Flexible, High Scintillation Yield Cu 3 Cu 2 I 5 Film Made of Ball‐Milled Powder for High Spatial Resolution X‐Ray Imaging

Abstract Cu halide materials with low electronic dimension show great scintillation properties with high photoluminescence quantum yield (PLQY) and large Stokes shift, which can result in reabsorption‐free scintillators. However, there is still a need for a large‐scalable method to fabricate large amount of scintillation powder and large‐size scintillation films. In this regard, a high scintillation yield Cu 3 Cu 2 I 5 −PDMS flexible film utilizing ball‐milled Cu 3 Cu 2 I 5 powder is developed. The ball‐milled Cu 3 Cu 2 I 5 powder shows a high PLQY of 74.5%, narrow emission peak of 80 nm and good ambient stability, demonstrating the potential of ball‐milling method for large‐scale scintillator production. Furthermore, the Cu 3 Cu 2 I 5 −PDMS film shows even high PLQY exceeding 90%, which may be ascribed to the passivation effect of PDMS resulting in a little longer carrier lifetime. The flexible Cu 3 Cu 2 I 5 −PDMS film can further deliver high spatial resolution of 6.8 lp mm −1 @0.2 MTF in X‐ray imaging and good stability under steady X‐ray illumination. This work demonstrates that the ball‐milling method could be an effective approach for large‐scale fabrication of low electronic dimensional scintillation materials.