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Title: Ultrafast Relaxation Dynamics of Au 38 (SC 2 H 4 Ph) 24 Nanoclusters and Effects of Structural Isomerism

Structural isomerism in nanoparticles has recently emerged as a new topic and stimulated research interest because the atomic structures of ultrasmall nanoparticles may have great impact on their fundamental properties and applications. We report the correlation between ultrafast relaxation dynamics and atomic structures of two isomers of thiolate-protected Au 38(SC 2H 4Ph) 24. The bi-icosahedral Au 38 (denoted as Au 38Q) with a Au 23 inner core in its atomic structure shows rapid decay (1.5 ps) followed by nanosecond relaxation to the ground state, whereas its structural isomer (Au 38T) exhibits similar relaxation processes, but the rapid decay is accelerated by ~50% (1.0 ps). The picosecond relaxations in both cases can be assigned to core–shell charge transfer or electronic rearrangement within the metal core. The acceleration of the fast decay in Au38T is ascribed to its unique core structure, which is made up of a mono-icosahedral Au 13 capped by a Au 12 tri-tetrahedron by sharing two atoms. Interestingly, coherent phonon emissions (25 cm –1 for Au 38Q, 27 and 60 cm –1 for Au 38T) are observed in both isomers with pumping in the NIR region. These results illustrate for the first time the importance of atomic structures inmore » the photophysics of same sized gold nanoclusters.« less
Authors:
 [1] ;  [2] ; ORCiD logo [1] ; ORCiD logo [3] ;  [2] ; ORCiD logo [1]
  1. Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Chemistry
  2. Chinese Academy of Sciences (CAS), Beijing (China). Key Lab. of Materials Physics, Anhui Key Lab. of Nanomaterials and Nanotechnology, CAS Center for Excellence in Nanoscience
  3. Brookhaven National Lab. (BNL), Upton, NY (United States). Center for Functional Nanomaterials
Publication Date:
Report Number(s):
BNL-114329-2017-JA
Journal ID: ISSN 1932-7447; KC0403020
Grant/Contract Number:
SC0012704
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 121; Journal Issue: 20; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
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)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Center for Functional Nanomaterials
OSTI Identifier:
1394758