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

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.