A facile method to synthesize two-dimensional CsPb₂Br₅ nano-/micro-sheets for high-performance solution-processed photodetectors

In this paper, a facile method to synthesize two-dimensional (2D) all-inorganic CsPb₂Br₅ nano-/micro-sheets at room temperature and their application as the active layer in solution-processed high-performance photodetectors are presented. The obtained CsPb₂Br₅ nano-/micro-sheets showed a photoluminescence emission peak at 522 nm with a narrow full-width-at-half-maximum of ∼17 nm, showing its high color purity, and an absorption peak at 307 nm with a shoulder peak at 339 nm. Then, the obtained CsPb₂Br₅ nano-/micro-sheets were used as the active layer in photoconductive photodetector and a high specific detectivity of 1.0 × 10¹² Jones with a photoresponsivity of 0.02 A/W and an ultra-low dark current of ∼10⁻¹² An under 16 μW/cm² 405 nm illumination were obtained from photoconductive photodetector Au/CsPb₂Br₅(85 μm)/Au. Further, the physical mechanism for the enhanced performance is discussed. Therefore, it provides a new method to suppress dark current for high-performance CsPb₂Br₅ photodetectors.