Here we report on the development of non-hygroscopic and lead-free perovskite Cs3Cu2I5 (CCI) scintillator thin films for high-resolution x-ray imaging. The investigation is motivated by the bulk CCI crystal (density of 4.53 g/cm3), which has been reported to exhibit an ultrahigh light yield of 98,000 photons/MeV with reduced afterglow. Thin films were fabricated using two different techniques: hot-wall evaporation and casting of CCI – polymer composite materials. The films fabricated by both these techniques demonstrated high atmospheric stability. Independent of the fabrication method, the x-ray radioluminescence of undoped CCI films showed a bright blue emission at 450 nm from self-trapped exciton emission, whereas Tl-doped CCI films showed emission at 500 nm. Importantly, upon x-ray irradiation, a 100 μm thick CCI film exhibited a relatively high light output of 140% of Kodak Min-R 2000 film. The modulation transfer function (MTF(f)) was approximately 5 lp/mm at 10 % MTF for a 105 μm thick vapor deposited CCI film as well as 800 μm thick CCI – polymer composite film, measured using 70 kVp x-ray images of a tungsten slit phantom. The high air stability, nontoxicity, and high radioluminescence intensity with reduced afterglow, make CCI a potential replacement material for high-resolution, high-speed x-ray imaging.
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