Two-dimensional (2D) metal halide perovskites have great potential for applications in photodetectors (PDs), but there are still many challenges in the simple and efficient construction of their heterojunctions and the realization of excellent self-powered functions. In this work, we employ a simple ion exchange strategy to directly grow a 2D PEA2PbI4 layer on the PEA2PbBr4 film using a simple and easily implemented solution method. By precisely controlling the concentration of the phenethylamine hydroiodide/isopropanol (PEAI/IPA) solution, high-quality PEA2PbBr4/PEA2PbI4 heterojunction films are obtained. Furthermore, the self-powered PDs assembled based on the 2D/2D PEA2PbBr4/PEA2PbI4 heterojunction exhibit outstanding self-powered photoelectric performance across the UV-visible spectrum, with a responsivity of 75.6 mA/W and a detectivity of 4.16 × 1011 Jones, respectively, which are more than five times that of the PEA2PbBr4 photodetector. In particular, this heterojunction photodetector exhibits excellent long-term self-powered photoelectric switching characteristics and environmental stability.
Luo et al. (Fri,) studied this question.