High-Performance Ultraviolet Photovoltaic Detectors Based on Two-Dimensional Wide Bandgap PEA₂PbBr₄ Perovskite with...

The development of efficient and economic ultraviolet (UV) photodetectors is urgently required for many military and civil utilizations. Herein, we report on a UV photovoltaic-type detector utilizing a two-dimensional wide bandgap PEA₂PbBr₄ perovskite as the light-absorbing media. By introducing a MoO₃ thin layer to enhance hole transport and extraction, the photovoltage/photocurrent of the detector is improved, and the dark current is depressed simultaneously, rendering a significantly enhanced UV photoresponse. Remarkably, a UV self-driven detector constructed on a rigid substrate attains a high photovoltage responsivity of 6.58 × 10⁵ V/W, a large photocurrent responsivity of 182.3 mA/W, a respectable specific detectivity of 1.1 × 10¹² Jones, a rapid response speed of 16.2/26.2 ms, and a sizable linear dynamic range of 134 dB, upon 365 nm UV irradiation, along with a large UV/visible rejection ratio of 1047. Also, the above photoresponse parameters can reach 2.61 × 10⁵ V/W, 90.1 mA/W, 1.57 × 10¹¹ Jones, 17.4/27.5 ms, 119 dB, and 1021, for a device assembled on a plastic substrate. More importantly, both detectors exhibit ultralow dark currents on the order of pA, endowing them with the capability of sensing ultraweak UV light signals as low as 4.1 nW/cm². Plus, the flexible UV detector exhibited robust mechanical flexibility and bending durability. The utilization as a UV image sensor is demonstrated, as well. These UV photodetectors may find potential utilization in future UV optoelectronic systems.