Enhanced photochromism of Ag loaded self-organized TiO2 nanotube layers

The present work investigates the photochromic behavior of Ag nanoparticles loaded onto self-organized TiO2 nanotube layers grown by anodization of Ti in fluoride containing electrolytes. Ag nanoparticles (similar to 10 nm) were deposited photocatalytically on the layers. These Ag/TiO2 structures show considerable photochromic activity in the visible range. Optical images and reflectance spectra show that the Ag loaded nanotubes have much higher photochromic contrast than the Ag loaded compact TiO2 layers. Significantly increased switching speed is observed for the Ag loaded nanotubes, with a faster kinetics for the longer nanotubes. These photochromic effects are significantly stronger for amorphous nanotubes than for crystalline anatase nanotubes. (C) 2007 Elsevier B.V. All rights reserved.