar Energy Mat. & Solar Cells 125, 318 (2014). 5. D.P. Langley, M. Lagrange, G. Giusti, C. Jiménez, Y. Bréchet, N.D. Nguyen and D. Bellet, Nanoscale 6 13535 (2014). 6. M. Lagrange, D.P. Langley, G. Giusti, C. Jiménez, Y. Bréchet and D. Bellet, Nanoscale 7, 17410 (2015). 7. T. Sannicolo, D. Muñoz-Rojas, N.D. Nguyen, S. Moreau, C. Celle, J.-P. Simonato, Y. Bréchet and D. Bellet, Nano. Lett. 16, 7046 (2016). 8. M. Lagrange, T. Sannicolo, D. Muñoz-Rojas, B. Guillo Lohan, A. Khan, M. Anikin, C. Jiménez, F. Bruckert, Y. Bréchet and D. Bellet, Nanotechnology 28, 055709 (2017) 9. D. Muñoz-Rojas and J.L. MacManus-Driscoll, Materials Horizons 1, 314 (2014). 10. D. Bellet, M. Lagrange, T. Sannicolo, S. Aghazadehchors, V. H. Nguyen, D. Langley, D. Muñoz-Rojas, C. Jiménez, Y. Bréchet, N.D. Nguyen, Materials in press.
Authors : Seckin Akin1,2,*, Erdinc Erol1, Mahir Gulen1,2, Erdi Akman2, Buket Bezgin Carbas3,4, Faruk Ozel1, Savas Sonmezoglu1,2
Affiliations : 1Department of Metalurgical and Materials Engineering, Karamanoglu Mehmetbey University, Karaman, TURKEY 2Nanotechnology R&D Laboratory, Karamanoglu Mehmetbey University, Karaman, TURKEY. 3Department of Energy Systems Engineering, Karamanoglu Mehmetbey University, Karaman, TURKEY 4Conducting Polymers and Energy Applications Laboratory, Karamanoglu Mehmetbey University, Karaman, TURKEY
Resume : As an alternative to Cu2ZnSnS4 (CZTS); Cu2XSnS4 (X = Mn2+, Ni2+) thin films were successfully synthesized by two-step electrodeposition method and employed as counter electrodes (CEs) in dye-sensitized solar cells (DSSCs) for the first time. Besides, the influence of deposition time and annealing process on the structural, morphological, and electrical properties of these thin films were investigated in detail. Experimental results confirmed that Cu2XSnS4 thin films show good crystallinity with preferential orientation along the (112) direction with a rough nanoscale surface. Furthermore, cyclic voltammogram (CV) analyses revealed that CNTS CE possesses the highest electrocatalytic activity, whereas CMTS has the lowest one. As a result, DSSC fabricated with the CNTS, CZTS, and CMTS CEs yielded a power conversion efficiency (PCE) of 4.44%, 3.71%, and 2.87%, respectively. This trend can be greatly attributed to the lower ionic radius of Ni2+ (0.72 Å) than that of Mn2+ (0.80 Å) and Zn2+ (0.74 Å), since larger ionic radius disturbs the crystallinity and obstacles the electron flow. The improved interaction between CE and redox electrolyte as a result of enhanced surface area in CNTS nanostructure can be an additional reason of higher PCE. Moreover, CNTS CE based cell exhibited a superior photocurrent transient (on/off capability) as well as obtained efficiency maintained the output performance even under 3600 s of light soaking (>95% of the initial Jsc remained). The easy synthesis, low-cost and excellent electrocatalytic property may help the CXTS thin films stand out as an alternative CE material in DSSCs. Acknowledgement–This study was supported by the European Union through the COST Action MP1407 “Electrochemical processing methodologies and corrosion protection for device and systems miniaturization (e-MINDS)”, and by the Scientific and Technological Research Council of Turkey (TUBITAK Grant Number 115M762) who provided financial support for this research.
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