Electrochromic switching with nanocrystalline TiO2 semiconductor films

Forward biasing of transparent nanocryst. TiO2 (anatase) films in Li ion contg. org. electrolytes leads to rapid and reversible coloration due to electron accumulation and Li+ intercalation in the anatase lattice. Absorption of > 90% light throughout the visible and near IR can be switched on and off within a few seconds. The nanocryst. morphol. of the film plays a primordial role in enhancing the electrochromic process. Preliminary results from the redn. of a surface attached viologen mol. leading to a blue coloration of the film are reported.