2.1. Solvents 4307 2.1.1. Propylene Carbonate (PC) 4308 2.1.2. Ethers 4308 2.1.3. Ethylene Carbonate (EC) 4309 2.1.4. Linear Dialkyl Carbonates 4310 2.2. Lithium Salts 4310 2.2.1. Lithium Perchlorate (LiClO4) 4311 2.2.2. Lithium Hexafluoroarsenate (LiAsF6) 4312 2.2.3. Lithium Tetrafluoroborate (LiBF4) 4312 2.2.4. Lithium Trifluoromethanesulfonate (LiTf) 4312 2.2.5. Lithium Bis(trifluoromethanesulfonyl)imide (LiIm) and Its Derivatives 4313

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Nonaqueous liquid electrolytes for lithium-based rechargeable batteries.

Color Control in π-Conjugated Organic Polymers for Use in Electrochromic Devices

Despite the recent developments in graphene oxide due to its importance as a host precursor of graphene, the detailed electronic structure and its evolution during the thermal reduction remain largely unknown, hindering its potential applications. We show that a combination of high-resolution in situ X-ray photoemission and X-ray absorption spectroscopies offer a powerful approach to monitor the deoxygenation process and comprehensively evaluate the electronic structure of graphene oxide thin films at different stages of the thermal reduction process. It is established that the edge plane carboxyl groups are highly unstable, whereas carbonyl groups are more difficult to remove. The results consistently support the formation of phenol groups through reaction of basal plane epoxide groups with adjacent hydroxyl groups at moderate degrees of thermal activation (∼400 °C). The phenol groups are predominant over carbonyl groups and survive even at a temperature of 1000 °C. For the first time, a drastic increase...

Probing the Thermal Deoxygenation of Graphene Oxide Using High-Resolution In Situ X-ray-Based Spectroscopies

Amorphous molybdenum sulfide films are efficient hydrogen evolution catalysts in water. The films are prepared via simple electro-polymerization procedures and are characterized by XPS, electron microscopy and electronic absorption spectroscopy. Whereas the precatalysts could be MoS3 or MoS2, the active form of the catalysts is identified as amorphous MoS2. Significant geometric current densities are achieved at low overpotentials (e.g., 15 mA cm−2 at η = 200 mV) using these catalysts. The catalysis is compatible with a wide range of pHs (e.g., 0 to 13). The current efficiency for hydrogen production is quantitative. A 40 mV Tafel slope is observed, suggesting a rate-determining ion+atom step. The turnover frequency per active site is calculated. The amorphous molybdenum sulfide films are among the most active non-precious hydrogen evolution catalysts.

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Amorphous molybdenum sulfide films as catalysts for electrochemical hydrogen production in water

Tin doped indium oxide (ITO) films are highly transparent in the visible region, exhibiting high reflectance in the infrared region, and having nearly metallic conductivity. Owing to this unusual combination of electrical and optical properties, this material is widely applied in optoelectronic devices. The association of these properties in a single material explains the vast domain of its applicability and the diverse production methods which have emerged. Although the different properties of tin doped indium oxide in the film form are interdependent, this article mainly focuses on the electrical aspects. Detailed description of the conduction mechanism and the main parameters that control the conductivity is presented. On account of the large varieties and differences in the fabrication techniques, the electrical properties of ITO films are discussed and compared within each technique.

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Tin doped indium oxide thin films: Electrical properties

The electron yield at atmospheric pressure for X ray absorption spectroscopy is a new technique able to study the very top surface of thick samples in real environments. A combined detector has been designed at LURE which yields spectra in transmission, electron and fluorescence modes. This method offers, compare to the surface EXAFS technique, several advantages : i) possibility of studying directly thick samples without any specific preparation, ii) simplicity of the technology which does not require ultra-high vacuum and iii) high sensitivity due to the large solid angle collection. The probed thickness with this configuration is typically of the order of 300-500A which means that thin films, implanted materials or interfaces can be studied ; preliminary results on such systems are reported.

Electron yield X ray absorption spectroscopy at atmospheric pressure

High-pressure properties of krypton were investigated by energy-dispersive extended x-ray absorption fine-structure spectroscopy in a diamond anvil cell at room temperature. The equation of state agrees very well with x-ray diffraction data. The pressure dependence of the Debye-Waller factor was determined and compared with calculations using pair potentials. The analysis of the x-ray absorption near-edge structure part of the spectrum shows the possibility of measuring the pressure in bubbles of krypton implanted in metallic matrices.

X ray absorption spectroscopy on solid krypton up to 20 GPa

A significant dependence of polyacrylonitrile films NEXAFS spectral characteristics measured on samples differing by their configurational properties is reported. The dominant effect results from a modification of the splitting of the two C≡N π * levels with the isotacticity percentage of the chains. This observation opens the prospect of using near edge X-ray absorption fine structure technique to get information on the configurational properties of polymer chains in situations where otherwise more adapted technique cannot be used

Preliminary NEXAFS study of polyacrylonitrile samples differing by their isotacticity percentages

Electronic structure and orientation studies of undoped poly3alkylthiophenes electrochemically deposited on Pt as studied by NEXAFS

La technique d'absorption X en mode dispersif associee a un detecteur a localisation (barrette de photodiodes) permet d'obtenir des spectres en un temps minimum de 4 ms. De nombreuses etudes cinetiques ont ete realisees avec ce systeme. Deux exemples sont developpes: oxydoreduction d'une electrode d'hydroxyde de nickel et oxygenation et desoxygenation des supraconducteurs haute temperature

Gérard Tourillon

Papers

Electron yield X ray absorption spectroscopy at atmospheric pressure

X ray absorption spectroscopy on solid krypton up to 20 GPa

Preliminary NEXAFS study of polyacrylonitrile samples differing by their isotacticity percentages

Electronic structure and orientation studies of undoped poly3alkylthiophenes electrochemically deposited on Pt as studied by NEXAFS

Spectroscopie résolue dans le temps : études cinétiques in situ de différentes réactions chimiques