Liquid-Phase Epitaxial Growth of Large-Area MAPbBr3-,,Cl,,/CsPbBr3 Perovskite Single-Crystal Heterojunction for Enhancing Sensitivity and Stability of X-ray Detector

Metal halide perovskites have emerged as next generation semiconductors for X-ray detection because of their excellent photoelectric properties. However, severe ion migration in three-dimensional (3D) halide perovskites usually causes dark current drift in radiation detectors, especially in high electric fields. Here, we report a liquid-phase epitaxial method based on inverse temperature crystallization (ITC), with which a hybrid/allinorganic 3D perovskite single-crystal heterojunction is constructed, using an orientated CsPbBr3 single crystal as a substrate. MAPbBr3-nCln/CsPbBr3 single-crystal heterojunctions and single crystal arrays (through the addition of a mask onto the substrate) with good lattice matching were successfully constructed, laying the foundation for high-performance X-ray detectors. In particular, the MAPbBr3/CsPbBr3 heterojunction drastically enhances the X-ray response of the CsPbBr3 single crystal, with a record-high sensitivity of 2.0 x 105 mu C Gyair -1 cm-2 and lowest detection limit of 96 nGyair s-1 for 120 keV hard X-ray detection. Moreover, the dark current drift caused by ion migration is suppressed to 3.92 x 10-4 nA cm-1 s-1 V-1 even in a high reverse electric field of -125 V mm-1. Based on the superior detection performance, it is confirmed that a robust and uniform X-ray imaging detector with good resolution was successfully devised using the heterojunction. Our study provides a simple strategy for constructing perovskite single-crystal heterojunction films and arrays that effectively suppress ion migration that otherwise occurs in 3D halide perovskite single crystals to enable the creation of robust ultrasensitive Xray detection and imaging systems.

Automated summary

This study presents a liquid-phase epitaxial method to construct perovskite single-crystal heterojunctions, effectively suppressing ion migration in three-dimensional halide perovskites and enabling the creation of high-performance X-ray detectors. The constructed MAPbBr3/CsPbBr3 heterojunction exhibits a record-high sensitivity and a low detection limit, while suppressing dark current drift even in a high reverse electric field.