Photovoltaic response enhancement of SrTiO3/TiO2 composite

Abstract: A composite of SrTiO3/TiO2 was successfully prepared using TiO2 (Degussa P25) and SrTiO3 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 SrTiO3/TiO2 composite presents an enhanced photovoltaic response compared with pure TiO2 and SrTiO3. The enhancement was explained by investigating the energy levels of TiO2 and SrTiO3, and the photoluminescence (PL) spectra of TiO2, SrTiO3 and SrTiO3/TiO2. The analysis of energy levels shows that those of TiO2 and SrTiO3 are matching, which improves the separation efficiency of photogenerated carriers. The PL spectra indicate that the formation of SrTiO3/TiO2 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 SrTiO3/TiO2 composite. [Copyright &y& Elsevier]