A RAMAN MICROPROBE STUDY OF THE ELECTROCHROMIC AND PHOTOCHROMIC THIN-FILMS OF MOLYBDENUM TRIOXIDE AND TUNGSTEN TRIOXIDE

Raman microprobe spectroscopy has been used to study the electrochromi c thin films of MoO3 and WO3. It was found that the MoO3 thin films, a fter subjecting to cathodic polarization or UV irradiation, exhibited several Raman peaks at 112, 124, 150, 283, 336, 376, 663, 820 and 994 cm-1 which could be ascribed to those of crystalline MoO3. The presenc e of these Raman peaks suggested that the MoO3 films had transformed f rom a disordered amorphous state to a more ordered crystalline state. In contrast, no improvement in the crystallinity of the WO3 thin films was evident when they had undergone similar electrochromic and photoc hromic processes.