Evolution from the plasmon to exciton state in ligand-protected atomically precise gold nanoparticles

Abstract

The evolution from the metallic (or plasmonic) to molecular state in metal nanoparticles constitutes a central question in nanoscience research because of its importance in revealing the origin of metallic bonding and offering fundamental insights into the birth of surface plasmon resonance. Previous research has not been able to probe the transition due to the unavailability of atomically precise nanoparticles in the 1–3 nm size regime. Herein, we investigate the transition by performing ultrafast spectroscopic studies on atomically precise thiolate-protected Au25, Au38, Au144, Au333, Au∼520 and Au∼940 nanoparticles. Our results clearly map out three distinct states: metallic (size larger than Au333, that is, larger than 2.3 nm), transition regime (between Au333 and Au144, that is, 2.3–1.7 nm) and non-metallic or excitonic state (smaller than Au144, that is, smaller than 1.7 nm). The transition also impacts the catalytic properties as demonstrated in both carbon monoxide oxidation and electrocatalytic oxidation of alcohol.

Ultrafast Electron Dynamics in Thiolate-Protected Plasmonic Gold Clusters: Size and Ligand Effect

“…Increasing pump energy will heat up more electrons and decelerating the e-p coupling leads to slowing down of electron relaxation. 52,80 The pump-power dependence of bleach recovery can be modeled using a two-temperature model: [81][82][83][84]…”

“…The normalized bleach recovery (-Norm. ΔA) for the investigated clusters is shown in Figure 4 A-F. To extract electron-phonon relaxation for each cluster, the bleach recovery dynamics was fitted (see Figure 4) using: 52 Table 1. Figure 5A shows the plot of calculated at different pump energies for Au279 (TBBT), Au329 (SC2Ph), Au329 (SC6) and Au13 nm (Citrate) nanoparticles.…”

“…In a recent work, e-p dynamics of the different sized gold nanoparticles conjugated with the chemical-ligand has been studied. 52 By mapping the bleach recovery dynamics of these nanoparticles, Zhou et. al.…”

Atomically Precise Gold Nanoclusters Accelerate Hydrogen Evolution over MoS2 Nanosheets: The Dual Interfacial Effect

“…Recently, thiolate‐protected gold nanoclusters—Au n (SR) m (where n and m represent the numbers of gold atoms and thiolate ligands, respectively)—have emerged as a new class of nanomaterials and hold promising applications in areas such as photovoltaics, sensing, catalysis, optics, etc. Gold nanoclusters of different magic sizes have been obtained and the atomic structures of some of the gold nanoclusters have been elucidated by single crystal X‐ray diffraction analysis .…”

Catalytic Amplification of Au144 Nanocluster Collisions by Hydrogen Evolution Reaction

“…The size and charge state of NCs are essential factors influencing their catalytic activities, as demonstrated for oxygen and carbon dioxide electroreductions at Au nanoclusters. [6,7,[9][10][11] The atomic NCs typically exhibit high monodispersity [12] and well-defined molecular composition. [7] While larger NPs with long-chain capping ligands tend to be catalytically inert; [8] the NCs capped with a long chain surfactant can effectively catalyze surface reactions, though the activation mechanism in this case is largely unknown.…”