Copper Iodide Ink Scintillator‐Based X‐Ray Detector for High‐Resolution Computed Tomography Imaging

Computed tomography (CT) employs X‐ray beams to acquire multi‐angle projections, enabling slice images and 3D structures of objects via computational algorithms. This overcomes the structural superimposition inherent in conventional 2D X‐ray imaging, finding broad applications in medical diagnostics and industrial inspection. Copper halide inks have emerged as promising scintillators due to their structural tunability and favorable photophysical properties. However, their potential for high‐resolution CT imaging remains underexplored. Here, we report a solution‐processable (PTMA) 3 Cu 3 I 6 (PTMA = phenyltrimethylammonium) ink with broadband yellow emission, high photoluminescence quantum yield, a large Stokes shift, and microsecond‐scale lifetime. Density functional theory calculations confirm the emission arises from ligand‐to‐core charge transfer. Moreover, the copper halide achieves 164% light output relative to Bi 4 Ge 3 O 12 , excellent dose linearity, and strong radiation stability. A uniform, large‐area scintillation layer with tunable thickness is then fabricated via spray coating. A prototype X‐ray detector based on the sprayed scintillation layer attains a spatial resolution of 7.0 lp mm −1 with a pixel size of 49.5 µm. As a result, high‐resolution tomographic slices and 3D structural reconstruction images based on fish samples are achieved using the self‐built tabletop CT system, demonstrating the capability of solution‐processable copper halide ink scintillators for CT imaging applications.