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 MAPbCl₃/TiO₂ nanorods heterojunctions has been fabricated to overcome the shortcoming. The structure was composed of horizontal MAPbCl₃ polycrystalline and vertically aligned TiO₂ nanorods array. Many localized depletion regions at the MAPbCl₃/TiO₂ interface can reduce the dark current. The TiO₂/MAPbCl₃ 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/MAPbCl₃ heterojunction to fabricate high-performance UV detectors.