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Title: Concerted growth and ordering of cobalt nanorod arrays as revealed by tandem in situ SAXS-XAS studies

The molecular and ensemble dynamics for the growth of hierarchical supercrystals of cobalt nanorods have been studied by in situ tandem X-ray Absorption Spectroscopy – Small Angle X-ray Scattering (XAS - SAXS). The super-crystals were obtained by reducing a Co(II) precursor under H 2 in the presence of a long chain amine and a long chain carboxylic acid. Complementary time-dependent ex situ TEM studies were also performed. The experimental data provide critical insights into the nanorod growth mechanism, and unequivocal evidence for a concerted growth-organization process. Nanorod formation involves cobalt nucleation, a fast atom by atom anisotropic growth and a slower oriented attach-ment process that continues well after cobalt reduction is complete. As a result, smectic-like ordering of the nanorods appears very early in the process, as soon as nanoparticle elongation appears, and nanorod growth takes place inside organized super-lattices, which can be regarded as mesocrystals.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [3] ;  [1] ;  [4] ;  [2] ;  [1]
  1. Univ. de Toulouse, Toulouse (France)
  2. Argonne National Lab. (ANL), Argonne, IL (United States)
  3. Univ. de Toulouse, Toulouse (France); Argonne National Lab. (ANL), Argonne, IL (United States)
  4. Argonne National Lab. (ANL), Argonne, IL (United States); Purdue Univ., West Lafayette, IN (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 138; Journal Issue: 27; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1339959