High-Performance,\nSelf-Powered Photodetectors Based on Perovskite and Graphene

An\nideal photodetector must exhibit a fast and wide tunable spectral\nresponse, be highly responsive, have low power consumption, and have\na facile fabrication process. In this work, a self-powered photodetector\nwith a graphene electrode and a perovskite photoactive layer is assembled\nfor the first time. The graphene electrode is prepared using a solution\ntransfer process, and the perovskite layer is prepared using a solution\ncoating process, which makes the device low cost. Graphene can form\na Schottky junction with TiO₂ to efficiently separate/transport\nphotogenerated excitons at the graphene/perovskite interface. Unlike\nthe conventional photovoltaic structure, in this photodetector, both\nphotogenerated electrons and holes are transported along the same\ndirection to graphene, and electrons tunneled into TiO₂ are collected by the cathode and holes transported by graphene are\ncollected by the anode; therefore, the photodetector is self-powered.\nThe photodetector has a broad range of detection, from 260 to 900\nnm, an ultrahigh on–off ratio of 4 × 10⁶, rapid\nresponse to light on–off (<5 ms), and a high level of detection\nof ∼10¹¹ Jones. The high performance is primarily\ndue to the unique charge-transport property of graphene and strong\nlight absorption properties of perovskite. This work suggests a new\nmethod for the production of self-powered photodetectors with high\nperformance and low power consumption on a large scale.