Dimethylamine Copper(I) Halide Single Crystals: Structure, Physical Properties, and Scintillation Performance

Hybrid copper(I) halides have garnered a significant amount of attention as potential substitutes in luminescence and scintillation applications. Herein, we report the discovery and crystal growth of new zero-dimensional compounds, (C₂H₈N)₃Cu₂I₅ and (C₂H₈N)₄Cu₂Br₆. The bromide and iodide have a triclinic structure with space group P1̅ and an orthorhombic structure with space group Pnma, respectively. (C₂H₈N)₃Cu₂I₅ exhibits cyan emission peaking at 504 nm with a photoluminescence quantum yield (PLQY) of 34.79%, while (C₂H₈N)₄Cu₂Br₆ shows yellowish-green emission peaking at 537 nm with a PLQY of 38.45%. The temperature-dependent photoluminescence data of both compounds were fitted to theoretical models, revealing that nonradiative intermediate states significantly affect thermal quenching and antiquenching. Electron-phonon interactions, the origin of emission line width broadening and peak shifting, were also investigated via fittings. The scintillation properties of (C₂H₈N)₃Cu₂I₅ were evaluated, and an X-ray imaging device was successfully fabricated using (C₂H₈N)₃Cu₂I₅. This work demonstrates the potentiality of copper halides in lighting and X-ray imaging applications.