Ligand-Regulated Long-Lived Charge Transfer Dynamics in Atomically Precise Metal Nanoclusters

Ligand-mediated long-lived charge transfer (CT) represents a promising mechanism for harvesting excitons in atomically precise metal nanoclusters (NCs), paving the way for highly efficient applications in photocatalysis, photovoltaics, and artificial photosynthesis. Despite its significance, the intricate role of ligands in modulating long-lived CT dynamics in excited metal NCs remains poorly understood. Herein, we establish foundational principles for ligand engineering to elucidate the kinetics of long-lived CT. Our findings reveal that incorporating bulky ligands significantly mitigates the attenuation of charge separation rates while concurrently increasing the decay rates of charge recombination, resulting in markedly enhanced charge separation efficiency. As a consequence, metal NCs with bulky ligands demonstrate improved generation efficiency of reactive oxygen species and increased photocurrent intensity. These insights not only clarify the longstanding debate surrounding the influence of small-sized ligands on the light-conversion efficiency of metal NCs but also advance their potential as effective light harvesters in cutting-edge technologies.