RF-SPUTTERED SNO2, SN-DOPED IN2O3 AND CE-DOPED TIO2 FILMS AS TRANSPARENT COUNTER ELECTRODES FOR ELECTROCHROMIC WINDOW

The SnO2, Sn-doped In2O3 and Ce-doped TiO2 films have been prepared by RF sputtering method, and their opto-electrochemical properties were investigated in view of the applicability as counter electrodes in the electrochromic window system. These oxide films could reversibly inte rcalate Li+ ions owing to the nanocrystalline texture, but remained co lorless and transparent. The high transmittance of the lithiated films could be attributed to the prevalence of the Sn4+/Sn2+ and Ce4+/Ce3redox couples having 5s and 6s character conduction bands, respectivel y. For the Ce-doped TiO2 film, (TiO2)(1-x)(CeO2)(x), an optimized elec trochemical reversibility was found in the film with the composition o f x=0.1.