Recent advances on two-dimensional metal halide perovskite x-ray detectors

In recent years, two-dimensional metal halide perovskites (MHPs) have attracted increased attention for radiation detection and imaging. Their detection efficiencies are almost comparable to three-dimensional (3D) perovskites. Meanwhile, they demonstrate superior stability to 3D perovskites. The pursuit of high-quality, phase-pure and lead-free two-dimensional MHP materials and large-area fabrication capability for x-ray detectors are among the research hotspots. In this review, we first give a brief introduction of the crystallographic structure, optoelectronic characteristics and preparation methods of high-quality two-dimensional perovskites. In addition, we overview the general working principles of direct and indirect x-ray detection processes and the corresponding performance metrics from the perspective of detection and imaging. Furthermore, we provide a comprehensive discussion on the recent advances in 2D perovskite x-ray detectors and imaging devices. Finally, we pinpoint several major obstacles of 2D x-ray detectors that should be overcome in the near future.