Defect Passivation and Energy Level Modulation of CsPbBr_2I QDs for High-Detectivity and Stable Photodetectors

摘要

High-detectivity and stable photodetectors (PDs) have been intensively concernedin the field of wireless optical communication, among which perovskitematerial has become a prospective candidate owing to its outstandingphotoelectric properties. However, the defects and mismatched energy levelsof perovskite material can significantly reduce the detectivity and stability ofPDs. Herein, the CsPbBr_2I quantum dots (CQDs) with the surface modulationvia potassium trifluoroacetate (KTFA) are utilized to deserve high-detectivityand stable PDs. The surface modulation for CQDs not only passivates defectsby inhibiting vacancies, but also enhances hole transport capacity by modulatingenergy level mismatch. As a result, the assembled CsPbBr_2I PDs showa responsivity of 0.375 A W~(?1), a detectivity of 1.12 × 10~(13) Jones and an on/off ratio of 10~4. More importantly, the CsPbBr_2I PDs exhibit excellent longtermstability for 12 weeks and can withstand 1000 bending cycles. This workprovides a guideline for the development of perovskite in wireless opticalcommunication.