Photoelectrochemical properties of TiO2/SrTiO3 combined nanotube arrays

The TiO2/SrTiO3 combined nanotube structure was obtained by the anodization and hydrothermal process. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy, UV–vis absorption spectroscopy, etc. The behavior of photoelectrochemical activity in the combined films and pure TiO2 nanotube arrays had been investigated through photo-to-current conversion efficiency measurement. Compared with bare TiO2 electrodes, SrTiO3 modified TiO2 electrodes presented high charge transfer speed, high surface dominant photoelectrochemical response and photo-to-current conversion efficiency. The overall energy conversion efficiency was increased from 4.1% to 5.6% under the illumination of white light of 100 mW/cm2 by using N719 dye. It demonstrates that the formation of a composite structure on surface of TiO2 nanotubes plays an important role in the kinetic behaviors (like charge separation efficiency and electron transport rate) of the as-prepared DSSC cells. The mechanism for the enhancement of the photoelectrochemical activity is discussed.