Self‐Powered Circularly Polarized Photodetectors Based on Chiral (R/S‐MBA) ₂ PbI ₄ Perovskite

Abstract Circularly polarized light (CPL) detection has extensive applications in the fields of optoelectronic devices, information security, biomedical imaging, and so on. Due to their unique structure, the (R)‐(+)‐α‐methylbenzylamine (R‐MBA) and (S)‐(−)‐α‐methylbenzylamine (S‐MBA) are chosen as a chiral cationic template. The chiral 2D perovskite (R/S‐MBA) ₂ PbI ₄ single crystals exhibit high absorption and prominent circular dichroism (CD) signals, highlighting their significant potential for CPL detectors. In this study, a self‐powered (R/S‐MBA) ₂ PbI ₄ circularly polarized photodetector is reported. The responsivity (R), specific detectivity (D ^* ), and light on/off ratio of the (R‐MBA) ₂ PbI ₄ device under 532 nm right‐handed circularly polarized (RCP) light at 0 V bias voltage are 58 mA W ⁻¹ , 2.96 × 10 ¹¹ Jones, and 568. These values of the (S‐MBA) ₂ PbI ₄ device are 61 mA W ⁻¹ , 3.09 × 10 ¹¹ Jones, and 478 under left‐handed circularly polarized (LCP) light at 0 V bias voltage. The photocurrent anisotropy factor (g _Iph ) for (R‐MBA) ₂ PbI ₄ and (S‐MBA) ₂ PbI ₄ is exhibited to be 0.03 and 0.05, demonstrating a strong selectivity for CPL. The biomimetic CPL imaging system, bio‐inspired by mantis shrimp vision, further provides its practical potential in high‐resolution polarization‐sensitive applications. The research offers a solution for next‐generation CPL detection technologies.