Advancements in Metal Halide Perovskites and their Derivatives for Direct‐Type X‐Ray Detectors

Abstract Metal halide perovskites and their derivatives have emerged as promising candidates for direct‐conversion X‐ray detectors owing to their strong X‐ray attenuation ability, remarkable defect tolerance, large electric resistivity, and cost‐effective solution processability. Existing reviews have predominantly focused on device performance breakthroughs in perovskite X‐ray detectors, yet critical gaps persist in addressing material optimization strategies and structural derivative exploration. This review first summarizes the research progress of the X‐ray detector and the applications of perovskites, as well as their derivatives in detection technologies. Subsequently, it introduces fundamental properties and X‐ray detection performance of halide materials with different crystal structures, including ABX 3 , A 2 BB'X 6 , A 3 B 2 X 9 , Ruddlesden–Popper (R m A n−1 B n X 3n+1 ), and metal‐free perovskites. The performance‐limiting mechanism and corresponding defect‐mediated optimization are further analyzed, establishing a material design framework for developing highly sensitive metal halide perovskite‐based detectors. The last part envisions strategic domains spanning charge transport engineering, biocompatibility and eco‐friendliness considerations, flexible and self‐powered perovskite system design, high‐quality and efficient preparation methods, and high operational stability enhancements, constructing a comprehensive framework for advancing perovskite‐based detection technologies. This review provides insightful inspiration for the development of novel X‐ray detectors.