Regulation of the photophysical dynamics of metal nanoclusters by manipulating single-point defects

Abstract Metal nanoclusters have served as an emerging class of programmable nanomaterials with customized structures. However, it remains highly challenging to achieve the single-atom regulation of metal nanoclusters without altering their structural frameworks. Here, we achieve the single-point defects manipulation based upon a cluster pair of Au 21 and Au 22 by meticulously complementing the surface defects of the former nanocluster with an additional single-Au complex. The two nanoclusters exhibited identical geometric structures, but their pronounced quantum-confinement effects resulted in different electronic properties, evident in their distinct optical absorption and emission characteristics. Temperature-dependent steady-state photoluminescence spectra and femtosecond transient absorption spectra showed that the manipulation of a single-point defect in Au 22 inhibited non-radiative decay pathways, reduced electron loss at higher energy levels, and accelerated intersystem crossing, which ultimately enhanced its emission intensity. Overall, the Au 21 and Au 22 cluster system in this study provides a cluster platform with controllable surface single-point defects, enabling the regulation of the photophysical dynamics at the atomic level.