Self‐Powered X‐ray Detector With High Sensitivity and Low Detection Limit Based on Engineered 2D Polar Metal Halide Perovskites

ABSTRACT 2D organic‐inorganic hybrid perovskites (OIHPs) have become an important class of materials for X‐ray detection owing to their diverse structures and unique semiconducting properties. However, despite the progress made so far, the synthesis of high‐quality 2D OIHP single crystals for self‐powered X‐ray detection remains a huge challenge. Here, we constructed the centimeter‐scaled polar OIHP crystals (4‐FBA) 2 (DMA)Pb 2 Br 7 ( 1 , 4‐FBA = 4‐fluorobenzylamine, DMA = dimethylamine). Specifically, 1 possesses large resistivity (3.0 × 10 11 Ω cm), high carrier mobility‐lifetime product (1.5 × 10 3 cm −2 V −1 ) and prominent spontaneous polarization (0.13/2.16 µC cm −2 ), which enable it to perform self‐powered X‐ray detection. A planar Au electrode detector was fabricated on the surface of crystal 1 by sputtering. The detector exhibits excellent self‐powered X‐ray detection performance, featuring high sensitivity (306 µC Gy air −1 cm −2 ) and outstanding radiation stability. Moreover, it maintains good responsivity even under an X‐ray dose rate as low as 118 nGy air s −1 , fully demonstrating its superior overall detection capability. This work sheds light on the design of X‐ray detectors and provides insights for future research on high‐performance X‐ray detection.