Achieving High Loading Capacity of Perovskite Nanocrystals in Pore-Reamed Metal–Organic Frameworks for Bright Scintillators

Abstract

Lead halide perovskite nanocrystal (PNC) scintillators featuring a fast decay and a high radiation hardness have garnered significant attention. A high PNC loading is essential to ensure a strong X-ray absorption for scintillator applications, but concentrated PNCs tend to aggregate in the solid state, resulting in significant emission quenching. Employing a dispersion medium offers a promising strategy to produce high-loading PNC solids without agglomeration. Herein, we synthesize CsPbBr₃ PNC/metal–organic framework (MOF) nanostructures to achieve high-loading PNCs within MOF hosts. The macroporous cavities of hierarchically porous (HP) MOFs can host more PNCs than the confined nanometer-scale spaces of microporous MOFs. Additionally, the surface-rich structure of MOFs aids in dispersing PNCs, effectively reducing aggregation-induced emission quenching. We find that HP-MOFs can achieve a high PNC loading ratio of 75%, as well as the less-aggregated PNCs. As a result, the PNC/HP-MOF scintillator exhibits a 2.3 times higher light yield than that of the PNC scintillator, primarily resulting from the enhanced luminance efficiency of well-dispersed PNCs. The bright and fast features of nanostructure scintillators enable static and dynamic X-ray imaging for industrial inspection applications. These findings highlight that constructing a high-loading nanostructure is crucial for advancing the X-ray imaging applications of PNC scintillators.