Self‐Powered Wide‐Narrow Bandgap‐Laminated Perovskite Photodetector with Bipolar Photoresponse for Secure Optical Communication

BM to the bottom/top electrodes, respectively, resulting in a negative and positive bipolar response. Finally, based on positive NIR signal as the effective signal and negative visible signal as the interference signal, the SOC system is realized, where the positive NIR signal is well hidden by the negative visible signal. This work provides a simple and feasible strategy for fabrication of laminated perovskite films to achieve bipolar response.