Bromine Doping of MAPbI 3 Films Deposited via Chemical Vapor Deposition Enables Efficient and Photo‐Stable Self‐Powered Photodetectors

Hybrid lead‐halide perovskite photodetectors represent a highly promising technology, but long‐term operational stability under ambient conditions must be improved before these devices can be deployed in real‐world applications. In consideration of the relationship between film quality and device stability, this work explored photodetectors based on bromine‐doped CH 3 NH 3 PbI 3 (i.e., CH 3 NH 3 PbI 3− x Br x , MAPbI 3− x Br x in short form) perovskite layers deposited via chemical vapor deposition (CVD). These layers have good compactness and no pinholes, hence they enable sandwich‐type photodetectors with high performance in self‐powered mode. Under 632 nm illumination, these photodetectors achieve a level of responsivity as high as 45 A/W, along with a specific detectivity of 1.15 × 10 14 Jones and an external quantum efficiency of 8.84 × 10 3 %. It is important to note that these photodetectors exhibit outstanding operational stability that is superior to that of their pure‐iodide (i.e., CH 3 NH 3 PbI 3 , MAPbI 3 in short form) counterparts. When the MAPbI 3− x Br x devices are stressed under simulated solar illumination in ambient air, their photoresponse is maintained to within 29% loss of the original value for more than 500 h, while the photoresponse of the MAPbI 3 devices is reduced by 62%. The key figures of merit of the fabricated devices and their operational level of photostability are expected to create new avenues for future outdoor photodetector applications.