Recent Advances in Long-Lived Emission in Coinage Metal Nanoclusters: Implications for Optoelectronic Applications

The emerging research area of ultrasmall, luminescent coinage metal nanoclusters exhibiting delayed emission through thermally-activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) has garnered considerable interest in diverse applications such as imaging, therapy, and optoelectronics. To utilize the metal nanoclusters for advanced applications, it is crucial to understand the excited state dynamics governing delayed emission. Here, we comprehensively review the recent advancement in the design strategies of metal nanoclusters aimed at achieving control over their long-lived luminescence. The design strategies include solvent-induced aggregation, crystallization-induced self-assembly, complexation methods, ligand engineering, metal core doping, and composition regulation. Through these strategies, long-lived emission can be achieved which can provide TADF and RTP luminescence mechanism. Our primary goal is to harness the versatile capabilities of long-lived metal nanoclusters to advance their optoelectronic properties and broaden their range of practical applications.