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Established and emerging nanocolloids: from synthesis & characterization to applications

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The Symposium F offers the opportunity to all contributions to be considered as submissions to pss for peer-reviewed publication in pss – physica status solidi

The Symposium F organisers are delighted to announce that the E-MRS Young Scientist Awards have been received by
- Ramzy Abdelaziz "Green Nanolab in a Leidenfrost Drop"
- Sotirios Christodoulou "Controlling the Emission Rate and Oscillation Strength via Shape-Control in 2D Colloidal Nanocrystals"

The committee members have selected for the quality of their Oral Presentation:
- Maria Wuithschick "Turkevich in new robes: 3 key questions answered for an old gold nanoparticle synthesis"
- Kevin McPeak "Chiral Nanoparticles for Visible and Ultraviolet Plasmonics"
- Julie Ruff "Increased stability of hollow gold nanospheres stabilized with mono-, bi- and tridentate PEG thiols"
- Anthony Désert "High-yield synthesis of nanocolloids with valence"
- Jannise Buckley "Chalcogenol ligand toolbox for CdSe nanocrystals and their influence on exciton relaxation pathways"

1st Poster Presentation:
- Anh T.M. Dao "Synthesis and Properties of Pt@Ag Core@Shell Nanocolloids for Biosensing Applications"
- Suelen Barg "Graphene Complex Cellular Networks"

2nd Poster Presentation:
- Zekiye Pelin Guven "Synthesis and characterization of mixed ligand chiral nanoclusters"
- Paola Lova "Hybrid ZnO:Polystyrene Nanocomposite for All Polymer Photonic Crystals"

3rd Poster Presentation:
- Bert de Roo "Gold nanoparticles for electron emission cancer treatment"
- Sophie Richard "Superparamagnetic nanoparticles for immuno imaging of brain tumor by MRI"

The Symposium F Best Oral and Poster Presentations Prizes have been announced and awarded at the end of the Symposium on Friday 30th of May, 2014.

This symposium will present the latest research in colloidal nanostructures, from their preparation and characterization to their applications in scientific areas including optoelectronic and photonic devices as well as catalysis and biomedicine. It will cover all aspects from fundamental growth issues to novel material developments for a wide range of applications and it will blend experimental with numerical and theoretical approaches.



Colloidal nanomaterials are part of an emergent class of materials prepared in solution and providing unprecedented levels of functionality. Such nanostructures can not only be used to study new physical and chemical phenomena in low dimensional systems but they also enable a route for the development of new technologies in key areas. Examples include communications and information processing, sensing and renewable energy, electronic and photonic devices, as well as biomedicine.

This symposium will provide a platform to discuss the preparation of nanocolloids, including well-established nanomaterials such as quantum dots and metal nanoparticles, but also emerging nanostructures such as doped semiconductors, ferroelectrics and multiferroics. Challenges linked to their applications will also be presented. Such applications include, but are not limited to, the latest developments of novel colloidal nanostructures used in catalysis, lasers, photodetectors, light emitting diodes, memory and optoelectronic devices, as well as bio-applications including MRI contrast agents, imaging and delivery carriers. This symposium will bring insight into the relevant fundamental materials and interfaces issues as well as material design, device fabrication, and functionality.

The symposium will bring together researchers working in academia and industry (see Scientific Committee composition) to stimulate interaction among scientists, engineers, students working on various aspects of colloidal nanostructures and their applications. Targeting this outcome, each session will be organized to associate experimental results, computational modeling, and theoretical presentations to complement one another and to create long-lasting opportunities of scientific interaction between attendees. Overall this symposium will favor informal interactions and will help to strengthen this community to unravel new research directions, which is the key for the ultimate success of colloidal-nanostructure based applications.


Hot topics to be covered by the symposium:

  • Colloidal Synthesis, Crystallinity Control, Characterisation and "Self/triggered" Assembly of Nanomaterials
  • Emerging Nanoscale Materials and Switchable Properties: Doping, Ferro-, Piezo-, Thermo-electric; Multiferroic; Electro-, Magneto-, Photo-chromic; etc.
  • Bio-inspired Systems and Bio-Applications
  • Nanomagnetism and Spintronics
  • Colloidal Nanoplasmonics
  • Photonic Properties & Spectroscopy of Nanoparticles (optical, THz, etc.)
  • Nanoparticle-Molecule Hybrid Systems & Surfaces and Interfaces at Nanometer Scales: from Electronics to Catalysis
  • Energy Conversion and Storage
  • Optoelectronic & Hybrid Devices (LEDs, FETs, Memory, Sensors, etc.)


List of invited speakers (confirmed):

  • Amanda Barnard (CSIRO, Australia)
  • Jean-Yves Bigot (IPCMS - CNRS - Strasbourg University, France)
  • Michel Calame (Basel University, Switzerland)
  • Celso De Mello Donega (Utrecht University, Debye Institute for Nanomaterials Science, The Netherlands)
  • Florence Gazeau (Paris-Diderot University, France)
  • Justin Holmes (University College Cork, Ireland)
  • Tim Lian (Emory University, USA)
  • Stephan Link (Rice University, USA)
  • Liberato Manna (ITT, Italy)
  • Colin Raston (Flinders University, Australia)
  • Aurora Rizzo (CNR nano, Italy)


Scientific committee:

  • Jeyadevan Balachandran (The University of Shiga Prefecture, Japan)
  • Arnaud Brioude (Université Claude Bernard Lyon; France)
  • Harald Brune (Ecole Polytechnique Fédérale de Lausanne; Switzerland)
  • Mostafa el Sayed (Georgia Tech, USA)
  • Wolfgang Fritzsche (Institute of Photonic Technology Jena, Germany)
  • Jean-Francois Hochepied (Ecole Nationale Supérieure des Techniques Avancées, ParisTech, France)
  • Fan Hongjin (Nanyang Technological University, Singapore)
  • Xuchuan Jiang (University of New South Wales, Australia)
  • Antonios Kanaras (University of Southampton, UK)
  • Todd Krauss (University of Rochester, USA)
  • Luc Lenglet (Neelogy company)
  • Iwan Moreels (Istituto Italiano di Tecnologia @ Genova, Italy)
  • Paul Mulvaney (University of Melbourne, Australia)
  • Chris Murray (University of Pennsylvania, USA)
  • Thomas Nann (University of South Australia, Australia)
  • David Norris (Eidgenössische Technische Hochschule Zürich, Switzerland)
  • Nicola Pinna (Humboldt-Universität zu Berlin, Germany)
  • Amy Prieto (Colorado State University, USA)
  • Romain Quidant (Institut de Ciències Fotòniques @ Barcelona, Spain)
  • Lyse Santero (Magnisense company)
  • Daniel Scherman (Université Paris V - CNRS UMR 8151 - Inserm U1022, France)
  • Seiichi Takami (Tohoku University, Japan)
  • Dmitry Talapin (University of Chicago, USA)
  • Rafael Torres (King's College London, UK)
  • Claire Wilhelm (Université Paris V, France)
  • David Zitoun (Bar-Irlan University, Israel) 


Symposium organizers:


Pascal André
University of St Andrews
School of Physics and Astronomy
KY16 9SS St Andrews
Phone: + 44 1334463036


Mathieu Maillard
LMI / Département de Chimie
Université Claude Bernard - Lyon 1
43 Boulevard du 11 novembre 1918
69622 Villeurbanne Cedex
Phone: + 33 (0) 4 72 43 35 64


Gordana Dukovic
Department of Chemistry and Biochemistry
University of Colorado Boulder
UCB 215 Boulder, CO 80309
Phone: + 1 303 735 5297


Laurence Motte
Laboratoire CSPBAT (UMR CNRS 7244)
Equipe LPBS - Groupe Nanomatériaux
Université Paris 13
74 rue Marcel Cachin
93017 Bobigny cedex
Phone: + 33 (0) 1 48 38 77 07


Richard Tilley
School of Chemical and Physical Sciences
MacDiarmid Institute
Victoria University of Wellington
6035 Wellington
New Zealand
Phonel: +64 (0) 4 4635016

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Authors : L.-M. Lacroix, P. Moutet, A. Loubat, M. Imperor-Clerc, L. Ressier, G. Viau
Affiliations : LPCNO, Universite de Toulouse, INSA-UPS-CNRS UMR 5215, F-31077 Toulouse, France LPS, Universite Paris-Sud CNRS UMR 8502, Bat. 510, F-91405 Orsay, France

Resume : Recently, ultrathin gold nanowires (NWs) prepared by reduction of HAuCl4 in solution of oleylamine (OY) attracted lots of interest due to their size homogeneity (diameter 1.7 nm, micrometer length) [1] with application as foldable optoelectronics membranes [2,3] or elastic coiled springs [4]. Their unique 1D feature confers them remarkable conductivity properties such as quantum phenomena at room temperature [5,6] but the study of the electronic properties of single NW still remains a technological challenge and requires a good understanding of their physical properties. SAXS, NMR and XPS studies allowed us to describe the self assembly of ultrathin Au NWs into a hexagonal super-lattice with a parameter of 9.7 nm well explained by a OY Cl-/OY bilayer at the surface of each NW and suggests a 1D micellar growth mechanism [7]. We have also showed that these Au NWs dispersed in hexane exhibit a negative electric charge that makes them well-suited for a Coulomb force directed assembly by AFM nanoxerography. Isolated NWs were trapped on positive patterns at the surface of PMMA thin layers using this technique opening the way to the connection of individual NWs by soft lithography. 1 H. Feng et. al, Chem. Comm., 2009, 1984 2 Y. Chen et al., Adv. Mater. 2013, 25, 80 3 A. Sanchez-Iglesias et al., Nano Lett. 2012, 12, 6066 4 J. Xu et al., J. Am. Chem. Soc. 2010, 132, 11920 5 S. Pud et al., Small, 2013, 9, 846 6 A. Loubat et al., Nano Res. 2013, 6, 644 7 A. Loubat, submitted

Optical & Magnetic Probing of nanoParticles : Pascal André, Richard Tilley, Jean-Yves Bigot
Authors : J.-Y. Bigot*, H. Kesserwan, V. Halté, M. Vomir
Affiliations : Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg and CNRS 23 rue du Loess, 67034 Strasbourg, France

Resume : When studying nano-materials with ultrashort optical pulses, with femtosecond duration, the objects are suddenly brought out of equilibrium and one can observe the relaxation of energy and momentum in a broad time scale ranging from tens of femtoseconds to a few nanoseconds. For magnetic systems, the momentum is the important dynamical quantity to determine as it carries the information on the magnetic state. In particular it allows understanding how the magnetic moment of the nanoparticles (the macro-spin) varies due to the new equilibrium state set after the pulse excitation. In that context the dynamics strongly depends on the anisotropy of the magnetic nano-systems which are considered. In this contribution we will illustrate the effects related to this dynamical change of anisotropy. We first examine the case of CoPt and core-shell Co-Pt nanoparticles. For CoPt nanoparticles, the large anisotropy defines the equilibrium state of the magnetization. The macro-spin can therefore start precessing after the optical perturbation sets a new equilibrium state. This precession can be observed during hundreds of picoseconds and it is an ideal situation to characterize the FMR (ferromagnetic resonance) parameters of the magnetic nano-objects. In the case of the core-shells, the absence of anisotropy axis prevents from observing a clear dynamical torque and the magnetization dynamics simply results from a heating of the spins which transfer their momentum to the lattice on the picosecond time scale. Second, we address the important question of the inter-particles interactions. We will show how it can affect either the energy relaxation (charge dynamics) or the magnetic momentum (spins dynamics) in assemblies of cobalt super-paramagnetic nanoparticles. For well-organized assemblies, like for example in self-assembled supracrystals of Co nanoparticles, a spectacular collective vibration of the nanoparticles takes place. In contrast, the magnetic order due to inter-particles dipolar interaction is not strong enough to induce major dynamical change of the macro-spin, else than the single particle case. The spatial limits defining the conditions of collective effects will be examined in a theoretical model. Finally we will give some perspectives that may lead to further interesting material developments regarding the design of anisotropic nano-systems like for example in cobalt ferrites. JYB acknowledges financial support from the European Research Council via the ERC Advanced Grant ATOMAG (ERC-2009-AdG-20090325 247452) and the Agence Nationale de la Recherche in France, Labex NIE.

Authors : G. Allan a, C. Delerue a A. Al-Otaify b, D.J. Binks b, S.V. Kershaw c, S. Gupta c, A.L. Rogach c
Affiliations : aIEMN-Department ISEN, UMR CNRS 8520, Lille 59046, France. bSchool of Physics and Astronomy & Photon Science Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK. cDepartment of Physics and Materials Science & Centre for Functional Photonics (CFP), City University of Hong Kong, Hong Kong S.A.R.

Resume : HgTe nanocrystals presently receive growing interest because the negative band gap in bulk HgTe enables tunability of the gap from the infrared to the near infrared in quantum dots thanks to the quantum confinement. Therefore we propose a tight-binding model of HgTe which gives an accurate band structure in a wide energy range of energy compared to recent ab initio calculations. The inverted band structure near the Fermi level and its temperature dependence are also very well described. Using this model, we study the effects of the quantum confinement on the electronic structure of HgTe quantum dots. We calculate the optical absorption spectra of quantum dots with various shapes and diameters up to 10 nm, including excitonic effects using a configuration interaction approach [1]. The optical spectra are consistent with recent experimental data. We also simulate the multiple exciton generation and we discuss the results of ultrafast transient absorption spectroscopy experiments performed on HgTe nanocrystals. [1] G. Allan and C. Delerue, Phys. Rev. B 86, 165437 (2012). [2] A. Al-Otaify, S.V. Kershaw, S. Gupta, A.L. Rogach, G. Allan, C. Delerue and D.J. Binks, Phys. Chem. Chem. Phys. 15, 16864 (2013).

Authors : Laurence Ourry 1, Sofia Marchesini 1, Ngo Thi Lan 2, Silvana Mercone 2, Damien Faurie 2, Fathi Zighem 2, Sophie Nowak 1, Michel Delamar 1, Souad Ammar 1, Fayna Mammeri 1
Affiliations : 1 ITODYS, Université Paris Diderot, Sorbonne Paris Cité, 75013 Paris, France 2 LSPM, Université Paris Nord, Sorbonne Paris Cité, 93430 Villetaneuse, France

Resume : The multifunctionality of multiferroic materials strongly depends on the efficiency of couplings between different ferroic orders. Improving the magnetoelectric (ME) coupling at room temperature between ferroelectric (FE) and ferromagnetic (FM) orders can allow the manipulation of the magnetization by an electric field and vice versa, opening the way for writing and reading at low energy cost in magnetic memories. Moreover, the opportunity to control this ME coupling through a low mechanical and reversible stress using flexible hybrid films makes it more appealing for new smart applications. In this context, we first prepared CoFe2O4 nanoparticles (NPs) using the polyol process. Half of the NPs were functionalized in order to promote interactions between NPs and PVDF. Then, flexible CoFe2O4-PVDF based hybrid films were prepared by dispersing NPs in a solution of PVDF and melt processing. The polymer polar phase content and the hybrid interface between both components are key parameters for improving coupling between FM and FE phases in nanocomposite. As PVDF exhibits two main polymorphs, α (apolar phase) and β (FE phase), we first studied the influence of temperature to obtain the highest content of β phase. Finally, in situ tensile tests were combined either to X-ray diffraction in order to monitor the α to β phase transition or to near-field microscopy (in magnetic and piezoelectric force configuration) for local ME effect imaging.

Authors : A. Ayouch(1), X. Dieudonné(2), G. Vaudel(1), H. Piombini(2), K. Valle(2), P. Belleville(2), V. Gusev(1) , P. Ruello(1)
Affiliations : (1) Institut des Molécules et Matériaux du Mans, UMR-CNRS 6283, Université du Maine, Avenue O. Messiaen, 72085 Le Mans, France (2) CEA, DAM, Le Ripault, BP 16, 37260 Monts, France

Resume : New functional materials are currently can be created by assembling the nanoparticles. In order to obtain the desired macroscopic properties of a new material a perfect control of the contacts between nanoparticles is necessary. Therefore, the physics and chemistry of nanocontacts are among the central issues for the design of the nanocomposites. We demonstrate that the ultrafast opto-acoustic technique, based on the generation and detection of resonance vibrations of the colloidal films by femtosecond laser pulses [1-3], i.e., resonance hypersonic spectroscopy, is very sensitive to the elastic properties of the contacts between the nanoparticles composing the films as well as to the properties of the contacts between the nanoparticles and the substrate. In particular, we observe and evaluate how strongly the interaction of the nanoparticles via either van der Waals-bonded or covalent-bonded coatings modifies such macroscopic parameter as the sound velocity in the colloidal solid. Starting from the measured resonance vibration frequencies it is possible to estimate quantitatively, first, the macroscopic elastic modulus of the colloid, second the rigidities of the nanocontacts between the nanoparticles and, finally, the surface energies of the nanoparticles coated by molecular layers. Our experimental measurements and theoretical analysis demonstrate that, by using for coating of the nanoparticles the molecular layers with high surface energy/tension, it is possible to increase the rigidities of the inter-particle contacts of the colloidal films [4]. References: [1] Thomsen, C.; Grahn, H. T.; Maris, H. J.; Tauc, J. Surface Generation and Detection of Phonons by Picosecond Light Pulses. Phys. Rev. B 1986, 34, 4129–4132. [2] M. Lomonosov, A. Ayouch, P. Ruello, G. Vaudel, M. R. Baklanov, P. Verdonck, L. Zhao, V. E. Gusev Nano-Scale Non-Contact Depth-Profiling of Mechanical and Optical Properties of Nanoporous Low-k Materials Thin Films , ACS Nano, 2012, 6 (2), pp 1410–1415. [3] C. Mechri, P. Ruello, V. Gusev, Confined coherent acoustic modes in tubular nanoporous alumina film probed by picosecond acoustics methods, New. J. Phys. 14 (2012) 023048. [4] A. Ayouch , X. Dieudonne , G. Vaudel , H. Piombini , K. Valle , V. Gusev , P. Belleville , and P. Ruello, Elasticity of an Assembly of Disordered Nanoparticles Interacting via either van der Waals – Bonded or Covalent-Bonded Coating Layers. ACS Nano, 6, 10614-10621 (2012)

Authors : Inderjeet Singh, Amreesh Chandra
Affiliations : Department of Physics, Indian Institute of Technology, Kharagpur, 721302 West Bengal, India

Resume : Size confinement is a promising technology to tailor the physical properties of multifunctional systems. Recently, Cr-based systems have shown simultaneous presence of ferromagnetic, ferroelectric, photoluminescence and catalytic properties which makes them important functional materials. We report a significant enhancement in the magnetic response of YCrO3 nanoceramics below 10K. Significant control over the particle size could be obtained by synthesizing the particle under droplet confinement in inverse miniemulsion. YCrO3 nanoparticles shows antiferromagnetic characteristics below 140K with significant increment in the magnetic moment when the sample is cooled below 10K. The hysteresis loop nature shows a cross over to a weak ferromagnetic characteristics. This magnetic behaviour can be explained using the concept of elongated grains or mesocrystals. Interesting modulation in the ferroelectric properties are also discussed by analyzing the frequency dependent dielectric and XRD data.

Authors : Moniruzzaman Syed1)*, Caleb Glaser2), Michael Schell2), Indrajith Senevirathne2)
Affiliations : 1Division of Natural and Mathematical Sciences, Lemoyne-Owen College, Memphis, TN38126, USA 2Department of Geology and Physics, Lock Haven University of Pennsylvania, Lock Haven, PA 17745, USA

Resume : In this study, Gold (Au) thin films were deposited on glass (SiO2) and silicon (100) substrates at room temperature (RT) in an argon (Ar) gas environment as a function of sputtering time (Tsp). The structural properties of Au films have been studied using an Atomic Force Microscope (AFM). The results of this study indicate that the structural properties of the deposited Au film are related to the conductance of the substrate. AFM micrographs of Au films show that the films on nonconductive substrates show higher coalescence for longer sputtering times. Au films deposited on conductive silicon substrates show structures that show microvoids and to homogenous structures as the sputtering time increases. On the other hand, gold films deposited to nonconductive glass substrates showed homogenous structures that changed to cluster and island-type as a function of sputtering time.

Authors : Marcin Malek1, Pawel Wisniewski2, Hubert Matysiak2, Krzysztof Jan Kurzydlowski1
Affiliations : 1Faculty of Materials Science and Engineering, Warsaw University of Technology, POLAND 2Functional Materials Research Centre, Warsaw University of Technology. POLAND * Corresponding author:

Resume : This work characterize technological properties of ceramic slurries based on yttria fillers and binder with nanocolloidal particles of Al2O3, which are used in manufacturing ceramic shell molds for investment casting of superalloys. Two different granulation (200# and 325#) of yttrium III oxide was used in weight ratio 50÷50%. Polyvinyl alcohol in an amount of 6%, 10% and 15% as 10 wt.% solution was added as a liquefier. Solid phase content in ceramic slurries was 77 wt.%. Standard industrial parameters like: Zhan 4# cup, plate weight test, pH, density, viscosity and dynamic viscosity were investigated. In addition dipping test on wax model was done. For characterization yttria powders and binder with nano Al2O3 particles, grain size, scanning electron microscopy, chemical composition and Zeta potential were studied. Obtained results proved that yttria based slurries are stable vs. time and its properties are promising in further application in industrial scale. Key words: investment casting, ceramic slurries, yttria powders, nanocolloidal Al2O3, ceramic shell moulds, rheological properties. Financial support of Structural Funds in the Operational Programme - Innovative Economy (IE OP) financed from the European Regional Development Fund - Project "Modern material technologies in aerospace industry", No. POIG.01.01.02-00-015/08-00 is gratefully acknowledged.

Authors : Jonathan De Roo, Katrien De Keukeleere, Jonas Feys, Petra Lommens, Zeger Hens and Isabel Van Driessche
Affiliations : Ghent University, Department of Inorganic and Physical Chemistry

Resume : Refractory metal oxides (HfO2, ZrO2, Ta2O5, Nb2O5) are particularly challenging to synthesize as monocrystalline, monodisperse nanoparticles (d < 10 nm) in a reproducible and economically feasible fashion. Niederberger et al. introduced the benzyl alcohol (BA) synthesis which is more environmentally friendly than surfactant-based syntheses. However, the synthesis takes several days and the resulting particles are aggregated. Here, we present a system which combines the advantages of both approaches. We focused on hafnium oxide as a model system and subsequently extended our synthesis method to other oxides. We use a cheap chloride precursor and the reaction mixture is heated via microwave heating in a closed vessel. The reaction attained full yield in three hours, which is comparable to hot injection syntheses. In the microwave synthesis, the ensemble of particles has a better size dispersion and a smaller average size (4 nm), as compared to the autoclave synthesis. The reaction mechanism was investigated and we found proof for an ether elimination process. Post-synthetic modification with a minimal amount of dodecanoic acid and oleylamine permitted the transfer of the synthesized particles from polar to nonpolar solvents. Concomitantly, aggregates are broken into the constituting nanoparticles, thus tackling the major disadvantage of the BA synthesis. Moreover, the thousand fold reduction in surfactant usage is an advantage over classical surfactant syntheses.

Authors : M. Zimbone b) G. Cacciato a), b), Ruy Sanz b), L. Romano a) ,R. Reitano a),V. Privitera b),c), M. G. Grimaldi a), b)
Affiliations : a) Dipartimento di Fisica ed Astronomia-Università di Catania, via S. Sofia 64, 95123 Catania, Italy b)MATIS IMM-CNR, via S. Sofia 64, 95123 Catania, Italy c)CNR-IMM, Stradale Primosole 50, I-95121 Catania, Italy

Resume : The development of industrial nanotechnologies is driven by the ability of manufacturing nanostructures with tunable size and properties, based on scalable and economically advantageous methodologies. Pulsed laser ablation in liquid (PLAL) is one of the most promising emerging technologies that fit these requirements. PLAL is applied for the synthesis of metal and oxide nano-colloids directly in liquid environment with unique properties as high purity, high surface activity, and the possibility of choosing different solvents depending on specific application. In order to tune the colloid properties, it is essential to understand how ablation parameters influence the formation, size and structure of nano-colloids. In the present work, we report on the synthesis of titanium oxides nano-colloid by PLAL in pure water by using a Nd:Yag laser at 1064 nm. We focus our attention on the titanium oxides nano-colloid properties, both in liquid and in dry environment. UV-Vis spectroscopy and dynamic light scattering are used for characterization in liquid. Scanning Electron Microscopy, Rutherford Back Scattering and X-Ray Diffraction were employed after drying. Spherical and stoichiometric TiO2 nanoparticles of 34 nm in mean diameter, showing both amorphous and crystalline phases, have been found. The application of these nano-particles to photo-degradation of methyl-blue dye is also presented and discussed taking as reference the properties of commercial titanium nanoparticles.

Authors : J. Timoshenko 1, A. Anspoks 1, A. Kalinko 12, A. Kuzmin 1
Affiliations : 1 Institute of Solid State Physics, University of Latvia, Kengaraga street 8, LV-1063 Riga, Latvia; 2 Synchrotron SOLEIL, l'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France

Resume : Nanostructured tungstates CoWO4 and CuWO4 are very promising catalytic materials, particularly for photocatalytic oxidation of water. The high catalytic activity of tungstate nanoparticles is partially a result of their extremely small sizes, and, consequently, high surface-to-volume ratio. Thus the properties of such material strongly depend on the atomic structure, which, in turn, can significantly differ from that in the bulk. X-ray absorption spectroscopy is a powerful technique to study the local atomic and electronic structure of nanomaterials. In this study we employ the reverse Monte Carlo method based on a novel Evolutionary Algorithm (EA) for the analysis of the extended x-ray absorption fine structure (EXAFS) spectra from nanosized (smaller than 2 nm) CoWO4 and CuWO4 powders. The EA-EXAFS approach and simultaneous analysis of the W L3- and Cu/Co K-edge EXAFS data allowed us for the first time to obtain a 3D structure model of tungstate nanoparticles and to explore in details the effect of size, temperature and transition metal type.

Authors : Anh T.N. Dao, Derrick M. Mott, Shinya Maenosono
Affiliations : School of Materials Science, Japan Advanced Institute of Science and Technology

Resume : Ag nanoparticles (NPs) show a wide range of colors corresponding to their localized surface plasmon resonance together with exceptionally high extinction coefficient associated with very high enhancement ability in Raman spectroscopy. These characteristics have made it an ideal candidate for use as a probe in sensing and bio-diagnostics applications. However, aqueous synthesis of Ag NPs still has several obstacles such as uncontrollable size and morphology of resulting NPs as well as extremely sensitive to oxidation. In our research, Pt is chosen as core material to create heterostructured Ag-based NPs in order to control size and shape of obtained core@shell NPs by seed-mediated growth mechanism. Ag in the shell is stabilized through electronic transfer effect yet still retains excellent surface plasmon resonance without compromising intensity. Our synthetic approach avoids the galvanic replacement reaction while overcoming lattice mismatch to successfully form Pt@Ag core@shell NPs which have tunable size and shell thickness. The Pt@Ag core@shell NPs are synthesized in aqueous environment and are characterized by using UV-Vis, XRD, HR-TEM, HADDF-STEM, EDS, XPS, and Raman spectroscopy.

Authors : Inderjeet Singh1,2, Samet H. Varol2, Katharina Landfester2, Rafael Muñoz-Espí2, Amreesh Chandra1
Affiliations : 1 Department of Physics, Indian Institute of Technology Kharagpur, Kharagpur 721302 West Bengal, India 2 Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany

Resume : It is shown that nanostructures of CeO2 with capsular morphology can be obtained at ambient conditions by initiating the crystallization at the liquid–liquid droplet interface in inverse miniemulsions. The extent of interfacial crystallization can be modulated by varying the concentration of cerium precursor. This also allows the fabrication of CeO2 nanocapsules with higher homogeneity and reproducibility. The size confinement forces the system to behave as an elongated grain and ferromagnetic type characteristic can be obtained at RT from CeO2 nanocapsules. The ferromagnetic parameters are comparable or better than previous reports on CeO2 nano-ceramics obtained using various thermal and pressure dependent synthesis routes. Doping of Cu in CeO2 nanostructures induces appreciable enhancement in the ferromagnetic response. The frequency dependent dielectric response of CeO2 nanoparticles also shows interesting features.

Authors : Paola LOVA 1,2,6,Luca BOARINO 3, Michele LAUS 4, Giulia URBINATI 5, Franco MARABELLI 5, Cesare SOCI 6, Davide COMORETTO 2
Affiliations : 1 Interdisciplinary Graduate School, Energy Research Institute at NTU (ERI@N), Nanyang Technological University, Singapore; 2 Department of Chemistry and Industrial Chemistry, University of Genoa, Italy; 3 National Institute of Metrological Research (INRIM), Italy; 4 Department of Life Sciences, University of Eastern Piedmont, Italy; 5 Department of Physics, University of Pavia, Italy; 6 Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore.

Resume : Polymer Distributed Bragg Reflectors (DBRs) are photonic crystals suitable for organic optoelectronic devices such as LEDs, lasers and sensors. They are usually prepared by spin coating of alternated orthogonal polymer solutions. Unfortunately, the orthogonality constraint, the relatively poor difference of polymers refractive index and the requirement of high transparency limit the available materials.1 Polymers refractive index can be engineered preserving processability and transparency using oxides nanofillers. Here we report on high optical quality DBRs prepared alternating cellulose acetate (n=1.46) and ZnO:polystyrene (PS) nanocomposite layers engineered to increase PS refractive index (n=1.58). The new DBRs show a photonic band gap in the near infrared spectral region, an extended diffraction pattern up to the fifth order and the expected dependence on light polarization and incidence angle. Nanocomposite thin films are prepared loading into a PS solution ZnO nanoparticles grown by low temperature solvothermal synthesis after a graft reaction with a silane performed to reduce phase segregation in the non-polar matrix. Spectroscopic ellipsometry shows a 3% increase of PS refractive index upon ZnO loading of 5% v/v in agreement with effective medium theory. These results suggest a new strategy for the development of highly processable hybrid DBRs for photonic applications. 1 L. Frezza, M. Patrini, M. Liscidini and D. Comoretto, J. Phys. Chem. B 115 (40), 19939 (2011)

Authors : Romain Aufaure, Yoann Lalatonne, Laurence Motte and Erwann Guénin
Affiliations : Laboratoire CSPBAT (UMR7244) ; LPBS ; Université Paris 13 ; France

Resume : Water soluble gold nanoparticles (GNPs) own physical and chemical properties with a large scope of application in the biomedical research. Our project aims to develop new synthetic pathways for the direct synthesis of GNPs already possessing functionality allowing easy access to bio functionalization. This is achieved by using synthesized water soluble molecules. These molecules are bifunctional : One functional group is able to both reduce gold(III) chloride and to coat the surface of the obtained GNPs. The other functional group will remain inert during the NPs synthesis and will allow further chemoselective GNPs functionalization. Herein we will present the mechanism of this GNPs synthesis. We have demonstrated the related mechanism of this colloid formation and the interaction between our bifunctional molecules and the gold surface by classical analytical chemistry techniques. Optimization of the various synthesis parameters (temperature, concentration and pH) have been assessed to yield homogeneous GNPs of size ranging from 13-21 nm. Then reactions at the surface with the remaining, functional group have been characterized, confirming their chemoselective reactivity. These new GNPs are also used as a building block for sized controlled covalent assemblies preparation. The controlled size assemblies are water soluble and presents specific optical properties shifting from blue to NIR absorption yielding to promising in vivo applications such as hyperthermia.

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Authors : David Beke, Zsolt Szekrenyes, Istvan Balog, Katalin Kamaras, Balazs Rozsa, Istvan Palfi, Pál A. Maák, Adam Gali
Affiliations : Wigner Research Centre for Physics; Institute of Experimental Medicine; Budapest University of Technology and Economics;

Resume : Visual analysis of biomolecules is an integral avenue of basic and applied biological research. Quantum dots (QDs) are semiconductor inorganic nanoparticles that are emerging as alternative or complementary tools to the organic fluorescent dyes currently used in bioimaging. Although these QDs have great potential as probes for bioimaging, certain limitations may restrict their applications. Cytotoxicity strongly influencing is one of the major limiting factors for the application of II-VI QDs in efficient in vivo imaging. We propose silicon carbide (SiC) QDs for bioimaging in order to eliminate numerous disadvantages of traditional QDs. SiC is a stable, chemically inert wide band gap indirect semiconductor. Biocompatibility of bulk SiC and SiC QDs has been proven by several research teams. We developed a two-step experimental routine of producing SiC QDs. First, microcrystalline SiC (SiC MCs) is formed by reactive bonding method which, principally, allows us to produce highly doped SiC MCs in order to modulate the optical properties of the prepared SiC QDs made from them. SiC QDs form by electroless wet chemical etching of the SiC MCs [1]. These SiC QDs are less than 3 nm in diameter and make stable colloid sol in water thanks to the surface termination that was studied by infrared spectroscopy. We developed a simple separation method to overcome of the relatively large size distributon of collodial SiC QDs that could be suitable for two-photon study of neuron cells.

Authors : Rute Fernandes(1), Neil R. Smyth (2), Simone Nitti (3), Michael R. Arden-Jones(2), Antonios G. Kanaras (1)
Affiliations : (1) Physics and Institute of Life Sciences, Faculty of Physical and Applied Sciences, University of Southampton, Southampton, United Kingdom, SO171BJ (2) Faculty of Medicine, University of Southampton, Southampton, United Kingdom, SO171BJ (3) Istituto Italiano di Technologia, Via Morego 30, 16163 Genova, Italy.

Resume : Understanding the interactions of nanoparticles with skin is of high importance for the development of new ways to deliver drugs efficiently but also in order to realize potential toxicity risks. The study of nanoparticle penetration through skin is a complex research task because it iis associated with a number of experimental parameters that can not be easily controlled related to the complexity of the skin structure and the physicochemical characteristics of nanoparticles. In this presentation we follow a thorough analytical approach to answer key questions concerning these interactions. We will particularly focus on how the charge, shape and function of nanoparticles influence the penetration through skin. For our studies we chose to work with gold nanoparticles due to the ease of their surface modification. To gain a good understanding, we employ a number of techniques such as ICP-OES to quantitatively measure the penetration of nanoparticles, as well as two-photon spectroscopy and tem cross sectioning to analytically detect the particles in the skin. Moreover we will hypothesize potential mechanisms of penetration.

Authors : Naoki Komatsu, Li Zhao, Toku Yasuda, Hongmei Qin, Takahide Kimura
Affiliations : Shiga University of Medical Science

Resume : Biomedical applications of nanodiamond (ND) have been investigated extensively due to its low toxicity, non-bleaching fluorescence, and high extensibility of the surface functionality through covalent organic functionalization. For in vivo applications such as drug carrier and imaging probe, ND should form a stable hydrosol under a physiological environment. In this context, we recently found that polyglycerol (PG) functionalization is very effective to impart the sufficient solubility and stability to ND [1]. In addition, the stable hydrogel of PG-functionalized ND (ND-PG) enabled precise characterization of the chemical structure by solution phase NMRs. Quantitative analyses were also conducted by elemental and thermogravimetric analyses. The ND-PG was subjected to further organic transformations at a number of hydroxyl groups on the PG layer to add more functions. As a result, we successfully prepared the ND-based drug carrier with acid-responsive platinum drug [2] and MR imaging probe with gadolinium [3] and applied them to in vivo and in vitro evaluations. [1] L. Zhao, N. Komatsu, Angew. Chem. Int. Ed., 50 (6), 1388-1392 (2011) [2] L. Zhao, N. Komatsu, X. Chen, submitted [3] L. Zhao, N. Komatsu, J. Nanosci. Nanotechnol. in press

Authors : Daniel J. Gargas, Emory M. Chan, Alexis D. Ostrowski, P. James Schuck, and Bruce E. Cohen
Affiliations : The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA

Resume : Imaging cells at the single-molecule level reveals heterogeneities that are lost in ensemble imaging experiments. An ongoing challenge is the development of single-molecule probes with the requisite photostability, brightness, and continuous emission. Upconverting nanoparticles (UCNPs) overcome problems of photostability and continuous emission, and their upconverted emission can be excited with biologically benign NIR light at much lower powers than those required for conventional multiphoton imaging probes. The brightness of UCNPs, however, has been limited by open questions about energy transfer and relaxation within individual nanocrystals and unavoidable trade-offs between brightness and size. We have developed UCNPs with d < 10 nm that are over an order of magnitude brighter under single-particle imaging conditions than the brightest bulk compositions, allowing us to visualize single upconverting nanoparticles as small as fluorescent proteins. We use a combination of advanced single-particle characterization and theoretical modeling to find that surface effects become critical at d < 20 nm, and that the higher fluences used in single-molecule imaging fundamentally change the factors that determine nanocrystal brightness. We find that factors known to increase brightness in bulk experiments are unimportant at higher excitation powers, and that, paradoxically, the brightest probes under single-molecule excitation are barely luminescent at the ensemble level.

Authors : Mohammad Mehdi Shahjamali, Can Xue*
Affiliations : School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore

Resume : Noble metal nanostructures have attracted extensive research attentions due to their intriguing optical properties. In particular, silver nanoprisms are of great interest due to their size-dependent surface plasmon resonance bands that are tailorable in the visible and near-IR range. However, the poor stability of silver nanoprisms against oxidation and etching restricts their applications. Herein we demonstrate a simple process of gold-coating on silver nanoprisms. The resulting Ag@Au core–shell structure preserves the optical signatures of nanoprisms and offers versatile functionality and better stability against oxidation. Further, by slightly modifying the gold-coating process, we can obtain various functional Ag/Au bimetallic structures, such as Ag@Au-framed prisms and ultrathin nanoframes. [1,2]These interesting Ag/Au nanostructures are capable of showing high sensitivity in refractive sensing and strong enhancement of polaron yield in organic photovoltaics. Reference: [1] M. M. Shahjamali, M. Bosman, S. W. Cao, X. Huang, X. H. Cao, H. Zhang, S. S. Pramana, C. Xue*, Small 2013, 9, 2880-2886. [2] M. M. Shahjamali, M. Bosman, S. W. Cao, X. Huang, S. Saadat, E. Martinsson, D. Aili, Y. Y. Tay, B. Liedberg, S. C. J. Loo, H. Zhang, F. Boey, C. Xue*, Adv. Funct. Mater. 2012, 22, 849-854.

Authors : Christophe Lavenn,1 Florian Albrieux,2 Alain Tuel1 and Aude Demessence*1
Affiliations : 1. Institut de Recherches sur la Catalyse et l’Environnement de Lyon, UMR 5256, CNRS / Université Lyon 1 - Villeurbanne, France. 2. Centre Commun de Spectrométrie de Masse, UMR 5246, CNRS / Université Lyon 1 - Villeurbanne, France.

Resume : Gold nanoparticles, less than 5 nm, exhibit a catalytic activity in many chemical processes. However polydisperse particles obscure the interesting size-dependent catalytic activity of nanogold. Recently, atomically well defined thiolate-capped Au nanoclusters (denoted as Aun(SR)m) have been successfully isolated and their catalytic properties have been demonstrated. These monodispersed functionalized clusters, with gold core between less than 1 nm and more than 2 nm, hold promises as a new generation of catalysts. More importantly, these nanoclusters permit in-depth studies on the subtle correlation of structure and catalytic activity, since they are well defined and their crystallographic structures start to be solved. To investigate the influence of the size, the type of ligands at the surface and also the support effect, different nanoclusters have been synthesized. New clusters made of 4-aminothiophenol (HSPhNH2) have been synthesized, such as Au25(SPhNH2)17, and fully characterized by mass spectrometry, X-ray diffraction and XPS. Moreover these clusters exhibit absorption bands related to their molecular state. Catalytic activity for oxidation of alkene and alcohol derivatives of these colloidal or supported clusters were investigated and compared to the commonly used Aun(SCH2CH2Ph)m nanoclusters. At the opposite of the bare gold nanoparticles, the presence of the ligands around the clusters leads to a much better selectivity of the product.

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Authors : Dymtro Dedovets1,2, Satyabrata Si1, Emilie Pouget2, Sabrina Habtoun3, Said Houmadi3, Chistian Bergaud3, Reiko Oda2, Marie-Hélène Delville1*,
Affiliations : 1 ICMCB/CNRS, Universite de Bordeaux, Pessac, France; 2 Chimie et Biologie des Membranes et des Nano-objets, allée de St Hilaire, 33600 Pessac, France 3 CNRS, LAAS, 7 avenue du Colonel Roche, F-31400 Toulouse, France *e-mail:

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 mechanical properties of SiO2 and SiO2@MxOy nanotubes and helical nanosprings synthesized by an original and simple technique from organic nanotubes through inorganic transcription. These nano-objects have potential applications in nano-electromechanical systems (NEMS), ranging from physical sensing and signal processing to ultra-low power radio frequency signal generation, thanks to their striking features. NEMS have been generally based on 1D nano-objects, such as carbon nanotubes [1] or silicon nanowires [2]. However, the use of 3D nanostructures such as nanohelices would allow a significant improvement the electromechanical performances of functional nanodevices, due to their specific properties. The originality of our synthesis method consists in the possibility to obtain 3D nanostructures with specific morphology and properties. In the present work, functional hybrid nano-helices are synthesized by use of amphiphilic organic chiral self-assemblies forming very well defined helix or ribbons structures and exploits them as templates for inorganic nanomaterial formation [3]. A bio-inspired mineralization of these self-assemblies allows creating silica nano-helices with very well controlled morphologies. We focus particularly on the formation of short helices (length control), individualized and well-dispersed in solution. Using this method, NTs and helical nanosprings with controlled dimensions were fabricated using inorganic materials usable in functional nanodevices such as sensors, actuators and resonators. To the best of our knowledge, nothing has been published concerning the mechanical properties of inorganic nanotubes or nanosprings templated from organic self-assemblies. Their elastic properties were determined by performing three-point bending tests on suspended NTs and nanosprings over micro-cavities using an atomic force microscope (AFM).. The SiO2 nano-objects were subjected to a load f at midpoint using an AFM tip by performing force vs. distance (F-d) curve measurements. The elastic modulus E was then determined using the beam bending theory of clamped-clamped beam [4], that gives the relationship between E and the elastic deformation of a suspended and clamped cylindrical beam or tube. For all tested NTs the average value of the elastic modulus E was determined to be 73.3 ± 6.7 GPa, which is comparable to that of bulk SiO2 [5] as well as amorphous SiO2 nanowires obtained using chemical vapor deposition [6]. On the other hand, the average value of E measured for helical nanospring was 70 ± 7 GPa, which is in very good agreement with the result obtained for the NTs. This is of paramount importance because the nanospring exhibit unconventional physical properties and can be advantageously used as building blocks in functional nanodevices. The first advantage concerns their helicity and periodicity that can be varied to tune the spring constant. In addition, due to their structural flexibility, the helical shape is also ideal for inducing polarization effects under mechanical stress [7]. The obtained results demonstrate that the proposed synthetic route for obtaining inorganic NTs is robust and reproducible. [1] K. Jensen, K. Kim, A. Zettl, Nature Nanotechnology, (2008) 3, 533 - 537. [2] Lih J. Chen J. Mater. Chem., (2007) 17, 4639-4643. [3] T. Delclos, C. Aimé, E. Pouget, A. Brizard, I. Huc, M.-H. Delville, R. Oda, Nano Lett. (2008), 8, 1929 - 1935, [4] J. M. Gere, S. P. Timoshenko, Mechanics of Materials, PWS-KENT, Boston, Massachusetts, (1990) Third Edition [5]. B. Bhushan, Handbook of Nanotechnology (Springer, Berlin, 2007) 2nd edition, p. 1040 [6] H. Ni, X. Li, H. and Gao, Appl. Phys. Lett. (2006) 88, 043108 [7]. J.P. Singh et al. Applied Physics Letters (2004) 84, 3657.

Authors : M. Pedroni, A. Speghini
Affiliations : Dipartimento di Biotecnologie and INSTM, Unita' di Verona, Universita' di Verona, Strada le Grazie 15, 37134 Verona, Italia

Resume : Alkaline-earth fluorides nanoparticles doped with Er3+/Yb3+ or Tm3+/Yb3+ lanthanide ions are efficient upconversion materials [1] that can find use in various technological fields, in particular in biomedical diagnostic. A recent paper describes the possibility of using upconverting Er3+/Yb3+ or Tm3+/Yb3+ codoped CaF2 nanoparticles for cellular imaging [2]. In this contribution, we describe the synthesis of water dispersible core-shell alkaline-earth fluoride nanoparticles and the study of the spectroscopic properties of the prepared nanostructures upon near infrared excitation. A hydrothermal procedure has been developed to prepare core-shell SrF2:Nd3+/Tm3+/Yb3+@SrF2:Nd3+ nanoparticles with hydrophilic capping agents. The behavior of the Tm3+ and Yb3+ ions luminescence upon excitation in the near infrared region and the Nd3+ - Yb3+ energy transfer processes have been investigated also as a function of the temperature for possible use of the nanoparticles as optical probes and nanothermometers. [1] M. Pedroni, F. Piccinelli, T. Passuello, S. Polizzi, J. Ueda, P. Haro-Gonzalez, L. M. Maestro, D. Jaque, J. Garcia-Sole, M. Bettinelli and A. Speghini, Cryst. Growth Des., 2013, 13, 4906-4913. [2] N. N. Dong, M. Pedroni, F. Piccinelli, G. Conti, A. Sbarbati, J. E. Ramirez-Hernandez, L. M. Maestro, M. C. Iglesias-de la Cruz, F. Sanz-Rodriguez, A. Juarranz, F. Chen, F. Vetrone, J. A. Capobianco, J. G. Sole, M. Bettinelli, D. Jaque and A. Speghini, ACS Nano, 2011, 5, 8665-8671.

Authors : Chris de Weerd, Katerina Dohnalova, Tom Gregorkiewicz
Affiliations : UvA-WZI

Resume : Although Si is widely used for photovoltaic and electronic applications, light emission from Si is in general poor due to its indirect bandgap. Apart from Si, also Ge makes a good candidate for electronic devices. It has a rather large exciton Bohr radius (~18 nm) and bulk Ge has a direct bandgap of 0.8 eV. Therefore, Ge should also make a good candidate for QD-based devices. As reported in past literature, emission from (oxidized) Ge QDs is in general weak. Here, we discuss high-intensity PL emission bands from colloidal butyl-terminated Ge QDs. The PL bands blueshift with increasing excitation energy, indicating an ensemble of QDs with a broad size distribution. We observed PL lifetimes on a sub-nanosecond timescale. In addition, we discuss the intraband transitions in butyl-terminated Ge QDs. For that purpose, we use ultrafast transient induced absorption spectroscopy. The time-dependent evolution of absorption spectra provides information on relaxation and recombination processes within the excited states of QDs. This is done by probing intraband transitions of free carriers generated by the pump pulse. We demonstrate that the features observed by experiment agree well with theoretical modeling. We discuss implications of these findings for new applications of these bright emitting colloidal Ge QDs for photovoltaic and light emitting devices.

Authors : Francesco Di Stasio, Joel Q. Grim, Angelo Accardo, Vladimir Lesnyak, Francesco De Donato, Iwan Moreels, Roman Krahne
Affiliations : Istituto Italiano di Tecnologia, Via Morego 30, IT-16163 Genoa, Italy

Resume : We discuss the optical properties of highly luminescent CdSe/CdS quantum dot-in-rods synthesized by seeded growth(1) and then transferred to water using a simple ligand-exchange method employing mercaptopropionic acid (MPA)(2). From a device fabrication point of view, water-soluble nanocrystals (NCs) are most desirable since they enable the preparation of multi-layer structures by exploiting orthogonal solvents, as well as the use of organic materials for the fabrication of a variety of photonic structures. Nevertheless, obtaining water-soluble CdSe/CdS NCs possessing similar optical properties to organic soluble ones has represented a major challenge. The water-soluble MPA-capped NCs here investigated possess a CdS rod with a diameter that is significantly larger than the CdSe core. The larger CdS rod prevents surface defects formed during the ligand-exchange reaction to affect the photophysics of the system, hence MPA-capped NCs show similar optical properties to the pristine (organic soluble) octadecylphosphonic acid functionalized NCs. More importantly, we demonstrate amplified spontaneous emission from the core or shell states(3) of films made from water-soluble CdSe/CdS dot-in-rods, providing further evidence that the desired properties are preserved after the ligand-exchange reaction. References: 1 Carbone L, et al. Nano Letters 2007, 7, 2942 2 Wuister S F, et al. Nano Letters 2003, 3 3 Krahne R, et al. Appl. Phys. Lett. 2011, 98, 063105

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nanoColloidal Hybrid Systems : Pascal André, Laurence Motte, Michel Calame
Authors : Michel Calame
Affiliations : Physics Department and Swiss Nanoscience Institute, University of Basel Klingelbergstrasse 82, 4056 Basel, Switzerland

Resume : Arrays of metal nanoparticles interlinked by an organic matrix have attracted a lot of interest due to their diverse electronic and optoelectronic properties [1]. By controlling the nature of the matrix material and the interparticle distance, the electronic behavior of the nanoparticle array can be substantially tuned and controlled [1,2]. We have recently shown that nanoparticle arrays form a useful architecture to build networks of molecular junctions. Here, the nanoparticles act as electronic contacts to the molecules and a molecular functionality can be used to induce an overall functionality at the array scale. Using this approach, we have build nanoarticles arrays exhibiting for instance redox [3] and optical [4] switching behaviors. The later is made possible thanks to the excitation of surface plasmons in the nanoparticles. Thanks to this particular configuration, the molecules can easily be accessed by optical means. A resonant excitation of the molecules within the array will thus leads to a photoconductance enhancement at the array level [5]. Nanoparticle arrays thus represent an interesting architecture opening possibilities for the development of novel molecular scale electronic and optoelectronic devices. Their possible implementation as an information storage platform or even as computing networks thanks to a defect‐tolerant architecture is currently under investigation [6]. References 1. M.A. Mangold et al., Nanoparticles arrays, to appear in the Springer Handbook of Nanoparticles (2014). 2. M. Calame, Molecular junctions: from tunneling to function, Chimia Int. J. Chem, 64 (6), 391‐397 (2010). 3. J. Liao et al., Cyclic conductance switching in networks of redox‐active molecular junctions, Nano Letters, 10 (3) , 759–764 (2010). 4. S. van der Molen et al., Light‐controlled conductance switching of ordered metalmolecule‐ metal devices, Nano Letters, 9 , 76‐80 (2009). 5. M. A. Mangold et al., Resonant Photoconductance of Molecular Junctions Formed in Gold Nanoparticle Arrays, J. Am. Chem. Soc., 133 (31) , 12185–12191 (2011). 6. G. Wendin et al., Synaptic Molecular Networks for Bio‐Inspired Information Processing, Int. J. Unconv. Comp., 8 , 325‐332 (2012).

Authors : E. Kalesaki, C. Delerue, C. Morais Smith, W. Beugeling, G. Allan, D. Vanmaekelbergh
Affiliations : IEMN-Department of ISEN, UMR CNRS 8520, 59046 Lille, France ; Physics and Materials Science Research Unit, University of Luxembourg, 162a avenue de la Faïencerie L-1511 Luxembourg, Luxembourg ; Institute for Theoretical Physics, University of Utrecht, 3584 CE Utrecht, Netherlands ; Debye Institute for Nanomaterials Science, University of Utrecht, 3584 CC Utrecht, Netherlands

Resume : Recent advancements in colloidal chemistry indicate that two-dimensional single-crystalline sheets of semiconductors forming a honeycomb lattice can be synthesized from semiconductor nanocrystals [1]. We perform atomistic tight-binding calculations of the band structure of CdSe sheets with such a nano-geometry [2]. We predict in the conduction band Dirac cones at two distinct energies and nontrivial flat bands and, in the valence band, topological edge states. These edge states are present in several electronic gaps opened in the valence band by the spin-orbit coupling and the quantum confinement in the honeycomb geometry. The lowest Dirac conduction band has s-orbital character and is equivalent to the pi bands of graphene but with renormalized couplings. The conduction bands higher in energy have no counterpart in graphene; they combine a Dirac cone and flat bands because of their p-orbital character. These systems emerge as remarkable platforms for studying complex electronic phases starting from conventional semiconductors. [1] W. H. Evers, B. Goris, S. Bals, M. Casavola, J. de Graaf, R. van Roij, M. Dijkstra, and D. Vanmaekelbergh, Nano Lett. 13, 2317 (2013). [2] E. Kalesaki, C. Delerue, C. Morais Smith, W. Beugeling, G. Allan, D. Vanmaekelbergh, Phys. Rev. X, in press.

Authors : B. van Dam, B. Bruhn, K. Dohnalova
Affiliations : Van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands

Resume : Silicon quantum dots (Si QDs) are promising alternative to toxic, rare and expensive QDs of other materials that nowadays are being researched for or used in optoelectronics, photonics and bio-imaging. Radiative rates, though, are comparatively low, owing to the indirect bandgap nature of Si. Deeper understanding of the processes involved can be achieved from single QD spectroscopy, allowing study of individual quantum emitters, while avoiding ensemble averaging effects. Comparison of single QD characteristics with those of the ensemble gives insight into the microscopic processes that underlie ensemble photoluminescence (PL) and quantum yield (QY). As generally in all quantum emitters, the QY is critically influenced by blinking (PL intermittency), a cyclic transition between an emissive bright and a non-radiative dark state, that emerges on a microscopic level. The mechanism behind the blinking process is not yet fully understood, but could arise from charging of the QD or trapping into a nearby defect state. Surface states assume a major role in both models, but also influence the radiative rates through modification of the electron and hole wavefunctions. By single QD spectroscopy, as well as complementary ensemble measurements, we examine the effect of carbon- and silica oxide-based surface capping on blinking and PL of colloidal Si QDs, which will help the development of Si QDs for application in lighting technologies.

Authors : Mireille Richard-Plouet, Luc Brohan, Hélène Terrisse, Solenn Berson*, Stéphane Guillerez *
Affiliations : Institut des Matériaux Jean Rouxel, Université de Nantes CNRS, 2, rue de la Houssinière, BP 32229, 44322 Nantes Cedex 03, France *CEA, LITEN, Laboratoire des Modules Photovoltaïques Organiques, INES 50 avenue du Lac Léman, 73375 Le Bourget du lac, France

Resume : The photoactive properties of titanium dioxide are very attractive allowing many applications in the environmental domains. Its integration in hybrid organic solar cells, especially, requires the elaboration of layers to optimize collection and transport of photogenerated electrons. Solvothermal process allows us to adjust the size and variety of titanium dioxide by tuning pH or by using organic solvents. Depending on the chosen way, the hydrolysis-condensation is controlled; sols, gels and crystalline colloids can be prepared. Choosing to perform the synthesis in suitable solvents is a key parameter to obtain colloidal solutions, with the required physico-chemical properties for chemical solution deposition. In order to remain compatible with low temperature processes on plastic substrates, crystalline colloids are processed as thin film because no further annealing at high temperature is required. Their integration as interfacial layers allowed us to lengthen the lifetime of organic bulk heterojunction solar cells over 6500 hours, with a loss in photon conversion efficiency limited to less than 17% [1]. [1] Karpinski, A.; Berson, S.; Terrisse, H.; Mancini-Le Granvalet, M.; Guillerez, S,; Brohan, L.; Richard-Plouet, M. Solar Energy Mater. & Solar Cells 116, 27-33, 2013

Emerging & Doped nanoColloids : Pascal André, Mathieu Maillard, Celso De Mello Donega
Authors : Celso de Mello Donega
Affiliations : Debye Institute for Nanomaterials Science, Utrecht University, Netherlands

Resume : Colloidal semiconductor nanocrystals (NCs) are a new class of versatile nanomaterials, whose properties are determined by their size, shape, and composition. Semiconductor NCs comprising two (or more) different materials joined together by heterointerfaces, i.e., heteronanocrystals (HNCs), offer even more exciting possibilities regarding property control. The spatial localization of charge carriers in HNCs can be manipulated by controlling the offsets between the energy levels of the materials that are combined at the heterointerface. Doping of NCs and HNCs enables further control over their electronic, optical, transport, and magnetic properties. Moreover, colloidal NCs and HNCs are coated with a layer of organic ligand molecules, which further extends their functionality, since it allows for easy surface manipulation and solution processing. These characteristics have turned colloidal semiconductor NCs and HNCs into promising materials for a myriad of applications, motivating extensive research into their synthesis. In this talk, we will discuss a synthesis approach that has been attracting increasing attention in recent years, and is establishing itself as a versatile strategy to fabricate shape-controlled NCs, HNCs, and doped NCs that are not attainable by conventional methods: Cation Exchange.

Authors : Paolo Dolcet[a], Maurizio Casarin[a], Silvia Gross[a,b]
Affiliations : [a] Dipartimento di Scienze Chimiche, Universit? degli Studi di Padova, via Marzolo, 1, I-35131, Padova, Italy; [b] Istituto per l?Energetica e le Interfasi, IENI-CNR and INSTM, UdR, via Marzolo, 1, I-35131, Padova, Italy

Resume : Colloidal systems are highly appealing to achieve a good control on inorganic nanoparticles size, size distribution, crystallinity and shape. Among them emulsions play a leading role and, in more detail, miniemulsions (MEs) represent a promising way to achieve a good control on the final material characteristics. Thanks to the high shear forces applied during homogenization, these systems reach the minimum droplet size possible, diffusion and collision phenomena are hindered, and droplets maintain their identity. A ME thus represents an ensemble of 1018-1020 independent droplets, where a reaction can take place in a parallel fashion. In these last years we exploited inverse MEs for the syntheses of a wide variety of inorganic materials. For example, ZnO nanostructures were obtained at RT, through an easy and reproducible route, which also enabled controlled doping (Eur. J. Inorg. Chem. 2013, 2291; J. Mater. Chem. 22, 1620). A similar approach was applied to the preparation of other lanthanide-doped binary and ternary systems, i.e., hydroxides, sulphides and halogenides. These materials showed good doping control, interesting luminescence properties and low cytotoxic effects, leading to appealing systems with potential bioimaging applications. The ME approach was also exploited for the photodecomposition in confined space of a tailored single-source Au/TiO2 precursor, enhancing catalytic properties with respect with the same materials prepared in a bulk (Nanoscale, 5, 10534).

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Authors : Katarzyna Matras-Postolek1, Karolina Gorka2, Michael Bredol2, Dariusz Bogdal1
Affiliations : 1Cracow University of Technology, Faculty of Chemical Engineering and Technology, Chair of Biotechnology and Physical Chemistry, Warszawska 24 St. 31-155 Cracow, Poland, e-mail: 2Münster University of Applied Sciences, Department of Chemical Engineering, Stegerwaldstraße 39, 48565 Steinfurt, Germany

Resume : In the last few years significant attention has been paid to the adjustment of optical properties of polymer nanocomposite materials by the employment of functionalized semiconductor inorganic nanocrystals (NCs). Zinc sulfide (ZnS) and zinc selenide (ZnSe) with band gap respectively about 3.6 eV and 2.8 eV are very good candidates as nanofillers for polymer systems because of their intense luminescence, narrow emission, broad absorption and chemical stability. Additionally, those materials due to the large band gap can be used as an efficient semiconductor hosts to dope different transition metal ions such as Mn2+. ZnS NCs doped with Mn2+ ion have been one of the best efficient electroluminescent phosphor materials in use. On the other hand, ZnSe NCs by having the smaller band gap is an attractive and suitable material for hybrid photovoltaic devices. In this work we report the fabrication and study of novel and transparent ZnSe:Mn/ZnS/PMMA and ZnS:Mn/PMMA hybrid nanocomposite thin films, including preparation techniques of colloidal ZnSe:Mn/ZnS and ZnS:Mn nanoparticles, their surface modification and the integration process with PMMA system in different solvents, as well as the consequences for their luminescence. Transparent ZnS:Mn/ZnS/PMMA and ZnS:Mn/PMMA nanocomposite materials via a film casting were obtained. Resulting colloidal nanocrystals and nanocomposite were characterized with respect to their optical and structural properties and their stability under ambient conditions. Additionally, in this work we present the latest research on preparation of one-dimensional (1D) ZnS and ZnSe NCs under microwaves irradiation and their surface modification as a potential component for polymer system.

Authors : Shanqing Zhang,[1]* Feng Peng [2]
Affiliations : [1] Centre for Clean Environment and Energy, Griffith School of Environment, Gold Coast Campus, Griffith University, QLD 4222 (Australia) ; [2] School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, Guangdong, 510640 (China)

Resume : A series of nanostructured TiO2 sensors and photoelectrochemical cells have been developed in our group for photoelectrochemical determination of organic compounds, leading to a series of commercialized patents [1] and commercial products. This sensing mechanism is based on photoelectrocatalytic oxidation of organic compounds in waters under UV radiation [2-4]. Recently, a hydrogenated nanostructured TiO2 photoanode was prepared by hydrogenating TiO2 nanorod arrays (H-TNRs) electrode. Hydrogenation is an efficient and effective means to extend light absorption to visible light region and improve electron conductivity of TiO2 via introduction of oxygen vacancy and mid-gap levels in TiO2 lattice. The H-TNRs photoanode was used as a sensor for organic compound detections under visible light illumination for the first time. Preliminary experiments demonstrate that the H-TNR electrode is able to sensitively determine various organic compounds in water with satisfactory stability. This suggests that the hydrogenation nanostructured TiO2 electrodes are promising in sensing organic compounds in waters and further to be further developed into commercial products. References: 1. Zhao, H., Zhang, S., Improved water analysis. PCT Int. Patent. (2008) WO 2008077191 2. Qiu J., Zhang S. , Zhao H., Recent Applications of TiO2 Nanomaterials in Chemical Sensing in Aqueous Media, Sensors & Actuators: B. Chemical, 2011, (2011); 160: 875-890 (Review) 3. Zhang S., Li H., Zhao H.,