Abstract: Gold nanoclusters (size< 2.2 nm) bridge metallic gold nanoparticles and single gold atoms, playing a crucial role in revealing the origin of surface plasmon resonance and metallic bonding. Ligand-protected gold nanoclusters provide a suitable platform to understand metal to non-metal transitions while the excited-state dynamics of gold nanoclusters in the transition regime remain elusive. In this minireview, I summarize the excite-state dynamics of large-sized Aun (n>100) nanoclusters and compare them with those of plasmonic gold nanoparticles. By looking into the electron and vibration dynamics of a series of thiolate-protected gold nanoclusters in the transition regime, the electronic structures of these nanoclusters are further discussed. A deeper understanding of the mechanism of electron relaxation and energy dissipation of large-sized gold nanoclusters will be of great help to connect the optical properties of metal clusters and nanoparticles, which will further promote the design of those functional nanomaterials.

Key words: gold nanoclusters, excited-state dynamics, electronic structure, surface plasmon resonance