Polar 3D Perovskitiod Constructed by Asymmetric Diamine for Stable Self‐Driven X‐Ray Detection

Abstract Polar 3D organic–inorganic hybrid perovskites (OIHPs) with the bulk photovoltaic effect (BPVE) have important application value in self‐driven X‐ray detection, due to their excellent semiconductor properties. However, A‐site cations are limited by the tolerance factor, making it difficult to construct ABX 3 ‐type polar 3D perovskites. Therefore, it is necessary to explore polar 3D perovskitiods with excellent semiconductor properties for self‐driven X‐ray detection. Herein, by introducing an asymmetric diamine 3‐methylaminopropylamine (3‐MAPA) cation, a polar 3D perovskitiod, (3‐MAPA)Pb 2 Br 6 ( 1 ) is successfully constructed. Specifically, the dipole‐oriented arrangement and intrinsic polarity of 3‐MAPA cations endow a non‐centrosymmetric structure of 1 single crystal (SC). Notably, under X‐ray irradiation, the polar 1 SC exhibits a remarkable bulk photovoltaic of 0.8 V, which is beneficial for self‐driven X‐ray detection. Consequently, the 1 ‐based detector shows a sensitivity of 101 µC Gy −1 s −1 and a low detection limit of 189 nGy s −1 at 0 V bias. Meanwhile, 1 SC‐based X‐ray detector exhibits less ion migration due to the abundant N─H···Br hydrogen bonding interaction within the structure, leading to a smaller dark current drift, which supports stable X‐ray detection. This study attains stable self‐driven X‐ray detection based on polar 3D perovskitiods, which enriches the candidates for self‐driven X‐ray detectors.