PA2PbBr4/MAPbBr3 Heterojunction X‐Ray Detector with Enhanced Sensitivity and Excellent Self‐Powered Functionality

Abstract Heterojunctions combining 2D and 3D perovskites have caused a surge in the research on X‐ray detectors. The enhanced charge transport facilitated by the built‐in electric field further amplifies the potential of this material system, paving the way for highly sensitive and efficient X‐ray detectors. In this study, PA 2 PbBr 4 single‐crystal film with a thickness of 10 µm is successfully grown on the surface of MAPbBr 3 substrate via liquid phase epitaxial method, forming a 2D/3D heterojunction. This innovative detector exhibits a dramatically enhanced sensitivity of 3.81 × 10 4 µC Gy −1 cm −2 at an X‐ray tube voltage of 70 keV and a bias of 50 V mm −1 , along with an ultra‐low detection limit of 11.84 nGy s −1 , surpassing the performance of the conventional MAPbBr 3 X‐ray detectors by a factor of four and 2 × 10 3 times higher than that of commercialized α ‐Se detectors. Furthermore, the 2D/3D heterojunction exhibits exceptional self‐powered X‐ray detection capabilities, achieving a remarkable sensitivity of 3562.26 µC Gy −1 cm −2 at 70 keV X‐ray tube voltage. This superior performance implies reduced energy consumption, high portability, decreased ion migration, and provides inspiration for the next generation of high‐performance X‐ray detectors.