Photointercalation effect of thin WO3 films

Abstract

It is shown that thin amorphous films of WO3 exhibit a photoinduced reversible coloration in an electrochemical cell of the form quartz/semitransparent Au/ethanol/WO3/In2O 3-coated glass. From measurements of the optical and electrical properties of the films, the coloration is attributed to the formation of H xWO3, presumably due to a photointercalation of protons into WO3 films. This effect is potentially useful for storage, learning, and modulation of two-dimensional optical information.