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

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 ABX₃-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)Pb₂Br₆ (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.