Perovskite Nanostructures for X-Ray Imaging Scintillators

The fast rising demand for the ultralow detection limit of ionizing radiation in medical radiography, high-energy physics and security screening, has led to extensive research on X-ray imaging scintillators and detections. However, high-performance scintillators consist mainly of ceramic that needs harsh and costly preparation conditions. Therefore, searching for new scintillation materials is of great interest to material scientists, chemists, and engineers. Organic emitters and perovskites, are excellent candidates as scintillation materials due to their good processability and low-fabrication cost. In this talk, we will present the room-temperature synthesis of a colloidal scintillator comprising CsPbBr3 nanosheets of large concentration (up to 150 mg/mL). We found that the CsPbBr3 colloid exhibits a light yield (∼21000 photons/MeV) higher than that of the commercially available Ce:LuAG single-crystal scintillator (∼18000 photons/MeV). Interestingly, we reveal that the energy transfer process inside those stacked thin and thick nanosheet solids is indeed responsible for their superb scintillation performance. Moreover, we will present a highly efficient energy transfer strategy between the interfaces of these CsPbBr3 perovskite nanosheets and thermally activated delayed fluorescence (TADF) to obtain an efficient and reabsorption-free organic X-ray imaging scintillator with excellent performance. More specifically, the fabricated nanocomposite scintillators exhibit a high X-ray imaging resolution of around 100 μm and a low detection limit of 38.7 nGy/s. This detection limit is about 142 times lower than a typical dose of X-ray medical imaging, making this composite an excellent candidate for X-ray radiography.