Nanoscale scintillating materials for X-ray imaging: fundamentals and applications

X-ray imaging based on scintillators holds significant importance in medical diagnosis, security inspection, and industrial production. Nanoscale scintillators (NSs) with lower processing costs and synthesis temperatures possess the advantages of easy shape customization and flexibility in imaging, thus making them a viable solution to address the various limitations of traditional single-crystal scintillators. Here, this review summarizes the research progress of NSs in the field of X-ray indirect imaging from the perspectives of fundamentals, materials, structure engineering and applications. Initially, the scintillation mechanism and performance requirements of NSs are outlined with a detailed classification of emission modes for each type of NS. Subsequently, nanoscale scintillating materials, including II–VI quantum dots, metal halides, rare earth ion-doped compounds, metal clusters and metal–organic frameworks, are discussed with emphasis on enriching the material inventories and modulating the scintillation properties. Furthermore, the structural forms of NSs in scintillation screens and their research progress in multi-mode X-ray imaging applications are presented. Finally, the main challenges for practical applications and future research directions are discussed. This review suggests that the exploration of NSs could facilitate significant breakthroughs in X-ray imaging in terms of imaging performance and application scenarios in the future.