engleski

SAXS characterization of mesoporous thin films: A solar energy point of view

Nanostructured materials are hierarchically structured on different length scales down to the atomic or grain size level. Electromagnetic radiation can be used to obtain information about materials with dimensions of the same order as the radiation wavelength. Small-angle X-ray scattering (SAXS) experiments generally fulfil these requirements ; irradiate a sample with X-rays, measure the resulting scattering pattern, then determine the structure that caused the observed pattern. SAXS is used to explore microstructure on the nanometer scale. Grazing-incidence X-ray reflectivity (GIXR) can provide detailed information about the thickness of single layer, multilayer periodicity and thickness of the individual layers that make up a multilayer. The full potential of these techniques is realised when using a synchrotron source and when patterns are recorded with two-dimensional detectors. Titanium dioxide, titanium oxide based gels, cerium dioxide and Ce/Sn oxide films, vanadium oxide and V/Ce oxide films on a glass substrate were obtained by sol-gel process. The hydrogenated amorphous silicon and silicon carbide thin films were deposited by magnetron sputtering and PECVD (Plasma Enhanced Chemical Vapour Deposition) in a wide range of hydrogen and carbon concentration. Mesostructured titanium and vanadium-oxo-based films and lamellar structure of silica/organic nanocomposite were prepared by evaporation induced self-assembly. All these materials are potential electrodes and active elements in new generation of solar cells. The structure, morphology and phase transitions of these nanostructured and mesoporous films were studied by synchrotron radiation SAXS and grazing-incidence small-angle X-ray scattering (GISAXS). Layer structure in V/Ce oxides was revealed by grazing-incidence X-ray reflectivity (GIXR) method.

SAXS, GISAXS/GIXR, Nanostructures, Nanocomposites

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