Ultraviolet-induced erasable photochromism in bilayer metal oxide films

摘要

We demonstrate that the optical transmittance of bilayer samples consisting of pyrolytically coated amorphous Mg-Sn-O and metal oxide films such as In2O3 and SnO2 decreases upon ultraviolet illumination, which can be recovered by annealing in air at ∼300℃. Spectral, structural, and compositional studies suggest that this photochromic phenomenon is induced by photoelectronic excitation in the Mg-Sn-O film, electron injection into the metal oxide, which becomes negatively charged, and subsequent formation of metallic particles, which absorb and/or scatter visible light.