Perovskite scintillators have been widely used in X-ray detection; however, lead-based perovskite scintillators with strong self-absorption reduce the optical-coupling efficiency, significantly resulting in a relatively low optical yield. Herein, we prepared self-trapped exciton-emitting lead-free perovskite nanoparticles (Cs3Cu2I5) using a green antisolvent method and fabricated large-scale (Ø = 10 cm) scintillation screens by uniformly dispersing them in a transparent styrene monomer. The antisolvent optimized the crystallization of Cs3Cu2I5, achieving a photoluminescence quantum yield of 87.2%. The scintillation screen prepared in the liquid phase significantly improves the luminous uniformity and led to a high spatial resolution of 7.3 lp/mm. It exhibits an excellent linear response to X-ray dose rate and a low detection limit of 63 nGyair/s. Besides, the transparent matrix enhances the stability of Cs3Cu2I5 with remarkable radiation-resistant hardness even under continuous X-ray irradiation for 120 min.

X‐ray photography plays an important role in the fields of medical treatment, security inspection, and non‐destructive testing. The high image quality depends on X‐ray detectors with excellent properties. To meet the future demand for high‐performance scintillation screens, adding a new luminescent center in Cs3Cu2I5 by doping is considered. The successful incorporation of Mn brought a new luminescence peak at 565 nm. Different excitation modalities such as ultraviolet and X‐rays have the ability to tune luminescence. X‐ray can promote the energy transfer efficiency of self‐trapped excitons and non‐radiative intermediate trap states to doping Mn2+ ions. This results in a higher radioluminescence intensity of a radioluminescence light yield of 65 000 Photons MeV−1. Subsequently, a Cs3Cu2I5: Mn scintillation screen is prepared by anodized aluminum oxide (AAO) template. The array channel structure of the AAO template strongly suppresses the internal scintillation light scattering, allowing more scintillation photons to be emitted efficiently. Under the combined effect of Mn‐enhanced radioluminescence properties and AAO template suppressed light scattering, it obtains the lowest detection limit of 49 nGyair s−1. High X‐ray imaging quality has been achieved for circuit boards, beetles, and ball‐point pens and reached a high X‐ray imaging resolution of 11.8 lp mm−1.

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