Boosting Two-Dimensional MoS₂/CsPbBr₃ Photodetectors via Enhanced Light Absorbance and Interfacial Carrier Separation

Transition metal dichalcogenides (TMDs) are promising candidates for flexible optoelectronic devices because of their special structures and excellent properties, but the low optical absorption of the ultrathin layers greatly limits the generation of photocarriers and restricts the performance. Here, we integrate all-inorganic perovskite CsPbBr₃ nanosheets with MoS₂ atomic layers and take the advantage of the large absorption coefficient and high quantum efficiency of the perovskites, to achieve excellent performance of the TMD-based photodetectors. Significantly, the interfacial charge transfer from the CsPbBr₃ to the MoS₂ layer has been evidenced by the observed photoluminescence quenching and shortened decay time of the hybrid MoS₂/CsPbBr₃. Resultantly, such a hybrid MoS₂/CsPbBr₃ photodetector exhibits a high photoresponsivity of 4.4 A/W, an external quantum efficiency of 302%, and a detectivity of 2.5 × 10¹⁰ Jones because of the high efficient photoexcited carrier separation at the interface of MoS₂ and CsPbBr₃. The photoresponsivity of this hybrid device presents an improvement of 3 orders of magnitude compared with that of a MoS₂ device without CsPbBr₃. The response time of the device is also shortened from 65.2 to 0.72 ms after coupling with MoS₂ layers. The combination of the all-inorganic perovskite layer with high photon absorption and the carrier transport TMD layer may pave the way for novel high-performance optoelectronic devices.