Investigation on gasochromic properties of tungsten oxides using ion irradiation

Takano, Katsuyoshi; Inoue, Aichi; Yamamoto, Shunya; Sugimoto, Masaki; Miyashita, Atsumi; Yoshikawa, Masahito; Sugiyama, Akira; Nagata, Shinji*

To improve the gasochromic coloration, ion irradiations with He at 350 keV for tungsten tri-oxide (WO) films were performed. The coloration was improved by the irradiations with the fluence of 110 ions/sm, as that the extent of coloration level is 7.5 times lager than that of non-irradiated film. In the irradiated films, it is estimated from the fitting analysis for W 4 photoemission spectra that 20 % of the oxygen in the film defects due to the irradiation. And then, it is found from X-ray diffraction measurements the distance of (100) planes in monoclinic phase is expanded to 2 %. The improvement of the gasochromic coloration of the irradiated WO films relates to the increment of oxygen defects induced by the irradiation, through the distortion of crystal structure.