Boosting Triplet Fusion Upconversion Performance via Triplet-Mediator-Decorated Au13 Nanoclusters

Abstract Metal nanoclusters (NCs) hold great promise as triplet sensitizers for triplet–fusion upconversion. Here, we boost the performance of [Au13(dppe)5R2]3+ by integrating a triplet-mediator ligand, R = C≡C–DPA (DPA = 9,10-diphenylanthracene). This strategic decoration resulted in an 850-fold acceleration in intermolecular energy transfer and a 38-fold increase in the reabsorption-corrected upconversion quantum yield compared to the phenyl-terminated counterpart. This study establishes surface-mediator pathways as crucial for bypassing the bulky ligand shell that protects the metal core in NC sensitizers.