High‐Gain and Low‐Driving‐Voltage Photodetectors Based on Organolead Triiodide Perovskites

Solution-processed organometal trihalide perovskite photodetectors show a high photoconductive gain of above 400 across the UV to NIR range at a very low bias of −1 V. The charge traps caused by large concentrations of Pb2+ cations at the top surface of the perovskite film are critical for achieving high gain in these devices via a trapped-hole-induced electron injection mechanism.