GASOCHROMIC EFFECT IN PLATINUM-DOPED TUNGSTEN TRIOXIDE FILMS PREPAREDBY THE SOL-GEL METHOD

Tungsten oxide doped by a complex of platinum exhibits a gasochromic e ffect. A reversible coloration is observed on successive exposure to h ydrogen and air. The films were prepared by the sol-gel method at room temperature. They showed strong darkening (blue color) on exposure to hydrogen and were bleached completely when exposed to air. The proces s has been reproduced completely hundreds of times without any losses. The cycling of the coloration was obtained from W-Vis spectra and the mechanism deduced from both visible and Fourier transform infrared (F TIR) spectra. Colorimetric properties of the gasochromic films were ex pressed in color space chromaticity diagram.