SupramolecularlyStabilized Copper(I) Halides forHigh-Efficiency Near-Ultraviolet Emission and X-ray Scintillation

Near-ultraviolet (NUV)-emissive materials are crucial for advanced photonic technologies and high-resolution scintillators. However, existing NUV-emitting materials face challenges in balancing efficiency, stability, and scalability for broad optoelectronic applications. Herein we report two supramolecularly confined copper(I) halide hybrids featuring trigonal-planar coordination environments stabilized by a cryptand host, which exhibit intense NUV emission with near-unity photoluminescence quantum yields, large Stokes shifts, and characteristic self-trapped exciton emission. Remarkably, both compounds demonstrate notable X-ray scintillation performance with an ultralow detection limit of 0.55 μGy s–1, approximately an order of magnitude lower than that required for standard medical diagnostic imaging, highlighting their superior sensitivity for low-dose radiation detection. Importantly, they can be synthesized via both solution crystallization and solvent-free mechanochemical routes, enabling high-quality single-crystal growth and scalable production. The present study introduces a new supramolecular approach to stabilizing low-coordinate Cu(I) halides, opening a structural pathway toward wide-bandgap lead-free emitters and high-performance violet-emissive scintillators.