25.7 lp/mm High‐Resolution X‐Ray Imaging Using Robust Zero‐Dimensional Copper Halide Nanoarray Screens

ABSTRACT High‐resolution scintillation screens with superior light yield play a critical role in many applications. However, conventional single‐crystal scintillators face limitations including challenges in ultra‐thin precision fabrication, hygroscopic nature, and relatively low light yield, which hinder the development and application of high‐resolution X‐ray detectors. In this work, a Cs 3 Cu 2 I 5 ‐AAO scintillation screen is fabricated using a negative‐pressure‐assisted low‐temperature solution synthesis method with an anodic aluminum oxide (AAO) template, which achieves ultra‐bright luminescence with a light yield (LY) >70 000 photons/MeV and high spatial resolution (<20 µm). Notably, in addition to the conventional self‐trapped exciton (STE) emission (λ STE = 450 nm), the scintillator exhibits an unprecedented ultrafast blue emission (λ BL = 438 nm) with an average lifetime of τ avg = 2.279 ns. This phenomenon is reported for the first time in the Cs 3 Cu 2 I 5 system. Based on reasoned speculation, we propose a surface V I defect‐assisted luminescence mechanism, attributing the fast emission (λ BL = 438 nm) to the negative‐pressure heating process during synthesis. Furthermore, the scintillator demonstrates consistent luminescence performance under intense irradiation conditions up to 563.5 mGy/s, indicating notable radiation resistance. These results highlight the promising potential of Cs 3 Cu 2 I 5 ‐AAO scintillation screens for applications in semiconductor defect inspection, biological tissue imaging, and 3D printing flaw detection.