A-site Cation Exchange Enables a High-performance CsPbBr3 Photodetector for Laser Eavesdropping Systems

Owing to the absence of organic cations, all-inorganic perovskite exhibits superior thermal and irradiation stability compared to organic-inorganic perovskite. However, it is difficult for the traditional solution method to produce pinhole-free and phase-pure all-inorganic perovskite films, which hinders its application. Here, a method of in situ A-site cation exchange to synthesize CsPbBr3 films is introduced. The MAPbBr(3) films are treated with CsAc solution to initiate cation exchange, where the intermediate product MAAc plays a crucial role in guiding grain growth during evaporation, resulting in the production of pinhole-free and phase-pure CsPbBr3 films. The self-powered photodetector, based on compact and pinhole-free CsPbBr3 film, exhibits excellent performance with an LDR of 126.7 dB, a detectivity of 1.1 x 10(13) Jones, and a rise/decay time of 2.9/25.1 mu s. Furthermore, the photodetector maintains over 90% of its original performance after a 2500 s irradiation test and a 30-day air exposure test. Benefiting from the exceptional device performance and stability, the photodetector proves to be a valuable component in the laser eavesdropping system.