A High-Performance UVA Photodetector Based on Polycrystalline Perovskite MAPbCl₃/TiO₂ Nanorods Heterojunctions

The application of TiO2 nanorods in the field of ultraviolet (UV) photodetectors is hindered by a high dark current, which is attributed to crystal surface defects and intrinsic excitation by carrier thermal diffusion. Here, a photodetector based on polycrystalline perovskite MAPbCl(3)/TiO2 nanorods heterojunctions has been fabricated to overcome the shortcoming. The structure was composed of horizontal MAPbCl(3) polycrystalline and vertically aligned TiO2 nanorods array. Many localized depletion regions at the MAPbCl(3)/TiO2 interface can reduce the dark current. The TiO2/MAPbCl(3) detector shows high performance including a high ratio of light-dark current of about six orders of magnitude, which is much larger than that of the TiO2 detector. This study indicates the potential in the TiO2/MAPbCl(3) heterojunction to fabricate high-performance UV detectors.