Electron localization in rod-shaped triicosahedral gold nanocluster

Abstract

Atomically precise gold nanocluster based on linear assembly of repeating icosahedrons (clusters of clusters) is a unique type of linear nanostructure, which exhibits strong near-infrared absorption as their free electrons are confined in a one-dimensional quantum box. Little is known about the carrier dynamics in these nanoclusters, which limit their energy-related applications. Here, we reported the observation of exciton localization in triicosahedral Au nanoclusters (0.5 nm in diameter and 1.6 nm in length) by measuring femtosecond and nanosecond carrier dynamics. Upon photoexcitation to S electronic state, electrons in Au undergo ∼100-ps localization from the two vertexes of three icosahedrons to one vertex, forming a long-lived S* state. Such phenomenon is not observed in Au (dimer) and Au (monomer) consisting of two and one icosahedrons, respectively. We have further observed temperature dependence on the localization process, which proves it is thermally driven. Two excited-state vibration modes with frequencies of 20 and 70 cm observed in the kinetic traces are assigned to the axial and radial breathing modes, respectively. The electron localization is ascribed to the structural distortion of Au in the excited state induced by the strong coherent vibrations. The observed electron localization phenomenon provides unique physical insight into one-dimensional gold nanoclusters and other nanostructures, which will advance their applications in solar-energy storage and conversion.

Gold Nanoclusters: Bridging Gold Complexes and Plasmonic Nanoparticles in Photophysical Properties

“…Two frequencies (40 cm −1 and 80 cm −1 ) were exhibited at different probe wavelengths ( Figure 6D), which have been reported previously [51]. These oscillations observed in TA decays, also observed in other nanoclusters [52,53], were assigned to acoustic vibrations of the metal core and explained as displacive excitation [52,54], similar to that observed in semiconductors and small molecules [54,55].…”

Insight into the Geometric and Electronic Structures of Gold/Silver Superatomic Clusters Based on Icosahedron M13 Units and Their Alloys

“…As a building block, this unit can be assembled into different supramolecular structures by controlling the capping ligands . Different assembly forms of the M 13 unit not only contribute to the construction of superatomic aggregates with novel structures, but also have a remarkable effect on the optical, catalytic, and other properties of the superatomic aggregates . This greatly encourages us to continue exploring the superatomic assembly of M 13 elements …”

“…In this review, we focus on gold/silver metal superatomic clusters based on the assembly of M 13 units, which have become a new class of nanomaterial and shown intriguing properties . Benefiting from single‐crystal X‐ray crystallography, the well‐determined structures have explicitly revealed the surface structure, the type of bonding, and the assembly method for nanoclusters consisting of M 13 units .…”

“…[38][39][40][41][42][43][44][45][46] Differenta ssembly forms of the M 13 unit not only contribute to the construction of superatomic aggregates with novel structures, buta lso have ar emarkable effect on the optical, catalytic, and other properties of the superatomic aggregates. [45][46][47] This greatlye ncourages us to continue exploring the superatomic assembly of M 13 elements. [38][39][40][41][42][43][44][45][46][47] In this review,w ef ocus on gold/silver metal superatomic clusters based on the assembly of M 13 units, whichh ave become an ew class of nanomaterial and shown intriguing properties.…”

Correspondence: Reply to ‘On the bonding in ligand-protected gold clusters’

“…Summary and perspective : With introducing two groups of elementary blocks in the GUM, Au 3 (2 e ), and Au 4 (2 e ), a variety of ligand-protected gold nanoclusters, e.g., spherical and non-spherical, or magic-number and non-magic-number, can be viewed as an aggregate of the elementary groups by applying electron counting rule, a notion analog to Mingo’s united atom model for understanding weakly bound condensed icosahedra with 8 e valence electrons for each unit 7 . A recent experiment showed that the localization effect is highly important for the interpretation of the spectroscopy of gold nanoclusters 8 . Moreover, the triangle Au 3 and tetrahedral Au 4 can be considered as the basic units of face-centered cubic bulk gold.…”