A highly luminescent copper(i) halide complex scintillator for X-ray imaging applications

Abstract

Copper(I) halide complexes have garnered much attention due to their straightforward synthesis, high luminescence efficiency, and structural diversity. In this work, a new class of Cu₂X₂L₂ complexes (X = Cl, Br, and I and L = 2-(dicyclohexyl)-2-(N,N-dimethylamino) biphenyl) were synthesized. Among them, the Cu₂I₂L₂ complex exhibits a broad emission band and a high photoluminescence quantum yield of nearly 100%. Time-dependent density functional theory calculations reveal that the emission of Cu₂I₂L₂ stems primarily from the mixed metal/halogen-to-ligand charge transfer state. Notably, the Cu₂I₂L₂ complex exhibits a light yield of 38 297 photons MeV⁻¹ and an ultra-low detection limit of 49.4 nGy s⁻¹. The scintillation film fabricated from Cu₂I₂L₂ enables high-resolution X-ray imaging with a spatial resolution of 10 lp mm⁻¹. These results underscore the promising potential of Cu₂I₂L₂ as an excellent scintillator for advanced X-ray imaging applications.