Abstract
Luminescentcopper halide clusters have attracted wide attentionin light-emitting diodes and optical sensors due to their intriguingphysicochemical properties and diverse chemical structures. Recently,the clusters have also been explored as promising scintillation materialsdue to the heavy copper halide cores that provide a large absorptioncross section for X-ray radiation. However, the related research oncopper halide cluster scintillators is only in its infancy, and thescintillation performance of the clusters still lags behind that ofperovskite and its related metal halide structures. Here we report0D cubane-like Cu4I4(L)(4) (L = 4-benzylpyridineor 4-tert-butylpyridine) clusters with broad emissionband, high photoluminescence quantum yield (>85%), and a largeStokesshift. Density functional theory calculations demonstrate that theemission of both clusters mainly originates from the ligand-to-corecharge transfer state. Besides, we successfully synthesized the colloidalcluster microcrystals and fabricated microcrystal-based films forX-ray imaging applications. We found that the cluster-based X-rayscreens exhibited high light yields (>30000 photons MeV-1), low detection limits (<150 nGy s(-1)), andexcellent spatial resolutions exceeding 20 lp mm(-1), surpassing the resolution of the most common commercial scintillators.We believe that this work provides the foundation for the furtherdevelopment of high-performance copper cluster-based scintillators.