A5009455306- Glass properties and applications
- Carbon Nanotubes in Composites
- High-pressure geophysics and materials
- Fullerene Chemistry and Applications
- Material Dynamics and Properties
- Phase-change materials and chalcogenides
- Mesoporous Materials and Catalysis
- Polyoxometalates: Synthesis and Applications
- Proteins in Food Systems
- Mechanical and Optical Resonators
- Silicone and Siloxane Chemistry
- Boron and Carbon Nanomaterials Research
- Nonlinear Optical Materials Studies
- Crystal Structures and Properties
- Building materials and conservation
- Geological and Geochemical Analysis
- Photonic Crystals and Applications
- Graphene research and applications
- Nanotechnology research and applications
- Mineralogy and Gemology Studies
- Chalcogenide Semiconductor Thin Films
- Aerogels and thermal insulation
- Acoustic Wave Resonator Technologies
- Solid-state spectroscopy and crystallography
- Luminescence Properties of Advanced Materials
Laboratoire Charles Coulomb
2014-2024
Université de Montpellier
2014-2024
Centre National de la Recherche Scientifique
2012-2024
Czech Academy of Sciences
2019
Czech Academy of Sciences, Institute of Physics
2019
University of Liège
2010
Institut Laue-Langevin
2010
Boston College
2010
Université Claude Bernard Lyon 1
2000-2006
Laboratoire d’Electrochimie et de Physico-chimie des Matériaux et des Interfaces
2006
The sol-gel preparation of a bridged silsesquioxane containing europium(III) salts and 2-thenoyltrifluoroacetone has been achieved from new ethane tetracarboxamide-based organosilane. Free-standing films with thicknesses up to 440 μm maximum absolute quantum yield (q) 0.34 ± 0.03 (excitation at 320 nm) were prepared by the drop cast method, while thin (∼200-400 spin-coated on glass substrates led highly luminescent coatings q = 0.60 0.02 345 nm). tested as planar solar concentrators...
The high-pressure behavior of polyiodides confined into the hollow core single-walled carbon nanotubes organized bundles has been studied by means Raman spectroscopy. Several regimes structural properties are observed for and under pressure. responses both compounds exhibit correlations over whole pressure range (0--17 GPa). Modifications, in particular, take place, respectively, between 1 2.3 GPa 7 9 nanotubes, depending on experiment. Differences one experiment to another discussed terms...
A hybrid system consisting of quaterthiophene derivative inserted into carbon nanotubes is studied. Encapsulation efficiency the conjugated oligomers in hollow core investigated by transmission electron microscopy and spatial-resolved energy loss spectroscopy. Infrared spectroscopy showed evidence a significant positive charge transfer on oligothiophene. Raman spectra display different behaviors depending excitation correlated to optical absorption energy. At high wavelength (far from...
We report an experimental study on the confinement of oligothiophene derivatives into single-walled carbon nanotubes over a large range diameter (from 0.68 to 1.93 nm). evidence by means Raman spectroscopy and transmission electron microscopy that supramolecular organizations confined oligothiophenes depend nanocontainer size. The radial breathing mode frequency is shown be monitored both number molecules nanotube section competition between oligothiophene/oligothiophene oligothiophene/tube...
We demonstrate that while the metastable face-centered cubic (fcc) phase of ${\mathrm{Ge}}_{2}{\mathrm{Sb}}_{2}{\mathrm{Te}}_{5}$ becomes amorphous under hydrostatic compression at about 15 GPa, stable trigonal remains crystalline. Upon higher compression, a body-centered is obtained in both cases around 30 GPa. decompression, retained for starting fcc initial structure recovered phase. argue presence vacancies and associated subsequent large atomic displacements lead to nanoscale separation...
In order to determine the influence of thermal history (fictive temperature) and OH content on elastic properties silica glass, we have investigated high resolution in situ Brillouin experiments SiO(2) glass from room temperature supercooled liquid at 1773 K across transition. The well known anomalous increase modulus glassy state regime is observed. No change slope moduli appears as a characteristic transition, contrast what happens various other glasses. We show that has weak effect...
In situ X-ray diffraction and Raman spectroscopy measurements of synthetic powdered samples faujasite 13X were carried out at high pressure using diamond anvil cells. Structural changes are detected, linked to a progressive reduction in crystallinity, before complete amorphization the material. Three distinct compressibility regions clearly observed, delimited by two discontinuities dependence volume around 2 3.5 GPa. The transition from crystal amorphous state is incomplete partially...
New one-dimensional (1D) hybrid nanosystems are elaborated with metalated or metal free phthalocyanine molecules encapsulated into the hollow core of single-walled carbon nanotubes. The X-ray diffraction experiments coupled to simulation allow evidencing 1D structural organization inside angle between molecule ring and nanotube axis is close 32° as determined from our density functional theory calculations. Confined display Raman spectra hardly altered respect bulk phase, suggesting a rather...
The molecular mechanism of Methyl Orange (MO) dye adsorption on the external surface Mg2Al–CO3 layered double hydroxide (LDH) was investigated by combining isotherms, X-ray diffraction, and infrared (IR) Raman spectroscopies coupled to DFT calculations. vibrational dynamic behavior upon organization were correlated with isotherm revealing a four-domain uptake mechanism. peculiar high capacity LDH toward MO explained surface-promoted aggregation over particles.
In the temperature range from room to about 150°C, prototypic phase-change material Ge2Sb2Te5 becomes amorphous upon hydrostatic compression. studied range, onset of amorphization is at 15GPa and completely amorphizes 25GPa; these values do not depend on temperature. Upon decompression, phase stable lower temperatures, yet higher temperatures (145°C), initial fcc recovered decompression. A possible mechanism pressure-induced its implications for memories are discussed.
Binary c–T phase diagrams of organogelators in solvent are frequently simplified to two domains, gel and sol, even when the melting temperatures display distinct regimes, an increase with T a plateau. Herein, diagram organogelator is elucidated by rheology, DSC, optical microscopy, transmitted light intensity measurements. We evidence miscibility gap between above threshold concentration, cL. In this domain or formation becomes monotectic transformation, which explains why corresponding...
Infrared response on a carbon nanotube is weak because this homonuclear allotrope of does not bear permanent dipoles. Here, we report the discovery an exaltation infrared absorption in single-walled nanotubes from dye molecule interactions. A study performed dimethylquaterthiophene confined into hollow core or π-stacked at outer surface latter leads to symmetry breaking, allowing us probe interactions between both subsystems. The nature these discussed taking account tube diameter. This new...
Selective study of intermolecular HBs with 2 types HB acceptor.
In this paper, small-angle x-ray scattering measurements are used to determine the different compressibility contributions, as well isothermal ${\ensuremath{\chi}}_{T}^{0}$ in thermal equilibrium silica glasses having histories. Using two methods of analysis, supercooled liquid and glassy state, we obtain, respectively, temperature fictive dependences ${\ensuremath{\chi}}_{T}^{0}$. The values obtained glass states very close each other. They agree with previous determinations literature....
Al1−xGaxPO4 solid solutions (x = 0.2, 0.3, 0.38, 0.7) and the pure AlPO4 0) GaPO4 1) end members with α-quartz-type structure were studied by Raman scattering. An investigation as a function of composition enabled various modes to be assigned, in particular coupled decoupled vibrations. The tetrahedral tilting modes, which have been linked high-temperature phase transitions β-quartz-type forms, found decoupled. In addition, it is shown that spectroscopy powerful technique for determining...
Density and concentration fluctuations have been investigated in a 3mol% GeO2 doped silica glass as function of the fictive temperature (the at which structure supercooled liquid has frozen-in to form glass) by small angle x-ray scattering measurements. The increase way is quite similar that observed for pure result density fluctuation dependence. Fluctuations also studied glasses containing different amounts up 21mol% GeO2. are shown very strongly with germanium amount strong increase. This...
The structure of glasses is characterized by the existence density and composition fluctuations on nanometre scale. We present three examples use small-angle X-ray scattering to get information about these fluctuations. thermal history OH content were observed have a huge influence. static compressibility decreases when or fictive temperature increase. showed that scanning can provide an accurate description position, width shape glass transition.
Vibrational dynamics in the corannulene crystal is exhaustively studied through Raman scattering, infrared spectroscopy, and inelastic neutron scattering. Experimental data are coupled to simulations of phonon modes performed framework first principle calculations. Intermolecular vibrations (libration translation) assigned low frequency domain (10–200 cm–1). These exhibit specific temperature dependence far-infrared.