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Title: Electron localization in rod-shaped triicosahedral gold nanocluster

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. There is little known about the carrier dynamics in these nanoclusters, which limit their energy-related applications. We reported the observation of exciton localization in triicosahedral Au37 nanoclusters (0.5 nm in diameter and 1.6 nm in length) by measuring femtosecond and nanosecond carrier dynamics. Upon photoexcitation to S1 electronic state, electrons in Au37 undergo ~100-ps localization from the two vertexes of three icosahedrons to one vertex, forming a long-lived S1* state. Such phenomenon is not observed in Au25 (dimer) and Au13 (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 -1 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 Au37 in the excited state induced by the strong coherent vibrations. The electron localization phenomenon we observed provides unique physical insight intomore » one-dimensional gold nanoclusters and other nanostructures, which will advance their applications in solar-energy storage and conversion.« less
Authors:
 [1] ;  [2] ; ORCiD logo [3] ;  [1] ;  [1] ; ORCiD logo [1]
  1. Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Chemistry
  2. Peking Univ., Beijing (China). College of Chemistry and Molecular Engineering
  3. Brookhaven National Lab. (BNL), Upton, NY (United States). Center for Functional Nanomaterials
Publication Date:
Report Number(s):
BNL-114330-2017-JA
Journal ID: ISSN 0027-8424; KC0403020
Grant/Contract Number:
SC0012704; AC02-98CH10886
Type:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 114; Journal Issue: 24; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Brookhaven National Lab. (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); US Air Force Office of Scientific Research (AFOSR)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; cluster; electron dynamics; electron localization; temperature dependence
OSTI Identifier:
1360862
Alternate Identifier(s):
OSTI ID: 1394759