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This content will become publicly available on November 22, 2018

Title: On the Non-Metallicity of 2.2 nm Au 246 (SR) 80 Nanoclusters

The transition from molecular to plasmonic behaviour in metal nanoparticles with increasing size remains a central question in nanoscience. Here, we report that the giant 246-gold-atom nanocluster (2.2 nm in gold core diameter) protected by 80 thiolate ligands is surprisingly non-metallic based on UV/Vis and femtosecond transient absorption spectroscopy as well as electrochemical measurements. Specifically, the Au246 nanocluster exhibits multiple excitonic peaks in transient absorption spectra and electron dynamics independent of the pump power, which are in contrast to the behaviour of metallic gold nanoparticles. Moreover, a prominent oscillatory feature with frequency of 0.5 THz can be observed in almost all the probe wavelengths. The phase and amplitude analysis of the oscillation suggests that it arises from the wavepacket motion on the ground state potential energy surface, which also indicates the presence of a small band-gap and thus non-metallic or molecular-like behaviour.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [2] ; ORCiD logo [3] ;  [1] ;  [1]
  1. Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Chemistry
  2. Georgia State Univ., Atlanta (Georgia). Dept. of Chemistry
  3. Brookhaven National Lab. (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)
Publication Date:
Report Number(s):
BNL-203329-2018-JAAM
Journal ID: ISSN 1433-7851
Grant/Contract Number:
SC0012704; FA9550-15-1-9999; FA9550-15-1-0154; AC02-98CH10886
Type:
Accepted Manuscript
Journal Name:
Angewandte Chemie (International Edition)
Additional Journal Information:
Journal Name: Angewandte Chemie (International Edition); Journal Volume: 56; Journal Issue: 51; Journal ID: ISSN 1433-7851
Publisher:
Wiley
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
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; 77 NANOSCIENCE AND NANOTECHNOLOGY; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; electron dynamics; gold; nanoparticles; photophysics; ultrafast spectroscopy
OSTI Identifier:
1426449
Alternate Identifier(s):
OSTI ID: 1410131