The coloration of tungsten-oxide film by oxygen deficiency and its mechanism

Abstract The transmissivity and the optical absorption of a WO 3 film with oxygen deficiencies introduced were characterized and compared with those of an electrochromically colored WO 3 upon injecting a proton (H + ). The WO 3 film with oxygen deficiencies introduced was clearly colored blue. It was shown that the wavelength regions of optical absorption of both films almost overlapped each other.