A5061882537- Conducting polymers and applications
- Carbon Nanotubes in Composites
- Organic Electronics and Photovoltaics
- Graphene research and applications
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Gold and Silver Nanoparticles Synthesis and Applications
- Electrochemical Analysis and Applications
- Nanocluster Synthesis and Applications
- Diamond and Carbon-based Materials Research
- Fullerene Chemistry and Applications
- Molecular Junctions and Nanostructures
- Luminescence and Fluorescent Materials
- Mechanical and Optical Resonators
- Crystal Structures and Properties
- Nonlinear Optical Materials Research
- Mineralogy and Gemology Studies
- Magnetism in coordination complexes
- Ion-surface interactions and analysis
- Advanced Condensed Matter Physics
- Advancements in Battery Materials
- Analytical Chemistry and Sensors
- Lanthanide and Transition Metal Complexes
- Cultural Heritage Materials Analysis
- Geological and Geochemical Analysis
Institut des Matériaux Jean Rouxel
2016-2025
Nantes Université
2016-2025
Centre National de la Recherche Scientifique
2015-2024
Laboratoire de Physique des Gaz et des Plasmas
2010
Université Paris-Sud
2010
Université d'Angers
2008
Massachusetts Institute of Technology
2006
Argonne National Laboratory
2006
University of Cambridge
2006
Laboratoire d'Étude des Microstructures
2006
Single-wall boron nitride nanotubes samples synthesized by laser vaporization of a hexagonal BN target under nitrogen atmosphere are studied UV and visible Raman spectroscopy. We show that resonant conditions necessary for investigating phonon modes BNNTs. excitation in the (229 nm) provides preresonant conditions, allowing identification A1 tangential mode at 1370 cm-1. This is 5 cm-1 higher than E2g bulk h-BN. Ab initio calculations lower frequency h-BN with respect to large diameter...
Using surface-enhanced Raman scattering (SERS) and Fourier transform infrared (FTIR) spectroscopy, we show that composites based on polyaniline (PANI) single-walled carbon nanotubes (SWNTs) are different when they prepared by two methods: (1) adding dispersed SWNTs to the polymer solutions (2) chemical polymerization of aniline in presence SWNTs. The difference originates from irreversible transformation medium. synthesis medium used for preparation PANI transforms into fragments shorter...
Above a critical diameter, single- or few-walled carbon nanotubes spontaneously collapse as flattened nanotubes. Raman spectra of isolated and cylindrical have been recorded. The provokes an intense narrow D band, despite the absence any lattice disorder. curvature change near edge cavities activates framework continuity. Theoretical calculations based on Placzek approximation fully corroborate this experimental finding. Usually used tool to quantify defect density in graphenic structures,...
The manipulation of isolated single-wall carbon nanotubes (SWNTs), rather than bundles, has led to active research in the field functionalisation such compounds. Different ways exist today obtain some new soluble macromolecules from SWNTs. Here we focus on fluorination functionalisation. As solubility properties depend essentially degree functionalisation, it is important develop reliable and simple methods quantify this. CnF stoichiometry three different fluorinated SWNTs samples are...
A detailed characterization of covalently functionalized HiPco single-walled carbon nanotubes (SWNTs) has been carried out using several physicochemical methods (thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and Raman scattering). The chemical process, finally leading to SWNT−ester derivatives, starts from nitric acid purification pristine SWNTs. Besides the efficiency functionalization, we show that a loss metallic character is...
We recently synthesized new hybrid organic–inorganic sols and gel obtained by the slow hydrolysis of N,N-dimethylformamide (DMF) TiOCl2 acidic solution. The comprehension synthesis mechanism these materials, made up Ti–O framework surrounded organic molecules, is important to understand their original photochemical properties. use Raman spectroscopy provides information on role DMF for complexation Ti4+ its subsequent in dimethylammonium chloride (DMACl) methanoate species during...
Single-wall carbon nanotubes (SWCNTs) are fluorinated around 200 °C with molecular fluorine (F2) and xenon difluoride (XeF2) as fluorination agents. In this latter case, is carried out by atomic F• generated the thermal decomposition of gaseous XeF2 on nanotube surface. treatment results in stoichiometries from CF0.05 to CF0.32, F2 gives compositions range CF0.04 CF0.37. Transmission electronic microscopy (TEM), solid state Nuclear Magnetic Resonance (NMR), Raman scattering Optical...
Hollow bimetallic nanostructures are of great importance for various applications. Understanding the fundamental mechanisms occurring during synthesis such nanomaterials by wet chemistry remains very challenging. This Article reports a mechanistic study on galvanic replacement reaction between planar arrays silver nanowires grown site-specifically tall silicon nanogratings and HAuCl4 in lack any stabilizing or capping agent, which might complicate alter conversion process into silver–gold...
In the field of stimuli-responsive luminescent materials, mechanochromic compounds exhibiting reversible emission color changes activated by mechanical stimulation present appealing perspectives in sensor applications. The luminescence properties molecular cubane copper iodide cluster [Cu4I4[PPh2(C6H4–CH2OH)]4] (1) are reported this study. This compound can form upon melting an amorphous phase, giving unprecedented opportunity to investigate mechanochromism phenomenon. Because mechanically...
Abstract The nature of pigments in naturally colored pearls is still under discussion. For this study, Raman scattering measurements were obtained for 30 untreated freshwater cultured from the mollusk Hyriopsis cumingi covering their typical range colors. originality work that seven different excitation wavelengths (1064 nm, 676.44 647.14 514.53 487.98 457.94 363.80 nm) are used same samples at highest possible resolution. All show two major features polyenic compounds assigned to double...
Fifteen opal samples of gem quality from the Spencer Opal Mines in Idaho (USA) were examined. These opals display play-of-colour, with three them having a pink body colour. The analysis was conducted using standard gemmological tools, along non-destructive spectroscopic, chemical, and imaging methods. All identified as opal-A, their play-of-colour resulting regular stacking hydrated silica spheres. However, at times, spheres are large to allow diffraction. Opal-A only occasionally found...
Solid state Raman and IR spectra of [(η2-dppe)(η5-C5Me5)Fe(CC–C6H4–X)n+][PF6−]n (n = 0, 1; dppe 1,2-(diphenylphosphino)ethane; X NO2, CN, CF3, F, Br, H, Me, tBu, OMe, NH2) complexes (1a–j/[1a–j+][PF6−]) were recorded. The are discussed in connection with the corresponding solid spectra. In present set compounds, allows a firm identification νCC stretching modes confirms occurrence Fermi coupling some substituents given oxidation state. Linear correlations between frequencies or square roots...
We demonstrate a facile fabrication of gold nanostructures including Au nanoplates (NPs), nanothorns (NTs), and nanowires (NWs) on indium tin oxide substrates via electrochemical growth. A simple two-electrode deposition system was applied for the process. Dense were grown directly an seeding layer substrate. After 48 h, NPs 2−5 μm in width 150−200 nm thickness. The NTs 1−3 height, 300−500 bottom side width, 20 at apex. NWs 30−80 diameter about length. entire process template-free...
A mechanochromic luminescent copper iodide cluster is reported whose luminescence exalted in response to mechanical stress. The underlying mechanism has been investigated along with the preparation of mechanically responsive films.
Surface-enhanced Raman scattering (SERS) has proved to be an effective technique for studying the structural properties of conducting polymer thin films. The enhancement process a twofold origin, electromagnetic and chemical. enhancement, which is dominant mechanism in SERS generation, consists excitation localized delocalized surface plasmons (SPs) metallic support film. emission adsorbed molecules on metal (the most efficient being Ag, Au Cu) due intense evanescent field located at...
Scanning electron microscopy, Raman scattering, UV–VIS absorption spectroscopy and low temperature photoluminescence (PL) were used to examine small particles produced by the chemical reaction between Pb(NO3)2 KI in different liquid media: water, methanol, ethanol acetonitrile. By stoichiometric changes synthesis reaction, platelets of PbI2 rods probably KPbI3 are produced. Regardless shape size, these exhibit almost same PL, which consists two intense bands centred around 2.5 (E band) 2.0...
We present a systematic Raman study over range of excitation energies arc discharge single-walled carbon nanotubes (SWCNTs) covalently functionalized according to two processes, esterification and reductive alkylation. The SWCNTs are characterized by resonance spectroscopy at each step the functionalization process, showing changes in radial breathing mode frequencies transition for both semiconducting metallic tubes. Particular attention is given family tubes clearly identified Kataura plot...
This paper demonstrates the use of surface plasmon resonance core-shell Ag@TiO2 particles in SHINERS experiments. A copper(ii) complex grafted onto was probed by Raman spectroscopy using excitation profiles vs. wavelengths (514, 633 and 785 nm) to tune signals. Enhancement factors assembly have been estimated compared SERS effect unmodified silver NPs colloidal dispersions. Finally, grafting advantageously Ag@SiO2 shell.
Polycrystalline samples of Mn1-xCuxWO4 (x ≤ 0.5) have been prepared by a solid-state synthesis as well from citrate at moderate temperature (850 °C). The goal is to study changes in the structural, magnetic, and dielectric properties magnetoelectric type-II multiferroic MnWO4 caused replacing Jahn-Teller-inactive Mn(2+) (d(5), S = 5/2) ions with Jahn-Teller-active Cu(2+) (d(9), 1/2) ions. Combination techniques including scanning electron microscopy, powder X-ray neutron diffraction, Raman...