Chiral Quasi‐2D Hybrid Perovskite p–n Junction Arrays for High‐Performance Self‐Powered Visible‐Band Circularly Polarized Light Detection

ABSTRACT Highly sensitive circularly polarized light (CPL) detectors are essential for optical communication and sensing. Nevertheless, while certain CPL detectors employing single‐component and polycrystalline perovskite active layers are capable of broad‐spectrum detection range, the majority of such devices still suffer from substantial carrier recombination, leading to high energy consumption. The rational design of high‐quality p–n junctions provide a promising strategy for achieving efficient carrier separation and self‐powered operation. Here, we present a high‐performance, self‐powered CPL detector based on quasi‐two‐dimensional (quasi‐2D) chiral hybrid perovskite (CHP) p–n junction microwire (MW) arrays constructed from [(R)/(S)‐β‐MPA] 2 (MA) n‐1 Pb n Br 3n+1 and [(R)/(S)‐β‐MPA] 2 (MA) n‐1 Pb n Br 3n+1‐x I x (MPA = methylphenylethylamine, MA = methylammonium). The built‐in electric field of the p–n junction, the chiral‐induced spin selectivity (CISS) effect of the CHPs, and the high crystallinity with ordered crystallographic alignment of the arrays collectively enable high‐performance self‐powered CPL detection. The device exhibits excellent CPL sensitivity across a broad spectral range of 405–556 nm, with a maximum photoresponsivity ( R max ) of 37.7 A W −1 under 510 nm illumination, an anisotropy factor ( g Iph ) of 0.37, and a high photocurrent on/off ratio (I on / I off ) of 1.29 × 10 4 under 0 V bias. These superior performances highlight the device's great potential for polarization‐based optical communication and encryption applications.