Interlayer Polymerization of 2D Chiral Perovskite Single‐Crystal Films toward High‐Performance Flexible Circularly Polarized Light Detection

RESEARCH ARTICLE www.afm-journal.de Interlayer Polymerization of 2D Chiral Perovskite Single-Crystal Films toward High-Performance Flexible Circularly Polarized Light Detection Yingjie Zhao, Xing Yin, Zhenkun Gu, Meng Yuan, Jianpeng Ma, Tenglong Li, Lei Jiang, Yuchen Wu,* and Yanlin Song* 2D chiral perovskite has greatly boosted the development of optoelectronic devices, ranging from nonlinear optics, spintronics, and ferroelectrics to energy harvesting devices. Despite circularly polarized light (CPL) detection based on chiral perovskite has been achieved, the environmental humidity-, ultraviolet (UV), and temperature-induced structural degradation and its large electro-phonon coupling restrict its commercial application. Here, this study first realizes polymerized chiral perovskite single-crystal films by combining in situ cross-linking polymerization with the space-confined crystallization method. Compared with uncross-linked chiral perovskites, cross-linked chiral perovskites exhibit enhanced crystallinity and lattice rigidity, yielding high-performance circularly polarized photodetectors with a maximum anisotropy factor of 0.22, the responsivity of 1.6 A W−1, and detectivity of 2.17 × 1013 Jones. In addition, flexible circularly polarized photodetectors with extremely high mechanical stability are also realized originating from the polymer-like behavior of cross-linked chiral perovskite single-crystal films. This study opens up new avenues to further enhance the performance and stability of portable and wearable devices based on chiral perovskites. 1. Introduction Polarized light detection, especially circularly polarized light (CPL) detection, has tremendously accelerated the application Y. Zhao, X. Yin, Z. Gu College of Chemistry Zhengzhou University Zhengzhou 450001, P. R. China M. Yuan, J. Ma, T. Li, L. Jiang, Y. Wu Key Laboratory of Bio-inspired Materials and Interfacial Science Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190, P. R. China E-mail: wuyuchen@iccas.ac.cn Y.Song Key Laboratory of Green Printing Instituteof Chemistry ChineseAcademy of Sciences Beijing 100190,P.R.China E-mail: ylsong@iccas.ac.cn The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.202306199 DOI: 10.1002/adfm.202306199 of various optoelectronic devices, ranging from classical ellipsometry, spectroscopy, and imaging to quantum computation and communication.[1–5] So far, the realization of CPL detection mainly relies on bulk opti- cal wave plates and artificial photonic struc- tures accompanied by large footprints and high costs, thus hindering the miniaturiza- tion and commercialization applications of devices.[6,7] To simplify the structure of the device and realize the on-chip integration of circularly polarized photodetectors, ma- terials with intrinsic chirality are widely ex- plored, such as organic small molecules, quantum dots, and polymers, but their rel- atively weak response to CPL restricts their practical applications.[8–14] Two-dimensional (2D) chiral per- ovskites, a category of diversified opto- electronic materials, have gained much attention in recent years due to sym- metry breaking of structure,[15–18] spin polarization,[19,20] Rashba–Dresselhaus spin-orbit coupling,[21] and low-cost solution processing,[15,16] thus leading to great achievements in the fields of ferroelectrics,[22,23] spintronics,[19,20] and nonlinear optics.[24,25] Due to its structural diversity and large anisotropic absorption for circularly polarized light, CPL photodetectors have been fabricated based on chiral perovskites.[2,26–37] Compared with three-dimensional organic–inorganic hybrid perovskites, the moisture stability of 2D perovskite is enhanced due to the hydrophobicity of the large intercalating ammoniums.[38–42] However, poor temperature, ultraviolet (UV) stability, and large electro-phonon coupling still hamper the efficiency im- provement and bottle