SEMICONDUCTOR ELECTRODES .22. ELECTROCHROMISM AND PHOTOELECTROCHEMISTRY AT WO3 LAYERS PREPARED BY THERMAL AND ANODIC-OXIDATION OF W

Electrochromism was studied with WO3 layers prepared by thermal oxidation of W, and compared to the electrochromic behavior of other WO3 electrodes (anodic, amorphous, and annealed films). Although the WO3 layers obtained by thermal oxidation of W are crystalline, the electrochromic performance with this electrode is comparable to that of the evaporated amorphous WO3 electrode. The photoelectrochemical behavior of these electrodes, and in particular the effect of a pretreatment of repeated color-bleaching cycles, was also studied. Repeated color-bleaching cycles resulted in a significant improvement in the photoelectrolytic behavior of the WO3 layers. The photocurrent increased and the spectral distribution of the photocurrent shifted to longer wavelengths. The repeated color-bleaching cycles also cause a great improvement in the electrochromic behavior of the WO3 electrode as compared to that of the initially prepared electrode. © 1979, The Electrochemical Society, Inc. All rights reserved.