Metal‐Free Perovskites for X‐Ray Detection and Imaging: Progress and Prospects

X‐ray detection is essential in a wide range of fields, including medical diagnostics, industrial nondestructive testing, and homeland security. Among the materials used for X‐ray detection, metal‐free perovskites (MFPs) have recently emerged as promising class materials. They not only retain the excellent optoelectronic properties of conventional perovskites but also offer advantages typical of organic materials, such as flexibility, light weight, and chemical diversity. Importantly, MFPs are nontoxic and water degradable, with a density similar to that of human tissues, making them effective tissue‐equivalent materials. Owing to these unique attributes, MFPs have garnered attention for their potential in low‐cost, environmentally friendly X‐ray detection technologies. In this review, we provide a comprehensive overview of MFPs, focusing on their crystal structures, compositional design, and physical characteristics. We then highlight recent advancements in their application as X‐ray detectors, emphasizing material optimization, device performance, and practical implementation. Finally, we discuss the current challenges in this field and offer perspectives on future directions for MFPs as competitive materials for X‐ray detection.