Requirements for photochromism in double-layer metal oxide films

Abstract To reveal the photochromism (PC) in double-layer metal oxide films, we investigated reduction, considered to be the cause of PC, by XPS and confirmed reduction occurred near the interface. We synthesized various double-layer metal oxide films to investigate the conditions for PC and confirmed several showed PC than reported to date. From these results and consideration of the band structures of the systems, we suggest a mechanism for PC, involving electron movement through the interface and reduction of the interface by those electrons. Consequently, we found requirement about the electronic structure for PC to occur in double layer metal oxide.