Zhi-Xiang Zhang, Long-Hui Zeng, Xiao-Wei Tong, Yang Gao, Chao Xie,*, Yuen Hong Tsang,Lin-Bao Luo*, Yu-Cheng Wu

Abstract: In this work, we reported on the large-scale synthesis of polycrystalline multilayer PtSe2 film with typical semimetallic characteristics. With the availability of the large-area film, we constructed a heterojunction composed of multilayer PtSe2 and Cs doped FAPbI3, which can function as a self-driven photodetector in a broadband wavelength from the ultraviolet (UV) to NIR region. Further photoresponse analysis revealed that the heterojunction device showed outstanding photosensitive characteristics with a large Ilight/Idark ratio of 5.7×103, high responsivity of 117.7 mAW-1 and decent specific detectivity of 2.91×1012 Jones at zero bias. More importantly, the rise/fall times were estimated to be 78/60 ns, rendering our device the fastest device among perovskite based photodetectors reported so far. In addition, it was also observed that the PtSe2/perovskite photodetector can almost retain its photoresponse properties after storage in ambient condition for 3 weeks. This study suggests the potential of the present PtSe2/perovskite heterojunction for future air-stable ultrafast photodetecting applications.