Efficient single-phase tunable dual-color emission copper(I) scintillators for X-ray imaging

Hybrid copper(I) halides attract research interest for their broadband emission and high photoluminescence quantum yield (PLQY). In radiation detection, Cu(I) halide scintillators offer advantages such as low detection limits, high X-ray attenuation efficiency, and non-toxicity. In this study, using an aliphatic heterocyclic amine of morpholine (MPH) as the organic component, we have successfully synthesized three 1D [MPH]₄Cu₂X₆·H₂O (X = I, Br, Cl) single crystals (SCs) via acid solution volatilization crystallization. The obtained materials show similar 1D structures, with the fundamental unit of [Cu₂X₅]^3- (X = I, Br, Cl). Notably, [MPH]₄Cu₂I₆·H₂O (MCI) exhibits a characteristic excitation-dependent dual-band emission (525 nm and 691 nm) at room temperature and a high PLQY (83.02% for 525 nm and 36.89% for 691 nm). Theoretical calculations reveal that MCI possesses an indirect band gap, whereas [MPH]₄Cu₂X₆·H₂O (X = Br, Cl) has a direct band gap. Additionally, we explored the potential of MCI in X-ray imaging applications. With an optical yield of 38 467 photons per MeV and a 12 lp mm^-1 spatial resolution, the MCI wafer demonstrates significant potential for practical X-ray imaging.