Zero-Dimensional Hybrid Cuprous Iodide Clusters for X-ray Imaging

Metal halide clusters have recently emerged as promising scintillators for X-ray detection and imaging owing to their high X-ray absorption coefficients, excellent environmental stability, and tunable luminescence. Here, we report two zero-dimensional (0D) hybrid cuprous iodide clusters, (4-popy) 4 Cu 2 I 2 and (4-popy) 4 Cu 4 I 4 (4-popy = 4-phenoxypyridine, C 11 H 9 NO), featuring isolated [Cu 2 I 2 ] rhomboid dimers and [Cu 4 I 4 ] cubane tetramers for X-ray detection and imaging. Due to the unique 0D configurations, both clusters exhibit broadband emissions, large Stokes shifts, and near-unity photoluminescence quantum yields. Notably, the (4-popy) 4 Cu 4 I 4 clusters, benefiting from their higher effective atomic number and denser framework, demonstrate an exceptional X-ray light yield of 52,000 photons·MeV –1 . Embedded into a poly(vinyl alcohol) matrix, flexible scintillation films based on (4-popy) 4 Cu 4 I 4 clusters achieve a low X-ray detection limit of 167 nGy·s –1 and a high spatial resolution of X-ray imaging up to 20 lp·mm –1 . These results establish hybrid cuprous iodide clusters as a promising class of solution-processable and high-performance scintillators for low-dose, high-resolution X-ray imaging.