New nanocrystalline colored oxynitride thin films from Ti4+ -functionalized ZnO nanocolloids

International audienc

Covalent grafting of organic molecular chains on amorphous carbon surfaces

International audienceThe functionalization of amorphous carbon surfaces by organic monolayers has been performed using a low-temperature (120 °C) liquid-phase process. Linear undecylenic ester CH2CH(CH2)8COOC2H5 molecules are expected to form covalent CC bonds by reaction of alkene moieties with CH terminated surfaces. Amorphous carbon (a-C:H) films were grown using plasma decomposition of CH4 and graphite sputtering in ArH2. XPS data analysis provides a quantitative estimate of the density of covalently attached molecules (0.07-0.2 × 1015 cm−2) which is compared with the functionalization of H-passivated c-Si(1 1 1) surfaces

Assembly of Hexamolybdenum Metallic Clusters on Silicon Surfaces

International audienceBecoming attached: Mo6Ii8 (Ii=inner iodine) cluster cores are anchored in apical positions to monocrystalline silicon surfaces. The attachment occurs via pyridine groups, end-capping an alkyl monolayer which is covalently bound to the hydrogen-terminated silicon surface. Octahedral Mo6 clusters: orange; pyridine head groups of the monolayer: green; apical pyridine units: blue

Greffage de la transferrine sur oxyde de silicium

National audienc

From ZnO Colloids to Nanocrystalline Colored ZnxTiyOw-zNz Spinel Films

International audienceA new class of colored heterometallic ZnxTiyOw–zNz waveguides developed using a nanocolloidal sol–gel route combined with thermal treatment under ammonia atmosphere is reported. The resulting mesoporous layers are photostable and degrade the cationic pigment methylene blue under visible light irradiation. Semiconductor photocatalysis is currently being explored in environmental sciences, solar cell technologies, and preparative “green” technology

Covalent Immobilisation of Antibodies on Electrochemically Functionalized Carbon Surfaces

International audienc

Covalent Grafting of Organic Layers on Sputtered Amorphous Carbon: Surface Preparation and Coverage Density

The covalent attachment of ester-, pyridine-, and ferrocene-functionalized organic layers to amorphous carbon surfaces, grown by graphite sputtering in Ar-H2 mixtures, is reported. The surface modification is based on a low temperature (160 C) liquid-phase process. Thermally assisted grafting of linear alkenes is investigated by means of X-ray photoelectron spectroscopy (XPS), atomic force microscopy, and contact angle measurements. The beneficial role of surface oxygen removal by argon ion sputtering or thermal treatment prior to the ester grafting step is also discussed. Careful XPS data analysis provides a quantitative estimate of the density (0.2-4.3 × 1014 cm-2) of attached molecules as a function of surface preparation. The large packing density has been confirmed by the voltammetric response of a ferrocene-functionalized carbon surface

Electrochemical and Charge Transport Behavior of Molybdenum-Based Metallic Cluster Layers Immobilized on Modified n- and p-Type Si(111) Surfaces

International audienc

Tailoring the photoelectrochemistry of catalytic metal-insulator-semiconductor (MIS) photoanodes by a dissolution method

International audienceApart from being key structures of modern microelectronics, metal-insulator-semiconductor (MIS) junctions are highly promising electrodes for artificial leaves, i.e. photoelectrochemical cells that can convert sunlight into energy-rich fuels. Here, we demonstrate that homogeneous Si/SiO x /Ni MIS junctions, employed as photoanodes, can be functionalized with a redox-active species and simultaneously converted into high-photovoltage inhomogeneous MIS junctions by electrochemical dissolution. We also report on the considerable enhancement of performance towards urea oxidation, induced by this process. Finally, we demonstrate that both phenomena can be employed synergistically to design highly-efficient Si-based photoanodes. These findings open doors for the manufacturing of artificial leaves that can generate H 2 under solar illumination using contaminated water