High-performance perovskite photodetectors based on CH₃NH₃PbBr₃ quantum dot/TiO₂ heterojunction

Organo-lead halide perovskite materials have opened up a great opportunity to develop high performance photodetectors because of their superior optoelectronic properties. The main issue with perovskite-only photodetector is severe carrier recombination. Integration of perovskite with high-conductive materials such as graphene or transition metal sulfides certainly improved the photoresponsivity. However, achieving high overall performance remains a challenge. Here, an improved photodetector is constructed by perovskite quantum dots (QDs) and atomic layer deposited ultrathin TiO₂ films. The designed CH₃NH₃PbBr₃ QD/TiO₂ bilayer device displays inclusive performance with on/off ratio of 6.3 × 10², responsivity of 85 A W^-1, and rise/decay time of 0.09/0.11 s. Furthermore, we demonstrate that interface plays a crucial role in determining the device current and enhance the overall performance of heterostructure photodetector through interface engineering. We believe that this work can provide a strategy to accelerate development of high-performance solution-processed perovskite photodetectors.