(333d) Self-Powered Circularly Polarized Light Detection Enabled By Chiral Two-Dimensional Perovskites with Mixed Chiral?Achiral Organic Cations

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 remarkable 10-fold increase in circular dichroism signals compared to (R, S-MBA)₂PbI₄ perovskites. Additionally, the (R-MBA_0.5nBA_0.5)₂PbI₄ perovskite films exhibit a preferred crystallographic orientation, facilitating charge carrier transport within the perovskite films. The CPL photodetectors based on the mixed-cation perovskites exhibit self-powered capabilities with an impressive specific detectivity of 2.45 × 10¹² Jones at 0 V bias. Moreover, these devices show a distinguishability (g_res) 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.