Preparing the In-doped lead-free Cs3Cu2I5 perovskite scintillator by a co-firing technique for its application in high-resolution X-ray imaging

The perovskite scintillators have been extensively studied recently for their merits of tunable emission spectra and simple preparation processes. However, the practical applications of perovskite scintillator-based X-ray image sensor are still impeded by inadequate radioluminescence, poor environmental stability, and low imaging resolution. Herein, we demonstrate a scalable co-firing method to fabricate high-quality lead-free Cs 3 Cu 2 I 5 perovskite scintillator and an Indium (In)-doping strategy is introduced to enhance its radioluminescence performance at the same time. The In-doped Cs 3 Cu 2 I 5 obtains a high PLQY of 77.9% and a relative light output of 53372   ph/MeV, which are 0.34 and 1.08 times higher than those of the undoped counterpart, respectively. The X-ray detection limit of the In:Cs 3 Cu 2 I 5 can reach 150.55 nGy air /s, 36.53 times lower than the requirement for X-ray medical diagnosis. The synthesized scintillator also shows superior stability under continuous high dose X-ray irradiation of 6800 μGy air /s for 120   minutes, maintaining 95% of its initial radioluminescence intensity. Furthermore, a large-area (300 cm 2 ) flexible perovskite scintillator film is prepared, which owns a much competitive resolution of 10 lp/mm and less distortion in X-ray imaging. This work provides a practical path for the wide application of perovskite scintillator in the field of X-ray detection and imaging in near future.