An In Situ-Fabricated All-Inorganic Perovskite/MoO3 Heterojunction by Chemical Vapor Deposition and Its Photoresponse Properties

All-inorganic lead halide perovskite CsPbBr 3 has received a lot of attention in the field of optoelectronic devices due to its high absorption coefficient and photoelectric conversion efficiency. Using a heterojunction as the core of a photodetector (PD) to transform the optical signal into an electrical signal compensates for the deficiencies of using a single material. Here, a simple and efficient chemical vapor deposition (CVD) method is used to fabricate a CsPbBr 3 /MoO 3 /ITO heterojunction PD with superior photoresponse properties, including photoresponsivity of 37.209 A W −1 and detectivity of 1.64 × 10 12 Jones at bias voltage of 3 V. Compared with pure CsPbBr 3 perovskite, the responsivity of the PD is 3.54 times as great. As a photosensitive layer, CsPbBr 3 absorbs photons and releases electrons due to its high optical absorption coefficient. The introduction of MoO 3 plays a role in promoting the separation and transport of photogenerated carriers of the heterojunction structure and improves device performance. This study provides groundwork facilitating the use of CVD for in situ growth of high-performance all-inorganic perovskite heterostructures to realize the prospect of large-scale production of perovskite PDs.