Efficient Cs₃Cu₂I₅ X-ray Scintillators by Mass-Production-Applicable Fast-Closed-Space-Evaporation

Advancing X-ray imaging systems necessitate scintillators that deliver both high sensitivity and high spatial resolution, a long-standing challenge due to material and fabrication limitations. Low-dimensional metal halides such as Cs3Cu2I5 are intrinsically promising for this application, yet scalable synthesis of thick, high-quality films remains a significant bottleneck. We introduce a rapid (∼minutes) and highly efficient closed-space evaporation (CSE) method for growing phase-pure Cs3Cu2I5 films up to and exceeding 100 μm in thickness. These films function as high-performance scintillators, exhibiting a remarkable light yield of 55,000 photons/MeV, enabling X-ray detection at an exceptionally low dose rate of 0.21 nGyair/s, and achieving a spatial resolution of up to 23 lp/mm. Furthermore, they demonstrate outstanding radiation hardness, maintaining stable characteristics after an exposure equivalent to more than 3,000 clinical chest image X-ray exposures. This CSE technique represents a transformative approach to fabricating high-quality metal halide scintillators, opening avenues for the development of cost-effective, ultrasensitive, and high-resolution X-ray imaging modalities.