Tuning photoelectron dynamic behavior of thiolate-protected MAu24 nanoclusters via heteroatom substitution

Heteroatom substitution of gold nanoclusters enables precise tuning of their physicochemical properties at the single-atom level, which has a significant impact on the applications related to excited states including photovoltaics, photocatalysis and photo-luminescence. To this end, understanding the effect of metal exchange on the structures, electronic properties and photoexcited dynamic behavior of nanoclusters is imperative. Combining density functional theory with time-domain nonadiabatic molecular dynamics simulations, herein we explored the effect of metal replacement on the electronic and vibrational properties as well as excited-state dynamics of ligand-protected MAu24(SR)(18) (M = Pd, Pt, Cd, and Hg) nanoclusters. At the atomistic level, we elucidate hot carrier relaxation and recombination dynamic behavior with various doping atoms. Such distinct excited-state behavior of MAu24(SR)(18) nanoclusters is attributed to different energy gaps and electron-phonon coupling between the donor and acceptor energy levels, owing to the perturbation of nanoclusters by a single foreign atom. The specific phonon modes involved in excited-state dynamics have been identified, which are associated with the MAu12 core and ligand rings. This time-dependent excited-state dynamic study fills the gap between structure/composition and excited-state dynamic behavior of MAu24(SR)(18) nanoclusters, which would stimulate the exploration of their applications in photoenergy storage and conversion.

Automated summary

Heteroatom substitution of gold nanoclusters allows for precise tuning of their physicochemical properties at the single-atom level, which has significant implications for applications related to excited states. In this study, the effect of metal exchange on the electronic and vibrational properties as well as excited-state dynamics of ligand-protected MAu24(SR)(18) nanoclusters was investigated using density functional theory and time-domain nonadiabatic molecular dynamics simulations.