Demonstrative experiments about gold nanoparticles and nanofilms: an introduction to nanoscience

International audienceAn important task of the scientific community is to provide non-specialized audience with explanations about what is nanoscience. Such explanations can be given during public conferences, seminars in high schools or lab work organized with teachers. And very often, the use of an experimental illustration greatly helps to raise the interest and the curiosity of the public. The present article will describe how the authors have used five simple and visual experiments in chemistry and physics to progressively introduce different audiences into the fascination of nanoscience. One experiment is the synthesis of gold nanoparticles with the Turkevich method and shows the progressive appearance of the ruby-red colour of the nanometric gold particles. The second and third experiments describe the way for modulating their colour and how to include them into a polymer and form a ruby-red coloured plastic film. The fourth experiment shows that starting from these nanoparticles, it is possible to turn them back into a yellow golden film. The last experiment is based on the optical properties of ultra-thin gold films. Using the plasmon resonance, it is possible to demonstrate that gold change colours from yellow to orange and green when a white light beam is shone on the gold interface. These visual experiments cannot be fully interpreted in front of a large audience but serve for rising curiosity

Electron Tunneling in Ferritin and Associated Biosystems

Ferritin is a 12 nanometer (nm) diameter iron storage protein complex that is found in most plants and animals. A substantial body of evidence has established that electrons can tunnel through and between ferritin protein nanoparticles and that it exhibits Coulomb blockade behavior, which is also seen in quantum dots and nanoparticles. This evidence can be used to understand the behavior of these particles for use in nanoelectronic devices, for biomedical applications and for investigation of quantum biological phenomena. Ferritin also has magnetic properties that make it useful for applications such as memristors and as a contrast agent for magnetic resonance imaging. This article provides a short overview of this evidence, as well as evidence of ferritin structures in vivo and of tunneling in those structures, with an emphasis on ferritin structures in substantia nigra pars compacta (SNc) neurons. Potential biomedical applications that could utilize these ferritin protein nanoparticles are also discussed.</p

Al4SiC4 w\"urtzite crystal: structural, optoelectronic, elastic and piezoelectric properties

New experimental results supported by theoretical analyses are proposed for aluminum silicon carbide (Al4SiC4). A state of the art implementation of the Density Functional Theory is used to analyze the experimental crystal structure, the Born charges, the elastic and piezoelectric properties. The Born charge tensor is correlated to the local bonding environment for each atom. The electronic band structure is computed including self-consistent many-body corrections. Al4SiC4 material properties are compared to other wide band gap W\"urtzite materials. From a comparison between an ellipsometry study of the optical properties and theoretical results, we conclude that the Al4SiC4 material has indirect and direct band gap energies of about 2.5eV and 3.2 eV respectively.Comment: 10 pages, 4 figure

Vibrational properties of SrCu2O2 studied via Density Functional Theory calculations and compared to Raman and infrared spectroscopy measurements

International audienceThe SrCu2O2 material is a p-type transparent conductive oxide. A theoretical study of the SrCu2O2 crystal is performed with a state of the art implementation of the Density Functional Theory. The simulated crystal structure is compared with available X-ray diffraction data and previous theoretical modeling. Density Functional Perturbation Theory is used to study the vibrational properties of the SrCu2O2 crystal. A symmetry analysis of the optical phonon eigenvectors at the Brillouin zone center is proposed. The Raman spectra simulated using the derivatives of the dielectric susceptibility, show a good agreement with Raman scattering experimental results

Investigation of the adsorption of 4-cyanopyridine on Au(111) by in situ visible-infrared sum frequency generation

We have investigated the configuration of 4-cyanopyridine on Au(111) electrodes in perchlorate solution by in situ visible–IR sum frequency generation (SFG). Thanks to the use of two IR tunable lasers (the free electron laser CLIO and a table laser based on an optical parametric oscillator) we have obtained SFG spectra of the system in the spectral range of both the aromatic cycle and the CN stretching modes. We present herein the first SFG spectra ever obtained under electrochemical conditions in the 9–12 μm range. Our results show a potential-dependent orientation of the adsorbed 4-cyanopyridine from a configuration where the molecule is adsorbed perpendicular to the electrode via the nitrogen of the pyridine ring at negative potentials, to a flat adsorption configuration at intermediate potentials, and finally a perpendicular orientation again where the molecule is bound through the nitrogen of the cyanide end

Welcome to the world of nanometric gold!,Bienvenue dans le monde de l'or nanométrique !

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ETUDE PAR SPECTROSCOPIE NON LINEAIRE SFG ET DFG DE L'ADSORPTION DE LA 4-CYANOPYRIDINE SUR DES ELECTRODES D'OR

ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Welcome to the world of nanometric gold!,Bienvenue dans le monde de l'or nanométrique !

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Nanoparticules d’or pour susciter des rencontres entre science et société

International audienceEn raison de sa couleur et de ses propriétés de métal noble, l’or a depuis toujours été un élément de fascination et de convoitise. Des démonstrations avec des nanoparticules d’or se prêtent bien aux actions de formation et de dissémination des sciences. Des expériences faciles et ludiques peuvent montrer au grand public comment les propriétés changent à l’échelle nanométrique avec la taille et la forme et expliquer les applications des nanoparticules d’or dans plusieurs domaines. Différentes actions ont été menées par des scientifiques de la Société Chimique de France, de la Société Française de Physique, des C’Nano ou du GDR Or-Nano pour proposer des ateliers destinés à présenter les nanoparticules d’or et introduire les nanosciences au sein des lycées ou des universités, dans des expositions ou des musées. Ce partage de connaissances permet d’informer le grand public, de susciter des curiosités et parfois même des vocations chez les plus jeunes. Pour le chercheur, les actions de dissémination lui permettent à travers la communication et les échanges d’aller au-delà de ses propres recherches, et l’amènent parfois à de nouvelles interrogations

An Introduction to Plasmonics

The book is intended for academia: university, college and engineering schools. Specially suited for graduate students in physics, materials science or chemistry. Also useful for PhD students and researchers entering the field of plasmonics as well as undergraduate courses in physics and electromagnetism.International audienc