Self-Powered Circularly Polarized Light Detection Enabled by Chiral Two-Dimensional Perovskites with Mixed...

Direct detection of circularly polarized light (CPL) holds great promise for the development of various optical technologies. Chiral 2D organic-inorganic halide perovskites make it possible to fabricate CPL-sensitive photodetectors. However, selectively detecting left-handed circularly polarized (LCP) and right-handed circularly polarized (RCP) light remains a significant challenge. Herein, we demonstrate a greatly enhanced distinguishability of photodiode-type CPL photodetectors based on chiral 2D perovskites with mixed chiral aryl (R)-(+),(S)-(-)-α-methylbenzylammonium (R,S-MBA) and achiral alkyl n-butylammonium (nBA) cations. The (R,S-MBA_0.5nBA_0.5)₂PbI₄ perovskites exhibit a 10-fold increase in circular dichroism signals compared to (R,S-MBA)₂PbI₄ perovskites. The CPL photodetectors based on the mixed-cation perovskites exhibit self-powered capabilities with a specific detectivity of 2.45 × 10¹² Jones at a 0 V bias. Notably, these devices show high distinguishability (g_res) factors of -0.58 and +0.54 based on (R,S-MBA_0.5nBA_0.5)₂PbI₄ perovskites, respectively, surpassing the performance of (R-MBA)₂PbI₄-based devices by over 3-fold and setting a record for CPL detectors based on chiral 2D n = 1 perovskites.