Journal of Physical Chemistry A, Vol.122, No.35, 7014-7022, 2018
A Single Model for the Excited-State Dynamics of Au-18(SR)(14) and Au-25(SR)(18) Clusters
Excited-state properties of photonic materials play an important part in dictating the photocatalytic activity. Thiol-protected gold clusters, like Au-18(SR)(14 )and Au-25(SR)(18), are an emerging material of interest with unique optical and electronic properties. Au-18(SR)(14) clusters, in particular, have shown promise as one of the highest efficiency clusters in light harvesting, with a high emission quantum yield. In this work, the excited-state properties of Au-18(SR)(14) are studied in-depth by ultrafast pump/probe spectroscopy for the first time. A single model describing the optical characteristics of thiol-protected Au-18(SR)(14 )and Au-25(SR)(18) clusters is offered. Excited-state dynamics analysis suggests that there are state-resolved relaxations due to the presence of multiple excited states. The populations of these excited states are shown to be solvent- and ligand-dependent.