ELECTROCHROMIC BEHAVIOR OF WO_3, TiO_2, AND COMPOSITE WO_3-TiO_2 FILMS PREPARED BY PULSED ELECTRODEPOSITION

摘要

This study builds upon on an earlier communication from our group [Electrochem. Commun. 5, 220 (2003)] that described the preparation, by pulsed cathodic electrodeposition, of WO_3-TiO_2 composite films over a wide compositional range. We focus here on their electrochromic behavior. It is shown that the progressive coloration of an initially transparent conducting oxide glass substrate, as a result of oxide film growth, offers a versatile spectroelectrochemical probe of the film electrosynthesis process itself. Finally, both the blue shift undergone by the absorption threshold of the oxide film (as a result of electron accumulation during the electrochromic process), and the coloration dynamics are favorably influenced by the presence of small amounts of TiO_2 in the WO_3 film.