Capillary effects, wetting behavior and photo-induced tube filling of TiO2 nanotube layers

摘要

The present work addresses effects associated with the electrolyte penetration kinetics into TiO2 nanotube layers. In particular, it is shown that the electrolyte uptake kinetics affects the magnitude of the measured photoresponse. We demonstrate that for aqueous electrolytes the penetration of the electrolyte into a TiO2 nanotubular layer is comparably slow and may take up to several hours. The electrolyte uptake kinetics can significantly be accelerated by UV illumination. We ascribe this to a light-induced change in the wetting properties on the inside of the TiO2 nanotube surface. This effect can be exploited to achieve photo-induced filling of the nanotubes by a secondary material.