Perovskitizer Tuning Pb <sup>2+</sup> 6s <sup>2</sup> Lone Pair Effects in Hybrid Perovskite Halide Enables Multiaxial Self‐Powered X‐Ray Detection
Ruiqing Li, Bohui Xu, Jianbo Wu, Shihai You, Chengshu Zhang, Chengmin Ji, Zheshuai Lin, Junhua Luo
Abstract
Abstract The stereochemical expression of the n s 2 lone pair significantly impacts symmetry breaking and corresponding photoelectric properties. However, hindered by the symmetric octahedral configuration, the Pb 2+ 6s 2 lone pair in the well‐conductive lead halide hybrid perovskites (LHHP) are normally stereo‐inactive, new approaches to activate the 6s 2 lone pair are still greatly desired. Herein, by exploiting a perovskitizer tuning Pb 2+ lone pair method, the study successfully obtains a stereo‐active 6s 2 in the polar perovskite PA 2 MHy 2 Pb 3 Br 10 (PMPB, PA = n‐propylamine, MHy = methylhydrazine), and unprecedentedly performs a multiaxial self‐powered X‐ray detection. In detail, the stereo‐active 6s 2 lone pair is caused by the coordination bond between the perovskitizer MHy and Pb atom. Emphatically, the N‐Pb bond induces a large angular distortion parameter (≈45 times larger than other LHHP) and the lowest‐symmetric space group ( P 1) crystallization. Therefore, PMPB natively contains multiaxial polarization, which acts as the driving force to separate and transport the X‐ray‐generated carriers, thus enabling multiaxial self‐powered X‐ray detection with a low detection limit (129 nGy s −1 ). This work reveals the relationship between stereo‐active lone pair and polarization and sheds light on future X‐ray detection.