Flexible all-inorganic photoconductor detectors based on perovskite/hole-conducting layer heterostructures

The past few years have witnessed the rapid development of all-inorganic metal halide perovskites in optoelectronics. However, the solution-processed perovskite nanocrystal film suffers from low carrier extraction and transport efficiencies because of a large number of grain boundaries. Here, we demonstrate that an enhanced photoresponse is obtained by constructing a perovskite/hole-conducting layer heterostructure photoconductor, resulting from the interfacial charge transfer from perovskite to conducting layer. Furthermore, we develop a trap-assisted charge transfer mechanism to explain the larger photocurrent of the CuSCN heterostructure photoconductor than that of the NiO heterostructure. A saturated photocurrent of 40 μA and a responsivity of 11 A W^-1 at 1 V are obtained for the flexible CsPbBr₃ nanosheet/CuSCN heterostructure. Excellent folding stability and long-term air-stability highlight the promising flexible photodetector applications.