X-ray luminescent metal–organic frameworks: design strategies and functional applications

X-ray scintillator materials have attracted considerable attention due to their versatile and remarkable properties, leading to advanced applications in materials science, information technology, and biomedicine. In this review, we carefully summarize the latest developments in metal–organic framework (MOF)-based X-ray scintillator materials. First, we discuss the design strategies for MOF-based X-ray scintillators from three perspectives: regulation of the inorganic and organic components, post-synthetic modification of frameworks, and guest-loading within MOF pores. Notably, many of these strategies, which have proven effective in enhancing the performance of other functional MOFs, have yet to be fully utilized to improve MOF-based X-ray scintillators. Second, among the reviewed MOF materials, we categorize them according to the position of the metal ions in the periodic table: fourth-period, fifth-period, and sixth-period metal elements. Within each category, we analyze the progress made with MOFs containing the same metal ion and explore the possible mechanisms behind their performance. Third, we highlight the applications of MOF-based X-ray scintillators in high-sensitivity and high-resolution X-ray detectors, flexible imaging, and X-ray radiation therapy. In this section, we aim to elucidate the relationship between the structural characteristics of MOFs and their practical applications. Finally, based on the achievements discussed, we provide insights into the limitations, major challenges, and future directions in this area, with the hope of inspiring further research on MOF-based X-ray scintillators and their advanced applications. We aspire that this review will encourage innovative research leading to the development of smarter fluorescent materials and devices.