Ligand Engineering of Copper(I) Iodide Complexes for Fabricating Transparent and Monolithic Glass Scintillators for High-Resolution X-ray Imaging

This study demonstrates a ligand design strategy to modulate the glass-forming ability of binuclear Cu2I2–diphosphine complexes, enabling the fabrication of transparent monolithic glass scintillators for high-resolution X-ray imaging. By elongating the flexible alkyl chain of diphosphine ligands, the melting points of the crystalline complexes were significantly reduced from 290 °C to ∼223 °C, while their decomposition temperatures remained above 380 °C. This effectively widened the processing window, facilitating successful melt-quenching into stable glasses. The resulting glasses exhibited high optical transparency (>84% in the visible range), a robust glass state stable up to 120 °C, and excellent water resistance. X-ray-excited luminescence and imaging tests revealed that the glass from [Cu2I2(dpph)2] achieved a light yield of 8570 photons MeV–1 and a high spatial resolution of 30 lp mm–1. This work establishes a versatile ligand engineering approach for developing processable, high-performance metal–organic glass scintillators.