Supramolecularly Stabilized Copper(I) Halides for High-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.