Abstract
Electrochromism of tungstic oxide films were investigated. The films were prerared by r. f. sputtering from compressed WO3 target under various total pressure and O2 content of Ar-O2 mixed sputtering atmosphere. Blue films were obtained under low total pressure of sputtering atmosphere with low content of O2. These films could be colored more deeply by the conventional electrochemical procedure, but could not be bleached to transparent states. Transparent films were obtained under the condition of high total pressure or high O2 content of sputtering atmosphere. The transparent films prepared under high pressure show good electrochromic behavior after aging process. During the aging process, “passive protons” are injected into WO3 matrix, where the “passive proton” means that it has no influence on electrochromic absorption band, and is not able to be extracted electrochemically.
