Nanomaterials,Nanostructures and Nano devicesM
Hierarchical assembly of nano-scale building blocks
It is generally accepted that by improving control over the synthesis and assembly of nanoparticle building blocks it will be possible to produce materials with tailored and predictable properties. Furthermore, by incorporating hierarchical control into the assembly (through type, size and spatial distribution of the NPs) it will be possible to improve materials properties and performance and develop new functionalities
During the last few decades, an outstanding library of elemental, multinary, and multicompound nanoparticle building blocks with extremely precise controlled properties have become available. To take full advantage of the huge potential of these materials in their wide range of applications, equally precise assembly strategies and technologies need to be developed. The goal of this symposium is bring together groups developing nanoparticle assemblies, modelling the particle assembly mechanisms, and assessing the influence of order on the emergent functional properties of the assemblies for a variety of applications, to discuss the latest developments in the field and to inspire new ideas and start new collaborations in these areas. We will address current concerns/challenges in; (i) the formation of nanoparticles with sufficient control over size and monodispersity; (ii) solution based particle assembly techniques; (iii) scaling of these processes; (iv) the selection of assembly processes to provide control over emergent properties in single- and multi-component assemblies, and ; (v) the potential of computation to guide these developments.
Hot topics to be covered by the symposium
- Mechanisms and strategies for the preparation of nanoparticle clusters and 1D, 2D and 3D nanoparticle assemblies.
- Modelling of nanoparticle self- and directed-assembly
- In-situ characterization of nanoparticle assembling
- characterization of nanoparticle assemblies
- Modelling optical and transport properties of nanoparticles assemblies
- Use and integration of nanoparticle assemblies in biomedical, energy conversion and storage, optoelectronic, photonic, and other relevant applications
- Scale-up of nanoparticle synthesis and assembly processes
Tentative list of invited speakers
- Yadong Yin, University of California at Riverside, USA
- Y. Charles Cao, University of Florida, USA
- Bartosz A. Grzybowski, Northwestern University, USA
- Christopher B. Murray, IBM T. J. Watson Research Center, USA
- Elena Shevchenko, Argonne National Laboratory, USA
- Rafal Klajn, Weizmann Institute of Science, Israel
- Willem K. Kegel, Utrecht University, The Netherlands
- Luis Liz Marzan, CIC biomaGUNE, Spain
- Alexander Eychmüller, Technische Universitat Dresden, Germany
- Teresa Pellegrino, Italian Institute of Technology, Italy
Tentative list of scientific committee members
- Andrey Rogach, City University of Hong Kong
- Nicholas Kotov, University of Michigan, USA
- Claire Wilhelm, University Paris Diderot, France
- Jordi Arbiol, ICMAB, Spain
- Peter Reiss, CEA, France
- Kevin Ryan, Limerick University, Ireland
- Hong Liu, Shandong University, China
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Session I : Dermot Brougham
Authors : Willem K. Kegel
Affiliations : Van t Hoff Laboratory, Debye Research Institute, Utrecht University, Utrecht, The Netherlands
Resume : In this talk I will present recent progress in the creation and structure formation of several kinds of patchy colloids with various shapes and interactions between them. I will focus on recent experimental findings using colloids with soft (floppy) layers and broken symmetry. The soft layers deform at short distance between the particles, giving rise to directional bonds that in turn lead to low-dimensional structures such as bubbles, sheets and shells. We developed a simple computational model that globally reproduces the experimental observations. Yet, several questions remain and will be addressed.
Authors : Karolina Milowska1,2, Jenny Merlin1,2, Dermot Brougham,3 Jacek Stolarczyk1,2
Affiliations : 1.Photonics and Optoelectronics Group, Ludwig-Maximilians-Universität München, Amalienstr. 54,80799 Munich (Germany); 2.Nanosystems Initiative Munich (NIM), Schellingstr. 4, 80799 Munich (Germany) 3. School of Chemical Sciences Dublin City University, Dublin 9, Ireland
Resume : We present a model of assembly of nanoparticles into size-controlled nanoparticle clusters. In the process, the steric repulsion of the nanoparticles is gradually reduced by competitive stabilizer desorption arising from the presence of a tertiary silica phase.[1,2] The kinetics of assembly is analysed using Smoluchowski aggregation equation and Fuchs stability ratio dependent on nanoparticle-nanoparticle colloidal interactions. We show that by including a rigorous treatment of van der Waals, steric (osmotic and elastic) and magnetic interactions the experimental evolution of the size distribution obtained by dynamic light scattering can be correctly reproduced. The model can be extended to other systems based on polymer-decorated gold nanoparticles and includes the formation of multicomponent clusters (e.g. gold and iron oxide). We also show that the model of nanoparticle interactions can be of great use to predict the magnetic and colloidal properties of the resulting clusters as well as to design novel multifunctional nanoparticle clusters. 1.J. K. Stolarczyk et al, Angew. Chem. Int. Ed. 2009,48,175. 2.C.J. Meledandri et al, ACS Nano 2011,5,1747 3.K.Milowska et al, in preparation 4. J.K.Stolarczyk et al, to be submitted
Authors : Pai Liu, Shalini Singh, Ning Liu, Kevin M. Ryan
Affiliations : Materials and Surface Science Institute and Department of Chemical and Environmental Sciences, University of Limerick, Limerick, Ireland
Resume : The colloidal cadmium chalcogenides nanorods are under particular attention because of their tunable and directional emission spectra, high damage threshold and low energy formation processes, which lead to their perspective application in photovoltaic and optoelectronic devices. However, fully harnessing the enhancement from assembly requires complete orientational and positional order of the nanorods across an entire substrate. Herein, we describe electric field assisted perpendicularly aligned film of CdSexS1-x nanorods via a solution based method. This study involves the synthesis of semiconductor nanorods via a hot injection route and the subsequent deposition of nanorods suspension under a uniform DC field. We demonstrate this method can be applied to various types of semiconductor nanorods forming a highly orientated film and fabricating into practical devices. The numeric studies are extensively investigated on different types of rods to interpret the mechanism behind the alignment. It is also illustrated that the low production cost, and ability to assemble on any conductive substrate make this method a highly attractive alternative to epitaxially grown materials.
Authors : Suraj Naskar, Nadja C. Bigall
Affiliations : Leibniz Universit?t Hannover Institute of Physical Chemistry and Electrochemistry Callinstr. 3A D-30167 Hannover, Germany
Resume : Growth of noble metal domains on various semiconductor counterparts provides the opportunity to manipulate both the properties of metal and the semiconductor in the single segment. A general synthesis procedure to grow site-selective noble metal domains, namely Au, Pd and Pt, has been achieved on quasi 2D five monolayer thick CdSe nanoplatelets (NPLs). Optimization of the reaction parameters and of the type of metal precursor enables us to grow metal domains only at the corners and the shorter side edges (for Au and Pd), and all around the edges of the NPLs (for Pt). Different morphologies obtained for the different noble metals e.g. quasi spherical (for Au and Pt) and quasi rectangular (for Pd) are characterized both by bright field and dark field transmission electron microscopy, X-ray diffractometry, X-ray photoelectron spectroscopy and also by UV-Vis absorption and PL emission spectroscopy. All the nanoheteroplatelets show efficient charge carrier separation at the metal-semiconductor interface and are therefore suitable for applications in e.g. photocatalysis, which is examplarily shown for the degradation of methylene blue upon visible light irradiation. Furthermore, the assembly of these nanoheteroplatelets to form 3D networks under specific conditions is presented. S. Naskar, A. Schlosser, J. F. Miethe, F. Steinbach, A. Feldhoff, N. C. Bigall (2015): Site-Selective Noble Metal Growth on CdSe Nanoplatelets, Chemistry of Materials DOI: 10.1021/acs.chemmater.5b01110
Session II : Willem Kegel
Authors : Florian Guignard, Marco Lattuada
Affiliations : Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
Resume : The vast majority of the existing work on self-assembly of nanoparticles focused on spherical isotropic nanoparticles, which are easy to prepare for a broad range of materials. However, spherical isotropic particles do not offer many opportunities in terms of the variety of structures that can be prepared by self-assembly. In this work we present a more complex type of particles, namely Janus dumbbells, and discuss their self-assembly features. These particles can be synthesized in a broad range of sizes and aspect ratio, in addition to bearing asymmetric functionalized, with silane groups exclusively located on one hemisphere of the dumbbells. These particles have been functionalized in a broad variety of manners [1,2]. The hydrolysis and condensation of a silane precursor covered one lobe of the particles with a thin layer of silica. Upon removal of the polymeric template, silica nanobowls bearing a well-defined opening in their shell were prepared. Calcination of the template at 550 °C led to purely hydrophilic silica nanobowls, while the dissolution of the template in THF gave birth to Janus nanobowls having a thin polymer layer on their inner side, with a different reactivity of the inside and outside surfaces . Magnetic anisotropic nanoparticles were prepared by starting with magnetic beads as seed particles. The asymmetric dumbbells, with different aspect ratios, were self-assembled in the presence of an external magnetic field, in order to explore the effect of their aspect ratio on the formation of chains. By creating dipolar dumbbells, we prepared Janus nanomotors by selectively attaching citrate-coated platinum nanocrystals on one hemisphere.
Authors : Alessio Zaccone
Affiliations : Technische Universit?t M?nchen Physik-Department
Resume : Self-assembly of macromolecules via non-covalent physical bonding often implies that the binding energy between two molecules is on the order of a few kTs. Therefore, widely used paradigms employed in colloidal science such as diffusion-limited irreversible aggregation are not applicable because thermal breakup of bonds is important and it may induce significant restructuring inside a cluster, besides affecting the self-assembly kinetics. The restructuring process may lead to different self-assembly morphologies (micelles, filaments, compact aggregates etc). We recently develop a new approach which describes self-assembly via diffusion-controlled transport of nanoparticles/molecules in solution crucially allowing for spontaneous thermal bond-breakup. The framework has been successfully applied to self-assembly and gelation of thermoresponsive polymers in water (in core-shell and block-copolymer form) to obtain information about the effective bonding interaction which is otherwise not accessible, in combination with light scattering and neutron scattering experiments. Application of this framework to protein self-assembly allows us to relate the aggregate morphology and polymorphism to intermolecular interaction parameters.
Authors : Fadwa El Haddassi, Dermot Brougham
Affiliations : Dublin City University
Resume : The biomedical applications of magnetic nanoparticle clusters (NPCs) in MRI for both drug delivery and hyperthermia are particularly dependent on the ability to control cluster size, architecture and surface composition . Our group recently developed a method for producing stable monodisperse suspensions of NPCs by a novel process called competitive stabilizer desorption (CSD)  which allows us to control NPC size while maintaining monodispersity in the range from 40-500 nm. Here we describe a modified CSD process, water interface CSD (WI-CSD), which makes the process more robust and facilitates its scale-up. We have applied WI-CSD to the assembly of other types and combinations of NPs, including combinations of γ-Fe2O3 and metal ferrite NPs. A method for the transfer of nanoparticle assemblies from organic to aqueous media, without change in size or loss of monodispersity, using a range of different surface agents has been also developed. The effect of NPC composition and the surface agents on the magnetic resonance properties of the NPCs in suspension will be also described. 1) Lartigue L, Hugounenq P, Alloyeau D, Clarke SP, L?vy M, Bacri JC, Bazzi R, Brougham DF, Wilhelm C and Gazeau F; ACS Nano, 2012, 6, 10935-10949. 2) Stolarczyk JK, Swapankumar G and Brougham DF, Angew. Chem. Int. Ed. 2009, 48, 175-178.
Authors : K. Z. Milowska , Habeeb M. M. Abubaker , Markus Doblinger , J. Rodriguez Fernandez , J. K. Stolarczyk 
Affiliations : Department of Physics and Center of Nanoscience, Ludwig-Maximilians University Munich, Amalienstr. 54, 80799 Munich, Germany Department of Chemistry, Ludwig-Maximilians-University Munich, Butenandtstrasse 5-13 (E), 81377 Munich, Germany
Resume : The hierarchically-ordered nanoparticle assemblies attract a lot of research activity because of wide range of potential applications. The assemblies of ultra-small gold nanoparticles (usNP, nanoclusters) due to distinctive quantum confinement and geometric effects are of particular interest. Here, we present results of extensive and systematic studies of periodically assembled (1D, 2D & 3D) ligand-protected Au usNP. Our theoretical studies are based on the ab initio calculations in the framework of the density functional theory (DFT) including van der Waals interactions on one hand and colloidal stability theory (CST) on the other hand. Eight different Au usNP (Aum, m=11,13,16,19,38,55,79,144) protected with different lengths of thiolate ligands (-S(CH2)nCH3, n=0,..,7) are considered. We focus on interactions between usNP which are a subject of hot debate and crucial for the design of functional devices. We compare DFT and CST approaches and show that ligand interactions are of more importance for obtaining stable assemblies of Au ultra-small nanoparticles rather than van der Waals interactions between their cores. Moreover, we found that fcc is energetically most preferable type of arrangement. There theoretical predictions are compared with experimental observations (HRTEM, SAXS) obtained for synthesized supracrystals of Au144(SC6H13)60 nanoclusters.
Session III : Massimo Morbidelli
Authors : Alexander O. Govorov
Affiliations : Department of Physics, Ohio University, Athens, OH, 45701
Resume : Bio-assembled nanostructures incorporating both metal and semiconductor nanocrystals exhibit strong optical absorption associated with exciton and plasmon resonances [1,2]. When a system includes chiral molecules, the Coulomb and electromagnetic interactions between excitons and plasmons are able to alter and enhance circular dichroism (CD) of chiral molecular dipoles. Especially strong enhancement factors for the molecular CD signals can be achieved using plasmonic hot spots. Strong CD signals can also appear in purely plasmonic systems with a chiral geometry and a strong particle-particle interaction . Another class of optical phenomena in bio-assembled nanostructures concerns the quantum and classical interference effects when interactions between nanocrystals lead to the Fano effect, plasmon-induced energy transfer, transparency window , unusual plasmonic modes, etc. Potential applications of plasmonic nano-assemblies are in bio-sensors, chiral chemistry and materials for optics and energy.  A. O. Govorov, G. W. Bryant, W. Zhang, T. Skeini, J. Lee, N. A. Kotov, J. M. Slocik, and R. R. Naik, Nano Letters 6, 984 (2006).  J. Lee, P. Hernandez, J. Lee, A.O. Govorov, and N. A. Kotov, Nature Materials 6, 291 (2007).  A. Kuzyk, R. Schreiber, Z. Fan, G. Pardatscher, E.-M. Roller, A. H?gele, F.C. Simmel, A. O. Govorov, T. Liedl, Nature 483, 311 (2012).  H. Zhang, H. V. Demir, A.O. Govorov, ACS Photonics 1, 822 (2014).
Authors : Madathumpady Abubaker Habeeb Muhammed,1,3 Markus Döblinger,2,3 and Jessica Rodríguez-Fernández,1,3
Affiliations : 1Department of Physics and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Munich (Germany), 2Department of Chemistry, Ludwig-Maximilians-Universität München, Munich (Germany) 3Nanosystems Initiative Munich (NIM), Munich (Germany)
Resume : Combining two different classes of plasmonic materials, namely metallic and vacancy-doped semiconductor nanoparticles,1 into a well-defined colloidal assembly is important to investigate the plasmonic crosstalk between them. Here we combine electrostatic self-assembly of semiconductor nanoparticles (CdSe) and subsequent Cd2+/Cu+ cation exchange to prepare an anisotropic core-shell nanoparticle cluster (NPC) comprising a gold nanorod (AuNR) core and a copper selenide supraparticle shell (AuNR@Cu2-xSe, x≥0).2 When in stoichiometric form (x=0), the AuNR@Cu2Se NPCs exhibit plasmon bands originating exclusively from the metal core (AuNR). However, under aerobic conditions the Cu2Se shell undergoes Cu(I) vacancy doping (x>0) leading to a higher density of charge carriers (in this case, holes). This gives rise to strong changes in the near-infrared (NIR) optical properties of the AuNR@Cu2-xSe NPCs. Our experimental and optical modelling results confirm that depending on the vacancy doping level of the shell, the NIR optical response of the cluster is dominated by the plasmon modes from the metal core alone, from the semiconductor shell alone or from both. Under oxidative and reductive conditions it is possible to reversibly control and select which plasmon modes will dominate the NIR optical response of the clusters. In short, we present a unique nanosized colloidal assembly that can exhibit all-metallic, metallic-semiconductor or all-semiconductor NIR localized surface plasmon resonances with strong absorbing- and near-field enhancing properties. 1. I. Kriegel, C. Jiang, J. Rodríguez-Fernández, R. D. Schaller, D. V. Talapin, E. da Como, J. Feldmann, J. Am. Chem. Soc. 2012, 134, 1583. 2. M.A.H. Muhammed, M. Döblinger, J. Rodríguez-Fernández, submitted 2015.
Authors : Rumi Tamato1, Jiaji Cheng1, Emilie Pouget1, Sophie Lecomte1 , Philippe Barois2, Ashod Aradian2, Virgine Ponsinet2,Reiko Oda1, Marie-Hélène Delville3*
Affiliations : 1 CBMN, Allée Geoffroy Saint Hilaire, Bât B14, 33600 Pessac 2 CRPP, CNRS UPR 8641, Universite of Bordeaux 115 avenue du docteur Schweitzer F-33608 Pessac Cedex FRANCE 3 ICMCB, CNRS UPR 9048, Universite of Bordeaux 87 Avenue du Dr Schweitzer F-33608 Pessac Cedex FRANCE
Resume : In the field of emerging nanoscale materials with switchable properties chiral structures like helices or twisted ribbons are of great interest because of their intrinsic optical and mechanical properties. In this contribution, we present a study about the properties of SiO2 and SiO2@Au helical nanosprings synthesized by an original and simple technique from organic nanotubes through inorganic transcription. Beside their potential applications in NEMS, ranging from physical sensing and signal processing to ultra-low power radio frequency signal generation, thanks to their striking features these 1D nano-objects can also exhibit interesting photonic properties. The originality of the synthesis method consists in the possibility to obtain 3D organized nanostructures with specific morphology and properties based on 1D objects. Hybrid nano-helices are synthesized using amphiphilic organic chiral self-assemblies forming very well defined helix or ribbons structures and exploits them as templates for inorganic nanomaterial formation1. Their bio-inspired mineralization creates silica nano-helices with very well controlled morphologies usable in functional nanodevices. In this case they were used to prepare a large variety of gold nanoparticledecorated helical surperstructures.We can control both handedness and structural metrics by controlling the sizes of the GNPs building blocks varying from 3.5 nm-6 nm as well as reach an overall coverage of the silica (for SERS applications),2 and the silica nanohelices or twisted ribbons. The resulting objects exhibit well-defined chiral arrangement of the GNPs following the chirality of the silica helices through electrostatic intereactions. A clear surface plasmon resonnance was observed in UV visible range. These nanohybrid systems are under study for photonic applications such as chiral metamaterials and optical sensors based on the 3D network of GNPs. Project funded by ANR SIMI8 programm 2010-2014: NANOSPRINGS and Labex Amadeus 1. (a) Delclos, T.; Aime, C.; Pouget, E.; Brizard, A.; Huc, I.; Delville, M.-H.; Oda, R., Individualized silica nanohelices and nanotubes: Tuning inorganic nanostructures using lipidic self-assemblies. Nano Letters 2008, 8 (7), 1929-1935; (b) Okazaki, Y.; Cheng, J.; Dedovets, D.; Kemper, G.; Delville, M.-H.; Durrieu, M.-C.; Ihara, H.; Takafuji, M.; Pouget, E.; Oda, R., Chiral Colloids: Homogeneous Suspension of Individualized SiO2 Helical and Twisted Nanoribbons. ACS Nano 2014, 8 (7), 6863-6872. 2. Tamoto, R.; Lecomte, S.; Si, S.; Moldovan, S.; Ersen, O.; Delville, M.-H.; Oda, R., Gold Nanoparticle Deposition on Silica Nanohelices: A New Controllable 3D Substrate in Aqueous Suspension for Optical Sensing. J. Phys. Chem. C 2012, 116, 23143-23152.
Authors : A.J. Blanch [1,3], M. Doeblinger [2,3], J. Rodriguez-Fernandez [1,3]
Affiliations : 1. Department of Physics and Center for NanoScience (CeNS), Ludwig-Maximilians-Universitaet Muenchen, Munich (Germany) 2. Department of Chemistry, Ludwig-Maximilians-Universitaet Muenchen, Munich (Germany) 3. Nanosystems Initiative Munich (NIM), Munich (Germany)
Resume : Noble metal nanoparticles with spiked surfaces are considered excellent candidates for sensing and field enhancement applications due to the high and localized electric field enhancement that occurs at their branch tips. We have synthesised highly-branched gold nanoparticles in a rapid, one-pot, room temperature process in the presence of the non-ionic surfactant Triton X-100 (TX-100). These nanoparticles possess hollow cores and thin branches, where the branch density and overall size can be controlled through adjustment of synthesis conditions, allowing the plasmon band to be tuned over the NIR (near-infrared) spectral range (700-2000 nm). We present insights into the mechanism of nanoparticle formation, and show that these hollow nanoparticles have high sensitivity to the surrounding medium. This sensitivity is shown to be improved upon density gradient separation into fractions of improved size distribution. We will also discuss our latest results on the optical properties of single nanoparticles and assemblies thereof. Overall, our results indicate that the combination of hollowness and branching in one nanoparticle type offers a competitive advantage in terms of light-absorbing and field-enhancing properties, and therefore, these nanoparticles are promising candidates for sensing and theranostic applications.  A. J. Blanch, M. Doeblinger, and J. Rodriguez-Fernandez, Small, in press (2015)
Session IV : Alexander Govorov
Authors : Amelie Heuer-Jungemann (a), Pascal H. Harimech (a), Johanna Midelet (a), Afaf H. El-sagheer (b), Tom Brown (b), Antonios G. Kanaras (a, c).
Affiliations : (a) Physics and Astronomy, University of Southampton, Southampton, SO171BJ, United Kingdom (b) Department of Chemistry, University of Oxford Chemistry Research Laboratory, Oxford OX1 3TA, United Kingdom (c) Institute for Life Sciences, University of Southampton, Southampton, So171BJ, United Kingdom
Resume : The ability to control the bottom-up self-assembly process of nanoparticles is of continuous research interest. The ultimate aim is to master the fabrication of long range structures with hybrid properties deriving from a specific combination of their individual building blocks. In order to achieve this great degree of programmability, it is important to develop a set of tools that allow manipulating the way that particles assemble to each other. In this presentation, I will discuss the current relevant developments in my group using DNA, light, peptides and polymers to master the assembly of nanoparticles. I will particularly focus on gold nanoparticles but then I will expand my discussion on other types of nanoparticles including upconversion and magnetic nanoparticles. (1) Relevant Reference: (1)Heuer-Jungemann, A.; Kirkwood, R.;El-Sagheer, A.; Brown, T.; Kanaras, A. G. Nanoscale 2013, 5 (16), 7209-7212
Authors : Hongkang Wang and Andrey L. Rogach
Affiliations : Department of Physics and Materials Science & Centre for Functional Photonics City University of Hong Kong
Resume : Tin dioxide (SnO2) is an important n-type wide-bandgap semiconductor with applications in transparent conductive films, gas sensors, lithium ion batteries, and solar cells . For many of these applications, complex three-dimensional hierarchical structures assembled from well-defined low-dimensional nanosized building blocks are of a special importance. We outline synthetic strategies of hierarchical SnO2 nanostructures in terms of the dimension and the facet control, creation of porous and hollow structures, as well as modification of their optical properties by doping with other elements [2-6]. We further review recent progress in our design of composite nanostructured Sn−Ti−O ternary systems [7-9], which are promising materials for lithium ion batteries .
Authors : Eoin Fox1, Fadwa El Haddassi1, Jose Hierrezuelo1, Jacek Stolarczyk2 and Dermot Brougham1*
Affiliations : 1School of Chemical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland. 2 Photonics and Optoelectronics Group, Department of Physics and Center for NanoScience (CeNS), Ludwig-Maximilians-Universit?t Munich, Amalienstrasse 54, 80799 Munich, Germany
Resume : Robust, cheap and scaleable routes to monodisperse multi-component nanoparticle assemblies are required for a wide range of biological and materials applications. Here we describe recent advances in a novel process, competitive stabilizer desorption (CSD), [1,2] for preparing monodisperse assemblies from a range of starting nanoparticle types and combinations. With CSD the relative monodispersity of the assemblies improves, as compared to the starting particles, and assemblies can be prepared over a broad size range. A detailed kinetics study will be presented that reveals the mechanism and identifies initial conditions for controlled assembly. CSD uses cheap materials, is reproducible, robust and scaleable, and uniquely the particle and cluster size can be selected independently, as can the final surface chemistry, allowing detailed evaluation of the contribution of each of these component to the emergent properties. The potential of magnetic nanoparticle assemblies prepared by CSD for MRI-guided drug delivery applications will be described. 1) C. J. Meledandri, J. K. Stolarczyk, D. F. Brougham, ACS Nano 2011, 5, 1747-1755. 2) J. K. Stolarczyk, D. F. Brougham, Angew. Chem. Int. Ed. 2009, 48, 175-178.
Authors : Priyanka Dey,[1,2] Kristofer J. Thurecht, Idriss Blakey, Peter M. Fredericks and Jessica Rodríguez-Fernández[1,2]
Affiliations : Department of Physics and CeNS, Ludwig-Maximilians-Universität München, Munich, Germany. Nanosystems Initiative Munich (NIM), Munich, Germany. Australian Institute of Bioengineering and Nanotechnology and Centre for Advanced Imaging, University of Queensland, St. Lucia, Australia. School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Australia.
Resume : Plasmonic metal nanoparticles (NPs) display localized surface plasmon resonances (LSPRs) that can be tuned by controlling their shape and size, but also by forming nano-assemblies. Ordered nano-assemblies contribute to enhanced plasmonic properties, including coupled LSPR modes, plasmonic heating and surface enhanced Raman scattering (SERS). Hence, they find applications in photothermal therapy, catalysis, SERS chemical sensors, SERS bio-diagnostic agents and many more. Motivated by this, here we have developed colloidal gold nano-assemblies with controlled morphology, number of NPs per assembly (aggregation number) and interparticle distance. Our strategy involves the utilization of molecular linkers in a colloidal self-assembly approach. Following this, we investigated the role of structurally different tailor-made molecular ligands in the formation of stable colloidal gold nano-assemblies. Depending on the type of ligand employed i.e., organic molecule, linear polymer or branched polymers, we observed the formation of various 1D, 2D and 3D gold nano-assembly morphologies. A good control over the aggregation number and morphologies was achieved. These included dimers, nanochains, nanobranches, nanoplates, core-satellite as well as 3D globular structures. They were characterized by UV-Vis, DLS, AFM and cryo-TEM at various tilt angles. We also observed a strong dependence of the LSPR coupling and SERS signal enhancement on the nano-assembly morphology and its aggregation number. Such customized gold nano-assemblies further demonstrated potential for applications as SERS sensors. 1. Daniel, M. et. al., Chem. Rev. 2004, 104, 293−346. 2. Ko, H. et. al., Small, 2008, 4(10), 15761599. 3. Dey, P. et. al., Langmuir, 2013, 29 (2), 525533.
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Authors : Jan Paczesny, Robert Hołyst
Affiliations : Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw, Poland
Resume : We search for the rules which connect the functionality of the self-assembled nanostructures and the design building blocks of which it is composed. We study subtle parameters of the molecular design, i.e. stiffness, amphiphilic balance and geometrical packing. We find that the tendency for self-assembly of ligand molecules can be transferred to other species, i.e. nanoparticles. The proper design of capping ligands or addition of judiciously chosen molecules result in control over 2D self-assembly of nanoparticles. The advances in manipulation of nanoparticles allowed us to prepare novel surface enhance Raman spectroscopy (SERS) platform according to true bottom-up approach. Three consecutive steps were utilized. First, gold nanoparticles were deposited on a solid substrates. Afterwards such substrates were used for the chemical vapor deposition process of gallium nitride nanowires growth. On such scaffolding a third step of material fabrication was performed, i.e. deposition of gold microflowers. The final morphology was controlled at each step to tailor the properties for the desired purposes. The recorded SERS enhancement factor was around 107 for p mercaptobeznoic acid. SERS spectra were reproducible both across a single sample and between different platforms. The material proved to be very mechanically stable. Our platforms were suitable for biological and biomedical applications. We demonstrated the label free detection of DNA.
Authors : Boris N. Feigelson, James A. Wollmershauser, Kedar Manandhar
Affiliations : Boris N. Feigelson US Naval Research Laboratory; James A. Wollmershauser US Naval Research Laboratory; Kedar Manandhar ASEE Postdoctoral Fellow residing at U.S. Naval Research Laboratory
Resume : With designed bulk nanostructures, one could potentially combine properties that are mutually exclusive in a single bulk material, and, as a result, dramatically improve the desired performance. However, a major research challenge and roadblock is how to produce 3D nanostructured materials consistently with the required phases arranged in designated spatial order that are at the same time fully dense without porosity and detrimental phases. Known state-of-the-art techniques for producing bulk nanostructures cannot simultaneously meet all these requirements. As a result, the inherent properties of such bulk monolithic nanostructured materials are greatly unknown and unexplored. We developed an Enhanced High Pressure Sintering (EHPS) approach to consolidate oxide, metal, and semiconductor nanoparticles into 3-dimensional nanostructured materials. EHPS incorporates stringent environmental control and utilizes high pressures to break agglomerates while simultaneously exploiting the increased pristine surface potential of nanoparticles for surface-energy-driven densification without microstructural changes. Using this approach, monolithic nanocrystalline transparent ceramics with grain size bellow 30 nm are demonstrated. Such ceramics exhibit a 30% increase in hardness over a corresponding order of magnitude reduction in grain size and suggest that Hall-Petch type (strengthening via grain size reduction) relations exist in ceramics at least down to 30nm.
Authors : Norbert NAGY, Dániel ZÁMBÓ, Szilárd POTHORSZKY, András DEÁK
Affiliations : Institute for Technical Physics and Materials Science, HAS Centre for Energy Research, P.O. Box 49, H-1525 Budapest, Hungary
Resume : In this work we report about the preparation of ring shaped nanoparticle arrays prepared from gold nanoparticles. The nanoparticle solution was drop-casted on a sacrificial Langmuir-Blodgett monolayer prepared from polystyrene (sub)microspheres which served as a template for the assembly process. During the solvent evaporation, the gold nanoparticles are arranged under the template particles into a ring-shaped pattern and locked into position after the complete drying of the film. By investigating the location and the typical patterns of the particle deposits by scanning electron microscopy, the different consecutive stages of the structure evolution could be identified. While previous literature results refer to the high nanoparticle concentration regime of the approach, resulting in the formation of thick rings with several particle layers , or even continuous particle deposits between neighboring particles , here we show how this technique can be used for the preparation of nanoparticle rings, composed of a single chain of nanoparticles. Based on boundary element simulations, the structure is promising for SERS application due to the highly localized fields that emerge as a result of the chain structure.
Authors : Gihan Joshua, Michaela Meyns, Pablo Guardia, Andreu Cabot
Affiliations : Catalonia Energy Research Institute - IREC, Centre Tecnologic de la Quimica de Catalunya - CTQC, Institucio Catalana de Recerca i Estudis Avancats - ICREA
Resume : In recent years much attention has been directed towards the fabrication of materials on the nanoscale that combine several functional components. The co-assembly of two or more types of nanoparticles with differing properties into larger colloidal particles, nanoparticle clusters (NPCs), presents an opportunity to create new hierarchical nanomaterials. NPCs are especially advantageous due to their potential multifunctionality while at the same time maintaining low colloidal sizes and properties not seen in their bulk counterparts. Of particular interest are assembly methods that utilize nanoparticle-micelle structures that are formed in emulsions, which allow for the directed assembly of nanoparticles into NPCs with spherical morphologies. In this work we investigate several different surfactants for micelle-assisted assembly methods for the preparation of NPCs, including hexadecyltrimethylammonium bromide (CTAB) and dodecyltrimethylammonium bromide (DTAB) cationic surfactants as well as Pluronic triblock copolymers. Upon evaluation of the advantages and pitfalls of the various assembly approaches, several are chosen for the creation of binary nanoparticle clusters (PbS:PbSe, PbSe:PbTe, Fe3O4:CdSe) for potential thermoelectric and biomedical applications.
Authors : K. Brassat, Ch. Brodehl, J.K.N. Lindner
Affiliations : Dept. of Physics, University of Paderborn, Germany; Center for Optoelectronics and Photonics Paderborn CeOPP, Paderborn, Germany
Resume : During the last decades the synthesis, modification and functionalization of nanoparticles has been intensively studied. In order to fully exploit their properties, it is essential to control the nanoparticles position, allowing to connect the nanoobjects to the macro-world. For a sufficient statistics it is desirable to contact many nanoparticles in parallel. To this end we have developed a template-assisted self-assembly technique which allows us to create inside microfluidic channels millimeter long rows of nanogap electrodes attached to macroscopic contacts. Dielectrophoresis is used to trap particles in the inhomogeneous electric field formed between the electrodes. For single particle trapping the electrodes gap size needs to be tuned to the particle dimensions. For this polystyrene-spheres from colloidal suspensions are arranged in a linear chain in trenches on Si-surfaces by means of convective self-assembly. The spheres act as shadow masks in a subsequent metal deposition step. Opposing pairs of sharp metallic nanotips remain after sphere removal, with tip distances adjustable from several hundred nm to less than 30 nm. We demonstrate that an applied voltage leads to strong field enhancements at the tips. The field gradients between tips are exploited to arrange fluorescent core-shell SiO2 nanoparticles in the channel. Fluorescence microscopy and scanning electron microscopy are used to study the dielectrophoretic arrangement.
Session VI : Stefano Sacanna
Authors : Erik Reimhult
Affiliations : Institute for Biologically inspired materials, Department of Nanobiotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
Resume : The encapsulation and local delivery of drugs continues to be an important challenge in medicine. Successful concepts that allow for both stable encapsulation, that protects the drug during circulation, and efficient release at the desired site of delivery could greatly enhance the efficacy of already existing drug treatment; it would enable new and more potent drugs to be used with less side effects. One approach to reach this goal is to create hybrid capsules that both exhibit stealth coatings and a means to externally trigger content release. We present our work to design superparamagnetic, core-shell nanoparticles for controlled interaction with amphiphilic membranes; this work has allowed us to incorporate nanoparticles into the walls of e.g. lipid and block-copolymer membrane nanocapsules. We demonstrate methods to control the size, shape and wettability of superparamagnetic iron oxide nanoparticles and how this critically determines the ability of the nanoparticles to partition stably and with retained function into capsule membranes. New methods to efficiently assemble such capsules with high nanoparticle content in the membrane will be presented. Capsule structures are investigated by scattering techniques, optical and electron microscopy. The release of small molecules from stealth capsules by application of various alternating magnetic field sequences is demonstrated as function of structure. The uptake and toxicology in cell cultures was also investigated.
Authors : Siming Yu, Anna Laromaine, Anna Roig
Affiliations : Nanoparticles and Nanocomposites Group (www.icmab.es/nn), Institut de Ci?ncia de Materials de Barcelona, Consejo Superior de Investigaciones Cient?ficas (ICMAB-CSIC), Campus de la UAB, Bellaterra, Catalunya, E-08193 Spain
Resume : Simple approaches to synthesize hybrid magneto-plasmonic nanoparticles with anisotropic plasmonic shapes avoiding cytotoxic reactants are in high demand. Microwave heating is an attractive non-conventional energy source for chemical synthesis due to the high acceleration of the performed reactions. In comparison to other conventional heating methods, microwave radiation avoids temperature gradients decreasing occurrences of asynchronic nucleation and heterogeneous nanocrystal growth. In addition, microwaves heats polar substances rapidly and intensely promoting selective heat at desired sites. Thus, complex multi?material heterostructures can be fabricated. We will report on a facile, fast and bio-friendly microwave-assisted polyol route to synthesize gold nanotriangles decorated by a monolayer of iron oxide nanoparticles. The nanotriangles are readily dispersable in water, superparamagnetic at room temperature and display local surface plasmon resonance in the near infrared region. In addition, these hybrid nanostructures can self-assemble as a monolayer at the liquid-air interface. The effect of the reaction conditions and the magnetic and plasmonic properties of the nanoconstructs will be presented.
Authors : Pablo Guardia,1,2,3 Maria Elena Materia, 1 Sathyanarayanavarma Ayyappan, 1 Manuel Pernia Leal,1,4 Riccardo Di Corato1,5 and Teresa Pellegrino,1,5
Affiliations : 1) Nanochemistry, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy 2) Catalonia Energy Research Institute - IREC, 08930 Sant Adrià del Besos, Barcelona, Spain 3) Centre Tecnològic de la Química de Catalunya - CTQC, 43007 Tarragona, Spain 4) Diagnostic Unit, Andalusian Centre for Nanomedicine and Biotechnology, BIONAND, Parque Tecnológico de Andalucía, Málaga, Spain 5) National Nanotechnology Laboratory of CNR-NANO, via per Arnesano km 5, 73100 Lecce, Italy
Resume : Iron oxide nanocubes (IONCs) represent one of the most promising iron-based nanoparticles for both magnetic resonance image and magnetically mediated hyperthermia. The control aggregation of IONCs into magnetic nanobeads (MNB) could lead to an improvement of the original performance of the single IONCs increasing their performance. Here, we have set a protocol to control the aggregation of multiple highly magnetically interacting IONCs within a polymeric shell in a so-called (MNB) of mesoscale size (200 nm). By the comparison with individual coated nanocubes, we here elucidate the effect of the aggregation on the Specific Adsorption Rates (SAR) and on the T1 and T2 relaxation times. We found that while SAR values decrease as IONCs are aggregated into MNBs, relaxation times show very interesting properties with outstanding values of r2/r1 ratio for the MNBs with respect to single IONCs. Moreover, the measurements performed in different solvents allow elucidating a different energy dissipation process for MNBs which accounts for the low heat performance of the latter.
Session VII : Erik Reimhult
Authors : A.M. Bittner
Affiliations : CIC nanoGUNE and Ikerbasque, San Sebastián, Spain
Resume : Tobacco Mosaic Virus (TMV) is one of the best examples for self-assembly, especially of the tubular protein sheath. Its stability allows a use as template for the assembly of nanoscale materials, for example to enhance ferrofluid performance by organising ferrite nanoparticles , or to produce thin tubular layers of nanoparticles, metals, and oxides . With a view to applications and devices, it is, however, not yet established how useful such new materials are . Usually, the assembly or the required chemical modifications are carried out in aqueous solution. However, many plant viruses, such as TMV, tolerate complete desiccation [4,5]. In between these extremes, water can adsorb and wet virus structures, giving rise to a plethora of phenomena . The interaction with organic solvents and ionic liquids is much less known, but is key for exploring a much wider range of materials [3,5].  Z. Wu, A. Mueller, S. Degenhard, E. Ruff, F. Geiger, A.M. Bittner, C. Wege and C. Krill III, ACS Nano 8 (2010), 4531  A.A. Khan, E.K. Fox, M.L. Górzny, E. Nikulina, D.F. Brougham, C. Wege, A.M. Bittner, Langmuir 29 (2013) 2094  J.M. Alonso, M.L. Gorzny, A.M. Bittner, Trends Biotechnol. 31 (2013) 530  I. Amenabar, S. Poly, W. Nuansing, E.H. Hubrich, A. Govyadinov, F. Huth, R. Krutokhvostov, L. Zhang, M. Knez, J. Heberle, A.M. Bittner, R. Hillenbrand, Nature Commun. 4 (2013) ncomms3890  J.M. Alonso. T. Ondarçuhu, A.M. Bittner, Nanotechnol. 24 (2013) 105305  J.M. Alonso, F. Tatti, A. Chuvilin, K. Mam, T. Ondarçuhu, A.M. Bittner, Langmuir 29 (2013) 14580
Authors : F. Khelifa*, Y. Habibi, L. Bonnaud, Ph. Dubois
Affiliations : University of Mons, Institute of Research in Science and Engineering of Materials, Belgium
Resume : Nanostructuration of materials is one of the main challenges for the nanocomposite community in the development of new performant materials with specific properties. Currently, numerous efforts are focused on the use of compounds from renewable resources, and cellulose nanocrystals (CNC) are attracting a great deal of interest due to their biodegradability in addition to appealing intrinsic properties such as low density and good mechanical properties. More importantly, pure CNC films exhibit spectacular optical properties originating from their ability to self-organize into liquid crystalline arrangements. Nevertheless, the resulting films are highly hygroscopic and brittle limiting their potential applications, especially in films, membranes or coatings. Therefore, the preservation of remarkable optical properties for their use in nanocomposite materials is extensively sought. In the present work, an original and simple approach based on the collective sticking of CNC, constituting the building blocks, with the help of a DGEBA/TGPAP-based epoxy resin is proposed. Scientific findings suggest that the preservation of CNC optical properties at high concentrations, the enhanced protection from water degradation and the flexibility improvement of the synthesized films are ensured by a good compatibility of the CNC and the resin. Moreover, the presence of hydroxyl groups in the CNC structure allows a toxic-free curing of the resin to be realized.
Authors : B. Kalska-Szostko*, U.Wykowska*, D. Satuła#
Affiliations : * Institute of Chemistry, University of Bialystok, Hurtowa 1, 15-399 Białystok, Poland #Department of Physics, University of Bialystok, Ciolkowskiego 1L, 15-245 Białystok, Poland
Resume : Cooperation of few functionally different spices in one heterostructure in general is not prohibited. However, the conditions for its merging should be find out in any case. Magnetic nanoparticles, carbon nanostructure and/or biologically active particles is possible to link by bond activation between immobilized proteins and surface of the nanostructures . Not only magnetic or noble metals nanoparticles are key players used in nanotechnology but also carbon structures in nanosize (nanodiamonds, fullerenes, nanotubes) have shown widespread interest due to their unique specification. Each of these structures shows extraordinary magnetic, electrical, mechanical and optical properties. Therefore by linking more than two different items combination of the characteristic features can be obtained. Similarly to magnetic nanoparticles surface of the carbon structures should be chemically modified by attachment of various (needed) functional groups. This opens possibility for creation of hierarchical structures such as composites or hybrid nanostructures. Fabrication of heterostructures causes that carbon nanomaterials brings to medicine possibility of electronic science . In this study, nanocomposites from different kind of nanoparticles were fabricated, and compared. In the first step, various magnetic nanoparticles were synthesized and both with carbon nanostructures were functionalized at the surface to amine or carboxyl groups. Finally either particles were used as a building blocks for composites fabrication and with vitamin-biotin immobilization. The resulting nanocomposites were tested by infra-red spectroscopy, Transmission Electron Microscope, X-ray diffraction, Mössbauer spectroscopy.  K.Woo, J.Hong, J.P.Ahn., Journal of Magnetism and Magnetic Materials 293 (2005) 177-181  Z.Markovic, V.Trajkovic, Biomaterials 29 (2008) 3561-3573
Authors : Jana Segmehl, Alessandro Lauria, Tobias Keplinger, Ingo Burgert
Affiliations : ETH Zurich, Wood Material Science; ETH Zurich, Multifunctional Materials; ETH Zurich, Wood Material Science; ETH Zurich, Wood Material Science;
Resume : The concept of composite materials often found in nature, combining materials of distinguished chemistry like polymers and minerals in a highly ordered arrangement, yields outstanding multifunctional properties. In this work we used wood derived hierarchical cellulose scaffolds for the assembly of multifunctional materials through nanoparticle infiltration. Chemical delignification procedures on bulk wood increases the accessibility of the structure down to the nanoscale, while the hierarchical organization of the porous material is preserved. The gain in porosity of the scaffold relates to the amount of removed lignin, which can be controlled by temperature and duration of delignification processes. For the formation of nano-composite materials, the prefabricated wood scaffold was infiltrated with pre-synthesized, ultra-small fluorescent Eu:HfO2 particles. These were successfully incorporated in the sub-micron structures of wood, showing the possibility to realize hierarchically organized materials by the bottom-up templating of inorganic functional nanoparticles into wood derived organic scaffolds. Spatially resolved Raman spectroscopy, SEM, and synchrotron X-ray diffraction were used to monitor the self-organization of the particles inside the cellulosic scaffold. Structure coordinated assemblies of nanoparticles could enable novel and widespread applications of these composite materials depending on the function imparted by the nanoparticle system of choice.
Session VIII : Alexander Bittner
Authors : Massimo Morbidelli
Affiliations : Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Z?rich, CH-8093 Z?rich, Switzerland
Resume : Emulsion polymerization is a well developed technology which allows producing polymer colloids or nanoparticle with highly controlled size and polydispersity, in a variety of different chemical composition and with well controlled morphology. Typically, after the polymerization reactors latexes are coagulated into powders again using consolidated processes. Recent results in the theory of colloidal systems indicated the possibility to exploit these aggregation and breakage events under controlled conditions to produce macrostructures which are other ways not realizable. For example one can mix dispersions of different composition and realize composites with a well controlled dispersion of one phase into the other. By controlling the gelation process one can create inside such composites percolating phases which allow transporting at the macroscopic scale properties exhibited by colloids only at the nanoscale. Examples of different structured materials of interest in various application fields are discussed. These include the production of controlled porous materials in the form of micro-particles or monoliths, which can be used as adsorbents for large (bio) molecules or as thermal insulators. Other areas of interest include drug delivery and enhanced oil recovery.
Authors : M. Ibáñez1,2, O. Drobozhan,3 G. Nedelcu, 1,2 A. Cabot3,4, M. Kovalenko1,2
Affiliations : 1 Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093, Switzerland 2 Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland 3Catalonia Institute for Energy Research IREC, 08930 Sant Adrià de Besòs, Barcelona, Spain 4 Institució Catalana de Recerca i Estudis Avançats ICREA, 08010 Barcelona, Spain
Resume : In the last decade the field of thermoelectrics had seen many advances, originating largely from the engineering of suitable nanostructured materials. So far the dominating strategies for producing bulk thermoelectric nanomaterials are grinding and precipitation of secondary phases in metastable solid solutions. Both approaches have limited control over the distribution of phases at the nanoscale and/or lack compositional versatility. Another powerful strategy can be devised from the bottom-up assembly and consolidation of colloidal nanoparticles (NPs) into bulk-like materials. Such approach is virtually unlimited in terms of compositional variety and dimensionality of constitutents. Efficient and predictable electronic doping remains a key challenge for maximizing carrier density (deliberately for holes or electrons). At nanoscale, conventional substitutional atomic doping can be supplemented with the mesoscale doping - carrier donation between individual NPs. Here we demonstrate that through the engineering of nanocomposites by simple co-assembly of various NP building blocks the charge carrier concentration can be enhanced via mutual doping, while preserving low thermal conductivities and high Seebeck coefficients, thereby increasing the overall thermoelectric figure of merit.
Authors : Fabiane J. Trindade, Liliam Y. Kaori, Jiale Wang, Clara J. Rangel, Rômulo A. Ando and Pedro H. C. Camargo*
Affiliations : Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, Av. Lineu Prestes, 748, 05508-000 São Paulo, SP, Brazil. *Corresponding author: E-mail: email@example.com
Resume : In this work, we report on a facile and strategy for the synthesis of hexagonal palladium (Pd) nanoplates having controlled sizes in the 40 to 90 nm range employing water as the solvent, polyvinylpyrrolidone (PVP) as both the reducing agent and the stabilizer, and 100 oC as the temperature. Interestingly, we found that the size of the produced nanoplates could be precisely adjusted by varying the molecular weight of PVP molecules employed during the synthesis. Moreover, for a fixed PVP molecular weight, the size of the Pd nanoplates could also be controlled by changing the growth time. The morphological evolution as a function of time was investigated and supported the kinetically controlled growth mechanism for the generation of Pd nanoplates. The nanoplates could also be employed as templates for gold (Au) deposition in order to produce bimetallic Pd-Au nanoplates, which are interesting for applications in Surface Enhanced Raman Scattering detection. In this case, we could obtain both core-shell Pd-Au nanoplates and Pd nanoplates decorated with Au nanoparticles by controlling the experimental parameters during the Au deposition step. We believe our results provide new insights on the synthesis of monodisperse Pd nanoplates and bimetallic Pd-Au nanoplates with high yields as well as controlled sizes and architectures.
Poster Session : Andreu Cabot
Authors : Santanu Jana, Patrick Davidson, Benjamin Abécassis
Affiliations : Laboratoire de Physique des Solides, Univ. Paris-Sud, CNRS, UMR 8502, F-91405 Orsay Cedex, France
Resume : Colloidal nanoplatelets (NPLs), which are also known as colloidal quantum wells, are light emitting materials exhibiting unique optical properties making them promising for light emitting diodes and lasers.1,2 These properties include narrow photoluminescence full-width at half-maximum (~8 nm) and absence of inhomogeneous broadening.3 Recently, NPLs have been found to assemble into micrometers long anisotropic needle-like super-particles by addition of anti-solvent to a stable colloidal solution.4 Interestingly, these anisotropic large particles display polarized light emission. In this work, we present face to face self-assembly of two dimensional thin CdSe nanoplatelets into one dimensional micrometer length anisotropic CdSe threads-like networks. We demonstrate a facile strategy for assembling 2D square quantum wells into 1D micrometer length thread-like structures consisting of repeated and fixed gaps along the longitudinal direction. These structures are flexible since they are composed of a single platelet in their lateral dimension and continuously break and reform in solution similar to living polymers formed by some surfactants. Fine-tuning of the length of these nanoparticle polymers is achieved by varying the experimental conditions. Interestingly, their formation is a non-equilibrium process and once formed, they can be manipulated and redispersed in solution while keeping their very bright emission. Optical fluorescence microscopy, transmission electron microscopy provide detailed structural characterization and show that threads can be composed by highly organized 100 to 1000 nanoplatelets. Small-angle X-ray scattering of CdSe threads in solution shows a strong peak at wave vector q=1.23 nm-1 corresponding to the 001 stacking reflection with period 5.1 nm which is center to center distances of two nearest platelets in CdSe threads. References: (1) Ithurria, S.; Dubertret, B. JACS 2008, 130, 16504. (2) Lhuillier, E.; Pedetti, S.; Ithurria, S.; Nadal, B.; Heuclin, H.; Dubertret, B. Acc. Chem. Res. 2015, 48, 22. (3) Tessier, M. D.; Javaux, C.; Maksimovic, I.; Loriette, V.; Dubertret, B. ACS nano 2012, 6, 6751. (4)Abecassis, B.; Tessier, M. D.; Davidson, P.; Dubertret, B. Nano lett. 2014, 14, 710.
Authors : S. Ortega (1), D. Cadavid (1), Y. Liu (1), M. Ibáñez (2,3), A. Cabot (1,4)
Affiliations : 1 Catalonia Institute for Energy Research IREC, 08930 Sant Adrià de Besòs, Barcelona, Spain 2 Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093, Switzerland 3 Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, CH-8600, Switzerland 4 Institució Catalana de Recerca i Estudis Avançats ICREA, 08010 Barcelona, Spain
Resume : The design and engineering of nanomaterials by the bottom-up assembly of solution-processed nanocrystal building blocks opens up countless opportunities to produce metamaterials with controlled functional properties. Furthermore, solution-based thin film deposition methods are particularly interesting as they promise lower manufacturing costs, and open the door to new routes for the design of flexible solid-state thermoelectric devices  that can play a big role on remote power or personal devices, i.e. wearables. In this work, we detail the preparation of bulk thermoelectric nanocomposites from the bottom-up assembly of solution-processed nanocrystals. Taking advantage of the versatility [2,3] of this technique, we engineer nanocomposites by simple assembly of precisely designed nanocrystal building blocks. We will prove that this methodology provides the necessary level of compositional and morphological control to produce high performance thermoelectric materials. In addition, we have step forward into the preparation of a flexible thermoelectric device based on the solution-processed material developed. References:  Z. Lu, M. Layani, X. Zhao, L. P. Tan, T. Sun, S. Fan, Q. Yan, S. Magdassi, H. H. Hng, Fabrication of flexible thermoelectric thin film devices by inkjet printing, Small, 10 (17), 3551-3554 (2014).  D. Cadavid, M. Ibáñez, S. Gorsse, A. M. López, J. R. Morante, A. Cabot, Bottom-up processing of thermoelectric nanocomposites from colloidal nanocrystal building blocks: the case of Ag2Te-PbTe, J. Nanopart. Res., 14, 1328 (2012).  M. Ibáñez, R. Zamani, S. Gorsse, J. Fan, S. Ortega, D. Cadavid, J. R. Morante, J. Arbiol, and A. Cabot, Core-Shell Nanoparticles As Building Blocks for the Bottom-Up Production of Functional Nanocomposites: PbTe_PbS Thermoelectric properties, ACS Nano, 7 (3), 2573-2586 (2013).
Authors : A.Zitouni, S.Bentata, B.Bouadjemi, T.Lantri, W. Benstaali, Z.Aziz, S.Cherid
Affiliations : aLaboratory of Technology and of Solids Properties, Faculty of Sciences and Technology, BP227 Abdelhamid Ibn Badis University, 27000 Mostaganem, Algeria
Resume : we investigate the structural, electronic and magnetic properties of the diluted magnetic semiconductors (DMSs) CdCoTe and CdMnTe in the zinc blende phase with 25% of Co and Mn. The calculations are performed by the recent ab initio full potential augmented plane waves (FP_L/APW) method within the spin polarized density-functional theory (DFT) and the generalized gradient approximation GGA. Structural properties are determined from the total energy calculations and we found that these compounds are stable in the ferromagnetic phase. We discuss the electronic structures, total and partial densities of states and total magnetic moments. The calculated densities of states presented in this study identify the half-metallic of CdCoTe and CdMnTe.
Authors : D. Drude, K. Brassat, Ch. Brodehl, J.K.N. Lindner
Affiliations : Dept. of Physics, University of Paderborn, Paderborn, Germany; Center for Optoelectronics and Photonics Paderborn CeOPP, Paderborn, Germany
Resume : Nanosphere lithography is an established technique for the formation of ordered nanoparticles on large areas at low cost. Hexagonally self-arranged mono- or bilayers of colloidal nanospheres act as a shadow mask for subsequent site-controlled surface modifications such as material deposition, leaving a periodic array of nanoparticles. The hexagonal order as well as defects of the sphere mask are directly transferred to the nanoparticle pattern. We use the doctor blade technique based on a convective self-assembly process to form hexagonal monolayers of polystyrene beads from an aqueous suspension on silicon surfaces. The particles arrange themselves at the triple-phase boundary between suspension, solid substrate and surrounding gas phase. This process depends on several experimental parameters such as the relative humidity, substrate temperature, particle concentration, particle size distribution and blade velocity. We investigate the influence of these parameters on the formation of typical defects in the monolayer such as voids, quadratic arrangements, grain boundaries and other inhomogeneities. Optical and scanning electron microscope images are analyzed by a new algorithm based on Delaunay triangulation and defect densities are calculated. We show, that the densities of different defect types correlate directly with the experimental parameters. This allows to minimize selected defect densities by adjusting experimental conditions during the self-assembly process.
Authors : O. Ivanyuta, Yu. Pogrebnyak
Affiliations : Department Electrophysics, Faculty of Radiophysics, Taras Shevchenko National University of Kyiv
Resume : The concept to these building blocks optical activity in biosurrounding is based on developed model for a photoresponse of metal-organic complex on carbon nanotube, which has bond with modified by organic molecule ends and/or walls CNT. Such complex for using carbon nanosystems organization is a favorable tools for designing and synthesis of new hybrid carbon nanosystems as templates for biomolecules attaching and their biocompatibility and photoactivity. Functionalized carbon nanotubes (CNTs), having multifunctional application both as separated and as building blocks in cluster-assembled nanosystems and the method to functionalize CNTs with metal-organic complexes, which are linked the СNTs by covalent bonds with possible bonding biomolecules, with novel functionalization of CNTs by aminoderevatives, that support formation of metal-organic complex on carbon nanotube as building blocks.
Authors : C. Spaas, R. Dok, O. Deschaume, C. Bartic, P. Hoet, F. Van den Heuvel, J.P. Locquet, S. Nuyts, C. Van Haesendonck
Affiliations : KU Leuven, Department of Physics and Astronomy KU Leuven, Department of Oncology KU Leuven, Department of Public Health and Primary Care, Environment and Health University of Oxford, CRUK/MRC Institute for Radiation Oncology and Biology
Resume : With as main prospective the localized eradication of malignant cells, the radiosensitization of gold nanoparticles is most effective in close proximity to the cellular DNA. However, the preservation of colloidal stability and the implementation of specific cell targeting requires a supplementary organic coating grafted on the gold nanoparticle surface. The latter consisting of functionalizing polymers and antibodies, necessary for the internalization to the nucleus, attenuates the irradiation dose enhancement caused by the GNPs. The influence of the nanoparticle capping layer thickness, build up with PEG polymers of MW 1 to 20 kDa, on the radiosensitizing effect of GNPs is demonstrated by evaluation of the relaxation pattern of supercoiled DNA. Image analysis of gel electrophoresis and subsequent quantification conclude that on average 58% of the radiosensitizing efficiency is lost when the radial dimensions of the functionalizing layer are increased from 4.1 to 15.3 nm. An experimental supplement is thereby provided for biophysical simulations and demonstrates the influence of an important parameter in the development of nanomaterials for targeted therapies in cancer radiotherapy. Alongside the PEG functionalization, supplementary antibodies are then introduced to create cell specific interactions. Maximal affinity and stability of the nanocomplex is created and proposed for further experimental research on the radiosensitization performances of gold nanoparticles.
Authors : G. Joshua1, P. Guardia,1,2 D. Cadavid1, A. Cabot 1,3
Affiliations : 1) Catalonia Energy Research Institute - IREC, 08930 Sant Adrià del Besos, Barcelona, Spain 2) Centre Tecnològic de la Química de Catalunya - CTQC, 43007 Tarragona, Spain 3) Institució Catalana de Recerca i Estudis Avançats ICREA, Barcelona, Spain
Resume : The colloidal synthesis of thermoelectric nanoparticles (NPs) has been proposed as an alternative to the current methods used for thermoelectric applications. Recently, an increase in the ZT value has been reported when using PbSe/PbTe core/shell NPs. This approach has a strong limitation since their synthesis is a non-trivial issue limited to a few materials. Nanoparticle clusters (NPCs) produced from the assembly of different NPs clearly overcomes this limitation and offers a versatile tool to produce a large range of nanocomposites for thermoelectric applications. In this regard, lead chalcogenides NPs syntheses offer the possibility to produce particles with control over size and shape in a large scale. Assembling different lead chalcogenide NPs into NPCs will allow for the control of composition and segregation over a large area. Here we compare two different cluster procedures to produce PbS-PbSe and PbSe-PbTe NPCs for thermoelectric applications. While one approach exploits quaternary ammonium salts (CTAB and DTAB) as mediators for the NPs assembly, the other is based on the destabilization of nano-micelles in the presence of ethyleneglycol and polyvinylpyrrolidone. Our results show that the use of different procedures exploiting ionic or non-ionic molecules has a strong influence on the final NPCs composition and in the final ZT value. As a conclusion post-synthesis procedures, even at mild conditions, could strongly influence the final NPCs performance. The results reported here provide a first understanding of how NPCs could boost the current NPs technology.
Authors : B. Kalska-Szostko*, U.Wykowska*, B. Piotrowska*, D. Satuła#
Affiliations : * Institute of Chemistry, University of Bialystok, Hurtowa 1, 15-399 Białystok, Poland #Department of Physics, University of Bialystok, Ciolkowskiego 1L, 15-245 Białystok, Poland
Resume : Today, preparation of 0D well-defined nanoparticles which represents inert structure divided on core and shell have obtained extensive interest among scientist. The reason of such popularity of low dimensional structures is that the core-shell nanoparticles have many interesting optical, magnetic, electrical, and mechanical properties which can be combined in one species  in contrast to single element particles. In presented paper, core-shell ferrite nanoparticles, with various composition of the core were prepared. Presented nanoparticles, has a core obtained from a mixture of Fe3+, Fe2+ and Men+ ions (where Me = Co2+, Co3+, Mn2+, Mn3+ or Ni2+), in such way, to preserve crystalline structure of magnetite. Then the magnetite shell layer was added, to obtain core-shell structure. Seeds of nanoparticles were fabricated from the proper metal acetylacetonate salts in diphenyl ether, oleic acid and oleyl amine environment. Characterization of the nanoparticles was done by Transmission Electron Microscopy, X-ray diffraction, Infrared spectroscopy, and Mössbauer spectroscopy.  Y. Zhu, H. Da, X. Yang, Y. Hu, Colloids and Surfaces A: Physicochem. Eng. Aspects 231 (2003) 123-129
Authors : Cezary Czosnek 1a*, Mariusz Drygaś 1a, Jerzy F. Janik 1a, Mirosław M. Bućko 1b, Zbigniew Olejniczak 2
Affiliations : 1 AGH University of Science and Technology, aFaculty of Energy and Fuels, b Faculty of Materials Science and Ceramics; al. Mickiewicza 30, 30-059 Krakow, Poland 2 Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, 31-342 Krakow, Poland *firstname.lastname@example.org
Resume : Silicon carbide SiC has many advantageous properties including the high thermal, mechanical, and chemical stabilities, relatively low density, and semiconducting properties. In this regard, the high thermal conductivity makes this material a valuable catalyst support for exothermic reactions, for instance, in reacting carbon monoxide and hydrogen towards methane. Herein, presented is a study on the effect of temperature of the first aerosol-assisted stage on silicon carbide crystallization during the second stage temperature treatment of the bulk raw powder. Nanocrystalline SiC was prepared from aerosolized hexamethyldisiloxane at 1200 and 1400 C followed by a second stage pyrolysis under argon at 1650 C. Additionally, the sample obtained in the first aerosol-assisted stage at 1400 C was thermally treated in bulk at the same temperature for 1 hour under argon. The as-prepared products were characterized by powder XRD, SEM, solid state 29Si MAS NMR, and FT-IR spectroscopy. The data clearly confirmed the impact of the temperature treatment on the kind of polytype(s) and average crystallite size of the resulting nano-SiC. Acknowledgment. This work was supported by AGH University of Science and Technology Grant No. 220.127.116.11.
Authors : Dániel ZÁMBÓ, Szilárd POTHORSZKY, András DEÁK
Affiliations : Institute for Technical Physics and Materials Science, HAS Centre for Energy Research, P.O. Box 49, H-1525 Budapest, Hungary
Resume : In this study we report about the controlled clustering of gold nanoparticles, which were grafted by low molecular weight (2000 Da) α-methoxy-ω-amino poly(ethylene glycol) (amino-PEG) molecules. Low molecular weight amino-PEG can be used not only as a stabilizer, but also as a thermoresponsive surface coating. The PEG molecules were immobilized to the gold nanoparticles surface by amino-Au bond [1,2], which resulted nanoparticles with high stability in water and in organic solvents as well. Additionally, the particles remained stable at high temperature in water, but the system can be destabilized using inert electrolyte (K2SO4) and high temperature. The reason for this is the lowering of the lower critical solution temperature (LCST) of the PEG, which is originally above 100°C, but can be decreased in high ionic strengths . The triggered clustering of gold nanoparticles can be followed by time-resolved spectroscopy and dynamic light scattering techniques in order to investigate the evolution of the nanoparticle cluster formation. The structure of the nanoparticle clusters was investigated by FE-SEM after the aggregation process. The results show that the kinetics of clustering for gold nanoparticles can be controlled through two main parameters: the ionic strength and the temperature of the system. Acknowledgment This work received funding from the European Union s Seventh Framework Programme for research, technological development and demonstration under Grant N° 310250. The project was supported by the Hungarian Scientific Research Fund OTKA-PD-105173 and K-112114. A.D. acknowledges the support of the Janos Bolyai Research Fellowship from the Hungarian Academy of Sciences. D.Z. and Sz.P. acknowledges the support of the Pro Progressio Foundation and Jozsef Varga Foundation.  Leff, D. V., Brandt, L. & Heath, J. R. Synthesis and Characterization of Hydrophobic, Organically-Soluble Gold Nanocrystals Functionalized with Primary Amines. Langmuir 12, 47234730 (1996).  Kumar, A., Mandal, S., Pasricha, R., Mandale, A. B. & Sastry, M. Investigation into the Interaction between Surface-Bound Alkylamines and Gold Nanoparticles. Langmuir 19, 62776282 (2003).  Zámbó, D., Radnóczi, G. Z. & Deák, A. Preparation of Compact Nanoparticle Clusters from Polyethylene Glycol-Coated Gold Nanoparticles by Fine-Tuning Colloidal Interactions. Langmuir 31, 26622668 (2015).
Authors : Szilárd Pothorszky, Dániel Zámbó, András Deák
Affiliations : Institute for Technical Physics and Materials Science, HAS Centre for Energy Research, P.O. Box 49, H-1525 Budapest, Hungary
Resume : Assembly of plasmonic nanoparticles rely on colloidal interactions including eletrostatic-, van der Waals, molecular dipole, and many other different forces.1 The collective properties of assembled particles depend on size, shape and their relative orientation. By using gold nanorods (AuNRs) its intrinsic shape-anisotropy gives the opportunity for anisotropic assembly, which can be exploited in a number of important applications,, like surface-enhanced Raman scattering (SERS)2 or nanoparticle networks3. Here, we report a novel strategy to assemble gold nanoparticles (AuNPs) in an orientation-controlled way based on colloidal interactions. By means of regio-selective surface modification of AuNRs we succesfully achieved a robust system in which only the tips of the nanorods are preferable for spherical particles independently from their concentration. The assembly of the rod and spherical nanoparticles was carried out in the bulk and followed by means of VIS spectroscopy. The assembled structures were investigated by SEM. The approach of site-selective surface modification is based on taking advantage of the slightly anisotropic coverage of AuNRs by the CTAB bilayer. The nanorod tips were functionalized with a well defined amount of charged thiol molecules without stripping the side face. In a second step the sides of the NRs were covered by mPEG-SH which acts as a stabilizer against NR aggregation and inhibitor for side-adsorption of spherical nanoparticles, hence the spherical nanoparticles adsorb mainly at the tips of the NRs. As the size of the spherical particles increases, the side adsorption gets more preferred, independently of the site selective surface modification of the NRs. ACKNOWLEDGEMENTS This work received funding from the European Unions Seventh Framework Programme for research, technological development and demonstration under Grant N° 310250. The project was supported by the Hungarian Scientific Research Fund OTKA-PD-105173 and K-112114. A.D. acknowledges the support of the János Bolyai Research Fellowship from the Hungarian Academy of Sciences. SZ.P. and D.Z. acknowledges the support of the Pro Progressio Foundation and József Varga Foundation. REFERENCES 1. Bishop, K. J.; Wilmer, C. E.; Soh, S.; Grzybowski, B. A. Nanoscale Forces and Their Uses in Self-Assembly. Small 2009, 5, 16001630. 2. Zhong, L. et al. Rational design and SERS properties of side-by-side, end-to-end and end-to-side assemblies of Au nanorods. Journal of Materials Chemistry 21, 14448 (2011). 3. Sanchot, A. et al. Plasmonic Nanoparticle Networks for Light and Heat Concentration. ACS Nano 6, 34343440 (2012).
Authors : Doruk Ergöçmen,1,2* Habeeb Muhammed Madathumpady Abubaker,1,2 Adam J. Blanch,1,2 José Hierrezuelo,3 Dermot Brougham3 and Jessica Rodríguez-Fernández1,2
Affiliations : 1Department of Physics and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Munich (Germany) 2Nanosystems Initiative Munich (NIM), Munich (Germany) 3School of Chemical Sciences, Dublin City University (Ireland)
Resume : In the last several years extensive research has been carried out on vacancy-doped plasmonic semiconductor nanoparticles with tunable localized surface plasmon resonances (LSPRs) in the near-infrared (NIR) region. Unlike noble metal nanoparticles, the LSPRs of vacancy-doped copper chalcogenide nanocrystals originate from the collective oscillation of holes, and they feature the possibility to turn on and off their plasmonic and excitonic properties by chemical means. Combining the intrinsic properties of magnetic- or noble metal nanoparticles with the optoelectronic properties of vacancy-doped plasmonic semiconductors into a well-defined colloidal assembly is of importance to enable the investigation of phenomena arising from the controlled interaction of the different building-blocks. In this work we will present our latest results on hierarchical hybrid assemblies comprising a magnetic or metal nanoparticle core and a plasmonic semiconductor shell made out of Cu2-xSe supraparticles (SPs). We will discuss the experimental requirements needed to obtain such assemblies and the properties stemming from them. References:  Joseph M. Luther, Prashant K. Jain, Trevor Ewers and A. Paul Alivisatos Nat. Mater. 2011 (10), pp 361-366  Ilka Kriegel, Chengyang Jiang, Jessica Rodríguez-Fernández, Richard D. Schaller, Dmitri V. Talapin, Enrico da Como, and Jochen Feldmann J. Am. Chem. Soc. 2012, (134), pp 1583-1590.
Authors : F. Mohamed, M. Corva, E. Vesselli, M. Peressi
Affiliations : University of Trieste, Department of Physics, Trieste (Italy)
Resume : For most practical applications, metal nanoparticles (NPs) need to be supported on a substrate that can act as a deposition template for the growth of regular arrays and is relevant in preventing sintering at high temperatures, a process that would deactivate the catalytic devices. The Moire pattern due to the small lattice mismatch between graphene and Ir(111) could be an efficient template for an ordered array of metal NPs. With the help of ab-initio calculations we compare the behaviour of different metals, with the aim of finding those more suitabile for an ordered growth. The role of a possible seed is also discussed.
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Session IX : Beatriz Hernandez-Juarez
Authors : Maryna I. Bodnarchuk, Sergii Yakunin, Maksym. V. Kovalenko
Affiliations : ETH Zürich, Department of Chemistry and Applied Biosciences, CH-8093, Zurich, Switzerland and Empa-Swiss Federal Laboratories for Materials Science and Technology, CH-8600, Dübendorf, Switzerland
Resume : Colloidal metallic and semiconductor nanocrystals (NCs), functionalized with inorganic capping ligands such as metal chalcogenide complexes (MCCs), have recently emerged as versatile optoelectronic materials for applications in photovoltaics, photodetectors, thermoelectrics, and field-effect transistors. As-prepared MCC-capped NCs are highly charged and dispersible only in polar solvents, and lack the ability to spontaneously form long-range ordered NC superlattices. Here we present a simple and general methodology, based on host-guest coordination of MCC-capped NCs with macrocyclic ethers (crown ethers and cryptands), enabling the solubilization of inorganic-capped NCs in solvents of any polarity and improving the ability to form NC superlattices. The corona of organic molecules can also serve as a convenient knob for the fine adjustment of charge transport in films of NCs, as demonstrated here for the photoconductive properties of PbS NCs. In particular, high infrared photon detectivities of 3.3·10e11 Jones with a fast response (3 dB cut-off at 3 kHz) at 1200 nm were obtained for a photoconductor based on PbS/K3AsS4/decyl-18-crown-6 films. At the same time, films of crown-free PbS/K3AsS4 NCs are too conductive to observe efficient photocurrent generation, while initial oleate-capped PbS NCs are fully insulating.
Session V : Andrey Rogach
Authors : Stefano Sacanna
Affiliations : New York University
Resume : Shape and chemical anisotropy play fundamental roles at the colloidal scale, as they can govern the autonomous organization of particles into precise hierarchical structures and ultimately into a desired new material. In this talk, I will present an emulsion-based methodology to design and mass-produce building blocks featuring anisotropic shapes and interactions. The method is based on chemically reactive emulsion droplets that can be polymerized, reshaped and functionalized in bulk. I will further highlight how we use these building blocks to develop heuristic rules to create self-assembling colloidal systems.
Authors : Thomas Altantzis1, Daniele Zanaga1, Bart Goris1, Ana Sánchez-Iglesias2, Marek Grzelczak2&3, Luis M. Liz-Marzán2&3, Gustaaf Van Tendeloo1, Sara Bals1
Affiliations : 1. EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium 2. Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia San Sebastián, Spain 3. Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
Resume : Assemblies of metallic nanoparticles have gained increasing interest during the last years, due to their multiple applications and improved properties, compared to those of their building blocks. By modifying different experimental parameters such as the size and the shape of the individual nanoparticles, as well as their in-between distances, assemblies with various shapes and functionalities can be obtained.(A. Sanchez-Iglesias, 2012) In order to gain better insight concerning the structure and the shape of those configurations which are inseparably connected to their characteristic properties and applications, a detailed structural and morphological characterization is of utmost importance. Transmission Electron Microscopy has been proved to be an ideal technique to investigate materials at both the nanometer and atomic scale and has therefore been widely used in the study of nanomaterials. However, TEM images only correspond to a two-dimensional (2D) projection of a three-dimensional (3D) object. In order to gain the necessary structural information concerning the 3D nanoassemblies, electron tomography has to be performed.(T. Altantzis, 2013) By applying the technique at the different case studies, we were not able to get only qualitative information, but also quantitative information such as number of particles in each assembly, inter-particle distances and coordinates of the nanoparticles in the system, which could be later used for a more detailed theoretical study.
Authors : Michael Carlson, Dermot Brougham, Jacek Stolarczyk
Affiliations : Department of Physics and Center for NanoScience (CENS), Ludwig-Maximilians-Universität München, Munich, Germany; Chemical Sciences Department, Dublin City University, Dublin, Ireland
Resume : Multicomponent nanomaterials have received much attention recently due to their myriad of types and burgeoning potential applications. We present one such multicomponent system cadmium sulfide nanorods decorated with magnetic nanoparticles at the tips. With the introduction of the magnetic tips and the novel utilization of NMR techniques, the collective behavior and charge transfer from the magnetically tipped nanorods to the electron acceptors in solution can be discerned and characterized in an aqueous environment. Typically used for photocatalytic reactions, the interplay of these multifunctional heterostructures with each other, along with their surrounding medium, can provide further insights into energy conversion and the time-scales of its attendant processes.
Session X : Maksym Kovalenko
Authors : Bartosz A. Grzybowski, FRSC
Affiliations : UNIST and IBS Center for Soft and Living Matter
Resume : Nanoscopic objects stabilized with charged organics exhibit properties fundamentally different from either molecular or macromoleculer ions, and can combine ionic-like properties with electronic and ionic conductivity and/or photoexcitability. By careful control of electrostatic interactions, nanoions of various shapes and material compositions can be assembled into functional nanomaterials including 3D supracrystals, layered crystals, or extended films. Depending on the properties of the charged organics, these nanomaterials can act as chemical amplifiers, photoconductors, diodes, transistors, or even full-fledged electronic circuits containing no semiconductors. This last set of constructs can integrate on the nanoparticles electronic function with chemical sensing.
Authors : Ajay Singh 1, 2, Amita Singh 1,2, Gary Ong 1,2, Dennis Nordlund 3, Karen Bustillo 1, Jim Ciston 1, Delia J. Milliron 2.
Affiliations : 1. The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA 2. McKetta Department of Chemical Engineering, The University of Texas at Austin, Texas 78712, USA 3 Stanford Synchrotron Radiation Lightsource, Stanford, California, 94309, USA
Resume : Self and directed assembly of nanorods into ordered superstructures is an area of intense research interest as in such architectures, the discrete size defined properties of each nanostructure can be collectively harnessed at a scale amenable to real application. The formation of vertically aligned nanorods into hexagonal superlattices is a recent development leading to structured arrays suited for high-density applications. Spontaneous supercrystal organization in nanorods requires low polydispersity in both diameter and length, which can complicate the assembly compared to that of spherical nanocrystals. These nanorods can be pre-assembled as 2D sheets during synthesis by incorporating certain amount of foreign ion or dopant in the nanorod structure. Further, dispersed solution containing 2D sheets can be deposited in any substrate by either spin coating or drop casting to form thin film of micrometre-sized super lattice. In this work, we focus on understanding how dopant incorporation on the nanorod modifies their surface chemistry to from vertically aligned nanorods superstructure (2D sheets) in solution. We show by using synchrotron small-angle x-ray scattering (GIXAS) and dynamic light scattering, that optimum concentration of dopant is required to tune the nanorod-nanorod interaction (repulsive and attractive) in solution to nucleate the self-assembly process. These 2D sheets of nanorods were extensively studied by GIXAS, XPS, HRSTEM, HRSEM and SAED.
Authors : Michaela Meyns (1), Pablo Guardia (2), Gihan Joshua (1), Andreu Cabot (1,3)
Affiliations : (1) Catalonia Energy Research Institute (IREC), 08930 Barcelona, Spain; (2) Centre Tecnol?gic de la Qu?mica de Catalunya, 43007 Tarragona, Spain; (3) Instituci? Catalana de Recerca i Estudis Avancats (ICREA), 08010 Barcelona, Spain.
Resume : Self-assembly of nanoparticles has led to a fascinating variety of accessible well-defined super structures. Of particular interest is the assembly of binary nanoparticle arrays with complementary or synergistic properties. The electrostatic assembly of oppositely charged nanoparticles offers the possibility of a high degree of control and increased variety of accessible superstructures such as diamond-like Au-Ag supercrystals compared to van-der-Waals driven processes [Kalsin et al. Science 2006, 312, 420]. There is number of strategies to achieve sufficient charging of nanoparticles, from atomic to polymeric ligands, from aqueous synthesis to ligand exchange. A critical point in the assembly process is the colloidal stability of the charged particles. Different strategies for charging nanoparticles and their implications on colloidal stability and for the later assembly will be discussed with an emphasis on post-synthetic ligand exchange and binary semiconductor-metal systems.
Authors : F. Laatar (1), M. Hassen (1,2), and H. Ezzaouia (1)
Affiliations : (1) Photovoltaic Laboratory, Centre for Research and Technology Energy, Tourist Route Soliman, BP 95, 2050 Hammam-Lif, Tunisia (2) Higher Institute of Applied Science and Technology of Sousse, City Taffala (Ibn Khaldun), 4003 Sousse Tunisia
Resume : Cadmium selenide quantum dots (CdSe QDs) solution containing L-cysteine (L-Cys) was deposited onto glass substrates by spin-coating method at different temperatures. The influence of the solution temperature (TSol) beginning at 30°C upto 80°C on the crystallographic structure, morphology as well as optical properties of the films was studied in detail. XRD analysis reveal that the obtained CdSe films have a cubic structure with a crystalline orientation along (111) plane, and show that the produced film at 80°C has a better crystalline quality and highest size of CdSe QDs (3.62 nm). XRD data of CdSe thin films were used to calculate the structural parameters such as crystallite size, strain, and dislocation density. The reflection peaks (111), (220), and (311) were used to reveal the nanocrystallite sizes and lattice strains, using the model of Halder-Wagner. The lattice parameters for CdSe thin films were estimated from Nelson Riley plot. The evolution of the surface morphology was studied by atomic force microscopy (AFM). Optical properties were investigated by UVVis spectrophotometer and photoluminescence spectrometer. The optical transmittance decreased with the increase of solution temperature (or the increase of film thickness). The optical band gap value decreased from 2.37 to 2.25 eV as the solution temperature increased. Increasing TSol promotes the increase in the crystallite size and improves the crystallinity of deposited films.
Session XI : Ajay Singh
Authors : Maria Acebrón, Héctor Rodríguez-Rodríguez, J. Ricardo Arias-González and Beatriz H. Juárez
Affiliations : Universidad Autónoma de Madrid, Spain
Resume : SiO2 encapsulation of alloyed CdSeZnS nanocrystals (NCs) shows differences in terms of optical properties and luminescence quantum yield, depending on the surface composition, size, and ligand content. In this work, emphasis has been placed on the fine control required to obtain luminescent SiO2 encapsulated NCs by studying the role of oleic acid (OA), stearic acid (SA), and dodecanethiol (DDT) ligands on the alloyed NCs. While the use of anchored DDT molecules is essential to preserve the optical properties, intercalated OA and SA play a critical role for SiO2 nucleation, as stated by 1H NMR (including DOSY and NOESY) spectroscopy. (1). Furthermore, optical trapping (2,3) of these encapsulated NCs allows for their individual manipulation and acquisition of their optical properties and evolution in solution. Surface effects generated by the laser beams composing the optical tweezer and the surrounding medium will be discussed. These results emphasize the importance of surface chemistry in semiconducting NCs.
Authors : Alessandro Lauria, Irene Villa, Andreas Braendle, Mauro Fasoli, Walter Caseri, Anna Vedda, Markus Niederberger
Affiliations : Laboratory for Multifunctional Materials, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland Department of Materials Science, University of Milano-Bicocca, Via R. Cozzi 55, 20125 Milano, Italy
Resume : The employment of nanoparticles in optical applications is an ideal strategy for minimizing the light scattering associated with the discrete form of the material. The control over structure and emission maxima is crucial in order to tailor materials for the final application. Hafnium dioxide is a wide band-gap semiconductor with outstanding thermal stability, remarkable chemical inertness, high density, and UV-visible transparency. We report a strategy for the production of nearly spherical HfO2 nano-dots obtained by nonaqueous sol-gel where the multifunctional role of rare earth doping is evidenced. On one hand, rare earth dopant ions activate the visible luminescence of the nanocrystals. On the other hand the incorporation of trivalent ions is shown to be suitable for the room temperature stabilization of the cubic polymorph of HfO2, with potentially great benefits in the realization of new polycrystalline optical ceramics for scintillator applications with reduced birefringence. We incorporated the colloids into trasparent hosts such as polymers and oxides, obtaining luminescent composites where the processability of the host and the outstanding photostability of inorganic nano-phosphors are merged together. These systems might be suitable for new low-cost/solution-processed radiation detectors and scintillators, and for luminescent solar concentrators expressly designed for the photoconversion in harsh conditions of high energy radiation, from the UV to the X-rays rang
Authors : Wei Cheng, Markus Niederberger
Affiliations : Laboratory for Multifunctional Materials, Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 5, 8093 Zurich (Switzerland)
Resume : Alignment of metal oxide nanowires over a large area is a prerequisite to use their collective properties in devices. As n-type semiconductors, tungsten oxides (WO3-x) have promising applications in gas sensors, photodetector, electrochromic devices, or as photocatalysts. Ultrathin (diameter less than 10 nm) tungsten oxide nanorods and nanowires have already been synthesized and assembled for electrochromic applications. However, up to now, no successful attempts to align them on a large scale for gas sensing or photodetecting applications have been reported. We have recently developed a facile solution method for the synthesis of colloidally stable single crystalline ultrathin W18O49 nanowires, with diameters of about 1.7 nm and aspect ratios larger than 100. By Langmuir-Blodgett technique, the flexible ultrathin nanowires can be successfully oriented over a large scale and transferred to Si/SiO2 substrates patterned with Pt interdigitated electrodes. This technique allows us to obtain aligned nanowires thin films with desired number of layers. The aligned W18O49 nanowire thin films exhibit excellent sensing performance towards hydrogen in humid air, at room temperature, indicating their high potential for gas sensors. Moreover, we found these nanowires can also be aligned over a large area of a flat or patterned substrate by a simple self-assembly method. The self-assembled nanowire thin films show outstanding sensitivity and stability to ultraviolet light, indicating their potential for optoelectronic applications. The strategies developed here represents two of the few examples, where nanoscale building blocks are successfully integrated in a macroscopic device.  W. Cheng, Y. Ju, P. Payamyar, D. Primc, J. Rao, C. Willa, D. Koziej, M. Niederberger, Angew. Chem. Int. Ed. 2015, 54, 340-344.  W. Cheng, M. Niederberger, Self-assembly of ultrathin tungsten oxide nanowires on patterned substrates for ultraviolet photodetector. In preparation (2015)
Authors : Sarah M. Martyn, Dr. Dermot F. Brougham
Affiliations : School of Chemical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland
Resume : Colloidally stable superparamagnetic iron oxide nanoparticles (NPs) and their assemblies are well known to be excellent contrast agents in MRI applications 1. Next generation agents are anticipated to be multi-functional in nature, hence platform technologies for the preparation of monodisperse NPCs of one or more components with tight size control are required. This study describes the preparation of NPCs by a polymer mediated approach with a particular focus on the assembly mechanism and the effect of NPC structure on the magnetic resonance properties of the NPC suspensions. The effect of NP shape and size, polymer properties and other assembly conditions, on the formation of NPCs was also investigated. NPCs were analyzed by FE-SEM, dynamic light scattering, hyperthermia and field cycling NMR spectroscopy. On preparation of colloidally stable NPCs, the ratio of r2:r1 was found to increase dramatically indicating that NPCs have potential as next generation T2 weighted MRI Contrast agents. A shift in the frequency at which maximum relaxivity was also observed, consistent with the presence of larger NPs. This effect was found to be more profound in the case of cubic or faceted NPs of similar total volume. References: 1 Pankhurst, Q.A. , Connolly, J., Jones, S.K., Dobson, J.. (2003). Applications of magnetic nanoparticles in biomedicine. Journal of Physics D: Applied Physics. 36 (13), R167-R181.
Authors : Atiye Pezeshki, Seongil Im
Affiliations : Institute of Physics and Applied Physics,Yonsei University
Resume : The Two-dimensional (2D) layered nanomaterials for semiconductor channel have recently been attracting great attentions from researchers in many possibilities of future applications such as high speed electronics, flexible electronics, and immunity of short channel effects in scale-down transistors. Transition-metal dichalcogenides (TMDs) are well-known type of 2D nanomaterial with the common formula MX2, where M is a transition metal element from group IV-VII (M = Mo, W, Nb, Re, and so on) while X is a chalcogen element (X = S, Se, Te). In general, M atoms are sandwiched between X atoms to form a single layer, and each layer can be stacked together via van der Waals forces, which make 2D TMDs easily cleaved by scotch tape, or other similar techniques. Among TMD families with ultra-thin layers, molybdenum disulfide (MoS2), tungsten dislenide (WSe2), and molybdenum ditelluride (α-MoTe2) are semiconductors with their bandgaps of more than 1 eV; depending on their layer numbers, the band gap ranges from 1 eV to 1.8 eV while their band gap properties changes from indirect to direct type as their layer number decreases to monolayer. The band gap of MoTe2 is almost the same as that of silicon, which forecasts that MoTe2 may become a candidate to be used along with silicon although further study must be followed in this regard. In the present study, we demonstrated high performance heterogeneous but Mo-based complementary (Mo-based CMOS) inverters which take α-MoTe2 as a p-type channel for a patterned back gate FET and MoS2 as n-channel for the other FET in the inverter. Our p-channel FET with nanosheet α-MoTe2 showed much higher ON-current than previously reported ambipolar MoTe2 FETs, since we used a properly-deep work function metal, platinum (Pt), for S/D contact. As a result, our Mo-based CMOS device with nanosheet channels demonstrated high CMOS performances in switching dynamics and electrostatic behavior; high voltage gain of ~ 12 and 60 micro-second switching delay at longest were displayed at a few volts. (The switching speed measurements were limited by our equipment (up to only 1 kHz) but we regard that much higher switching speed must have been guaranteed from our CMOS inverter.)
Session XII : Pablo Guardia
Authors : Jose Hierrezuelo and Dermot Brougham
Affiliations : Dublin City University
Resume : In the last decades, there has been a huge research effort aimed at developing methods to exert control over nanoparticle (NPs) assembly to produce well defined structures with a strong internal order and biocompatibility [1, 2]. In the present study, we describe a simple electrostatically driven approach to assembling opposite surface-charged iron oxide nanoparticles into nanoparticle clusters (NPCs) in aqueous suspension. The strategy include one-step synthesis of stable and functionalized NPs using two different ligands, sodium citrate tribasic for negative surface-charged NPs (dhyd = 12.3 nm, PDI = 0.11), and (3-Aminopropyl)triethoxylsilane (APTES) for positive surface-charged ones (dhyd = 13.8 nm, PDI = 0.13),. The initial aim is to form monodisperse single-layered assemblies. Detailed characterization of the stabilized suspensions, as a function of pH, including concentration determination, dynamic light scattering (DLS), and zeta-potential, NMR and SEM will be described. It was found, as expected, that the ratio of positive to negative NPs is critical, with lower ratios resulting in lower NPC sizes and surprising cluster stability.  J.-P. Chapel, J.-F. Berret. Current Opinion in Colloid & Interface Science, 17 (2012) 97105.  Zhao-Xia Cai and Xiu-Ping Yan. Nanotechnology 17 (2006) 42124216.
Authors : Punit K. Dhawan*, 1, Meher Wan1, 2, R.R.Yadav1
Affiliations : 1Department of Physics, University of Allahabad, Allahabad-211002, India; 2Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur-721302 India
Resume : In this paper, we have reported the synthesis of cobalt ferrite nanoparticles with the wet chemical route. SEM photographs confirm the nanostructure formation and XRD pattern characterization confirms the crystalline nature. The X-ray diffraction analysis of synthesized product confirmed the formation of cobalt ferrite nanoparticles having minimum crystallite size 18.84 nm. FTIR spectroscopy is employed to get the information about the vibrational bands. The magnetic properties of the cobalt ferrite are measured with the VSM technique. The magnetic properties of the synthesized ferrites are explained with the help of models based on different mechanisms. The nano-structured super-paramagnetic cobalt ferrite particles act as single domains which are small enough to overcome energy barriers that would prevent alignment in the direction of the magnetic field at room temperature. High susceptibility is observed in the synthesized nanoparticles, thus these ferrites do not need very high magnetic fields or very low temperatures to reach saturation.
Authors : Jenny Merlin, Jacek Stolarczyk
Affiliations : Photonics and Optoelectronics Group, Ludwig-Maximilians-Universität München, Amalienstr. 54, 80799 Munich (Germany)
Resume : Magnetic nanoparticles (MNPs) have recently shown great potential for various technological applications e.g. contrast agents for magnetic resonance imaging (MRI), drug delivery and information storage. MNPs can then be used as building blocks for producing magnetic nanoclusters (MNCs) with enhanced magnetization and tailored collective properties. There, we repeat the formation of MNCs by self-assembly and encapsulation of polystyrene (PS) passivated iron oxide MNPs. The controlled aggregation of the MNPs is driven by the fine interplay between hydrophobic steric, magnetic and van der Waals forces, upon modification of solvent composition. We then employed an amphiphilic diblock copolymer (polystyrene-b-polyacrylic acid) to encapsulate the MNCs into a hydrophilic shell, ensuring their stability in aqueous environments [1,2]. The resulting structures were characterized in terms of magnetic, optical and structural properties. 1. A. Sánchez-Iglesias et al., ACS Nano, 2012, 6, 11059. 2. A. S. Urban et al., Nano Letters, 2013, 13, 4399.
|18:00||Best Student Presentation Awards Ceremony and Reception (Main Hall)|
No abstract for this day
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