Enhanced Detection and Stability Performance of Single‐Crystal Perovskite Detectors via Solvent‐Based Surface Treatments

Abstract Solution‐grown metal halide perovskite single crystals (MHP SCs) hold significant promise for applications in photodetection and high‐energy radiation detection. However, the detection performance and long‐term operational durability of single‐crystal perovskite detectors are hindered by surface defects. Conventional mechanical grinding and polishing methods are time‐consuming and labor‐intensive, and inevitably pose potential risks related to environmental pollution. In this work, a multiple solvent‐based surface engineering strategy is proposed to mitigate these issues. By utilizing the 1‐octadecene buffer layer and 1‐ethyl‐3‐methylimidazolium bromide (EMIMBr) ionic liquid passivation agent, the surface morphology is effectively improved and the surface defects of MAPbBr 3 single crystals (MPB SCs) are passivated. The treated MPB SCs demonstrate a substantial increase in photoluminescence intensity, nearly five times greater than that of the untreated samples, along with a prolonged PL lifetime. The photodetectors based on treated MPB SCs exhibit a suppressed dark current of 13.5 nA at a bias of 1 V, and improved response speed. Notably, after 110 days, the unencapsulated devices maintain reliable photodetection performance. Benefiting from suppressed leakage current noise, the planar radiation detectors with an Au/MPB SCs/Au device structure exhibit distinct response to 241 Am@5.49 MeV alpha particles at room temperature.