Ferro‐Pyro‐Phototronic Effect‐Based Ferroelectric 2D Perovskite Single Crystals for Self‐Powered Photodetection With Dynamically Tunable Polarization Ratio

ABSTRACT Polarimetric photodetection serves as a foundational technology for polarization imaging, sensing, lidar, and optical communication. Two‐dimensional (2D) metal halide perovskites demonstrate remarkable polarization‐sensitive characteristics due to their distinctive parallel layered crystal structure. Nevertheless, the ability to dynamically modulate the polarization ratio in current polarization detectors remains constrained. Furthermore, the majority of these detectors depend on polycrystalline thin films to adjust the polarization ratio, a method that is detrimental to efficient carrier transport and significantly limits their practical applications in polarized optical communication. In response to these challenges, this study introduces the intrinsic pyroelectric effect of 2D ferroelectric perovskite single crystals. By exploiting the synergistic interaction between ferroelectric polarization and single‐crystal anisotropy, we successfully fabricate polarimetric photodetectors with high responsivity and dynamically tunable polarization ratio. This work provides a strategy for developing high‐performance, dynamically tunable polarimetric photodetectors (PDs) based on ferroelectric single‐crystal platforms for secure optical communication.