Enhanced Performance of All‐Inorganic Lead Halide Perovskite/MoS2 Heterojunction Photodetectors by Achieving Interfacial Carrier Separation

A heterojunction interface engineering aimed at improving the performance of all‐inorganic lead halide perovskite photodetectors (PDs) is demonstrated by coupling the two‐dimensional (2D) MoS 2 materials with CsPbBr 3 used in the chemical vapor deposition method in situ‐grown. The MoS 2 carrier extraction layer facilitates electron injection, while the large injection barrier of the CsPbBr 3 /MoS 2 heterojunction depletion layer keeps holes in the perovskite layer, resulting in effective separation of photogenerated carriers at the heterojunction interface. Moreover, the photoluminescence quenching and lifetime shortening of the heterojunction further prove that there is a large amount of charge transfer between the CsPbBr 3 and MoS 2 interface. As a result, PDs based on the CsPbBr 3 /MoS 2 /interdigitated array electrodes (IDA) heterojunction exhibit remarkable performance, such as high photoresponsivity (23.4 A W −1 ), detectivity (1.48 × 10 13 Jones), and switching ratio (1.35 × 10 5 ), all of which are an order of magnitude better than pure CsPbBr 3 PDs. The heterojunction PD also presents a superior response time (0.07 ms).