Cesium tin halide perovskite quantum dots for high-performance ultraviolet photodetectors

Lead halide perovskite quantum dots (QDs) have emerged as a class of photoelectric materials with excellent optical absorption and emission properties. However, the toxicity of lead ions seriously hinders their commercial applications. Herein, we successfully prepare lead-free perovskite CsSnX3 (X = Cl, Cl/Br, Br) QDs, and modulate the spectral properties through control of the anionic composition. Furthermore, the ultraviolet (UV) photodetectors with excellent performance are constructed using CsSnX3 (X = Cl, Cl/Br, Br) perovskite QDs, giving highly deep-UV sensitive photoconduction. The optimal D* of the device based on CsSnBr3 QDs is up to 1.27 × 1011 Jones at 365 nm, which benefits from the lowest defect density of CsSnBr3 QDs. This work provides a helpful approach to develop the high-performance UV photodetectors based on lead-free perovskite QDs.