Improved photochromism of WO<SUB>3</SUB> thin films by addition of Au nanoparticles

A WO₃/Au composite thin film is prepared by depositing gold nanoparticles onto the surface of a vacuum-evaporated WO₃ thin film through a spin-coating technique. It is found that the photochromism of the WO₃ thin films are enhanced greatly after the modification with Au nanoparticles. The enhancement effect is explained according to the Schottky barrier formed at the WO₃/Au interface and the surface effect of the gold nanoparticles. The results may be helpful in technical applications and provide a more detailed understanding of the photochromic mechanism.