Photovoltaic response enhancement of SrTiO3/TiO2 composite

A composite of SrTiO 3 /TiO 2 was successfully prepared using TiO 2 (Degussa P25) and SrTiO 3 powders as starting materials. The composite was characterized by X-ray diffraction (XRD), UV–vis absorption spectrum, scanning electron microscope (SEM), and surface photovoltage spectroscopy (SPS). The SrTiO 3 /TiO 2 composite presents an enhanced photovoltaic response compared with pure TiO 2 and SrTiO 3 . The enhancement was explained by investigating the energy levels of TiO 2 and SrTiO 3 , and the photoluminescence (PL) spectra of TiO 2 , SrTiO 3 and SrTiO 3 /TiO 2 . The analysis of energy levels shows that those of TiO 2 and SrTiO 3 are matching, which improves the separation efficiency of photogenerated carriers. The PL spectra indicate that the formation of SrTiO 3 /TiO 2 composite decreases the recombination rate of photogenerated carriers. Thus the photovoltaic response enhancement is mainly resulting from the improved separation efficiency and decreased recombination rate of photogenerated carriers for SrTiO 3 /TiO 2 composite.