High-Performance Self-Powered Photodetectors with Space-Confined Hybrid Lead Halide Perovskite Nanocrystals

摘要

Hybrid lead halide perovskites are widely studied in photodetectors due totheir excellent optoelectronic properties. However, most of the perovskitephotodetectors require an external power source, which adds additional costsand limits their application. Here, a self-powered photodetector based onthe heterojunction formed by methylammonium lead tribromide perovskitenanocrystals (MAPbBr_3 NCs) and mesoporous TiO_2 (m-TiO_2) is demonstratedby a space-confined growth method. The NCs are uniformly grownon the m-TiO_2 framework and mirco-heterojunctions are formed. Systematicresearch shows that the built-in electric field of the mirco-heterojunctionsincreases the exciton dissociation and carrier transport. In the absence of anexternal power supply, the photodetectors display an impressive on/off ratio(>10~5) and high detectivity (>10~(11) Jones) under 100 mW cm~(?2) solar irradiation.In addition, the winning device shows excellent long-term stability (photocurrentmaintains over 92 after exposure of 102 days to the air), benefitingfrom the enhanced binding energy and reduced defect density of NCs. It isbelieved that this study sheds light on the further development of self-poweredperovskite-based photodetectors with high performance.