Ultra‐Stable and Sensitive Ultraviolet Photodetectors Based on Monocrystalline Perovskite Thin Films

Abstract The detection of ultraviolet (UV) radiation with effective performance and robust stability is essential to practical applications. Metal halide single‐crystal perovskites (ABX 3 ) are promising next‐generation materials for UV detection. The device performance of all‐inorganic CsPbCl 3 photodetectors (PDs) is still limited by inner imperfection of crystals grown in solution. Here wafer‐scale single‐crystal CsPbCl 3 thin films are successfully grown by vapor‐phase epitaxy method, and the as‐constructed PDs under UV light illumination exhibit an ultralow dark current of 7.18 pA, ultrahigh ON/OFF ratio of ≈5.22 × 10 5 , competitive responsivity of 32.8 A W −1 , external quantum efficiency of 10867% and specific detectivity of 4.22 × 10 12 Jones. More importantly, they feature superb long‐term stability toward moisture and oxygen within twenty‐one months, good temperature tolerances at low and high temperatures. The ability of the photodetector arrays for excellent UV light imaging is further demonstrated.