Engineered Excited-State Coupling Enables Efficient Exciton Harvesting in Copper-Cluster Scintillators
Xudong Hu a, Omar Mohammed a
a Center for Renewable Energy and Storage Technologies (CREST), Division of Physical Science and Engineering (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia.
Proceedings of Emerging Light Emitting Materials 2026 (EMLEM26)
Kallithea, Greece, 2026 September 20th - 23rd
Organizers: Maryna Bodnarchuk, Grigorios Itskos and Maksym Kovalenko
Poster, Xudong Hu, 056
Publication date: 8th July 2026

Environmentally benign scintillators with broadband radioluminescence are highly desirable for low-cost, high-performance X-ray imaging. Recently, copper iodide (Cu-I) clusters have emerged as promising candidates owing to strong spin-orbit coupling, favorable solution processability, excellent X-ray absorption efficiency and efficient exciton harvesting enabled by aggregation-induced emission and thermally activated delayed fluorescence. However, the mechanism by which aggregation-state variation enhances the light yield by modulating intermolecular interactions remains poorly understood. Here, we establish a pair of isomeric Cu–I clusters with nearly identical X-ray attenuation coefficients as a model platform to isolate and elucidate the role of intermolecular coupling. In this context, we uncover a breakthrough mechanistic picture in which engineered excited-state coupling accelerates carrier relaxation and promotes efficient exciton harvesting and radiative recombination. Guided by this mechanism, water-resistant cluster scintillator glasses with excellent processing flexibility are fabricated, delivering a high light yield of 32,456 photons MeV-1 and a very impressive spatial resolution of 33.6 lp mm-1. Furthermore, tandem integration with a high-Z scintillator enables selective density-discriminating X-ray imaging and micro-computed tomography. This work provides mechanistic guidance for ligand engineering in the design of efficient cluster scintillators and facilitates the high-throughput development of promising metal-cluster complexes for advanced optoelectronic applications.

This work was financially supported by the by the National Natural Science Foundation of China (U23A20359, 62222405), and the Fundamental Research Funds for the Central Universities (No.2026201010). For computer time, this research used Shaheen III managed by the Supercomputing Core Laboratory at King Abdullah University of Science & Technology (KAUST) in Thuwal, Saudi Arabia.

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