Indium-doped perovskite-related cesium copper halide scintillator films for high-performance X-ray imaging

Scintillators are widely utilized in high-energy radiation detection in view of their high light yield and short fluorescence decay time. However, constrained by their current shortcomings, such as complex fabrication procedures, high temperature, and difficulty in the large scale, it is difficult to meet the increasing demand for cost-effective, flexible, and environment-friendly X-ray detection using traditional scintillators. Perovskite-related cesium copper halide scintillators have recently received multitudinous research due to their tunable emission wavelength, high photoluminescence quantum yield (PLQY), and excellent optical properties. Herein, we demonstrated a facile solution-synthesis route for indium-doped all-inorganic cesium copper iodide (Cs3Cu2I5) powders and a high scintillation yield flexible film utilizing indium-doped Cs3Cu2I5 powders. The large area flexible films achieved a PLQY as high as 90.2% by appropriately adjusting the indium doping concentration, much higher than the undoped one (73.9%). Moreover, benefiting from low self-absorption and high PLQY, the Cs3Cu2I5:In films exhibited ultralow detection limit of 56.2 nGy/s, high spatial resolution up to 11.3 lp/mm, and marvelous relative light output with strong stability, facilitating that Cs3Cu2I5:In films are excellent candidates for X-ray medical radiography. Our work provides an effective strategy for developing environment-friendly, low-cost, and efficient scintillator films, showing great potential in the application of high-performance X-ray imaging.