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Title: Au 329–xAg x(SR) 84 Nanomolecules: Plasmonic Alloy Faradaurate-329

Though significant progress has been made to improve the monodispersity of larger (>10 nm) alloy metal nanoparticles, there still exists a significant variation in nanoparticle composition, ranging from ±1000s of atoms. Here in this paper, for the first time, we report the synthesis of atomically precise (±0 metal atom variation) Au 329–xAg x(SCH 2CH 2Ph) 84 alloy nanomolecules. The composition was determined using high resolution electrospray ionization mass spectrometry. In contrast to larger (>10 nm) Au–Ag nanoparticles, the surface plasmon resonance (SPR) peak does not show a major shift, but a minor ~10 nm red-shift, upon increasing silver content. The intensity of the SPR peak also varies in an intriguing manner, where a dampening is observed with medium silver incorporation, and a significant sharpening is observed upon higher Ag content. The report outlines (a) an unprecedented advance in nanoparticle mass spectrometry of high mass at atomic precision; and (b) the unexpected optical behavior of Au–Ag alloys in the region where nascent SPR emerges; specifically, in this work, the SPR-like peak does not show a major ~100 nm blue-shift with Ag alloying of Au 329 nanomolecules, as shown to be common in larger nanoparticles.
 [1] ;  [2] ;  [3] ;  [1]
  1. Univ. of Mississippi, Oxford, MS (United States). Department of Chemistry and Biochemistry
  2. Argonne National Lab. (ANL), Argonne, IL (United States). X-ray Science Division, Advanced Photon Source
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division
Publication Date:
Grant/Contract Number:
AC05-00OR22725; AC02-06CH11357
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry Letters
Additional Journal Information:
Journal Volume: 6; Journal Issue: 16; Journal ID: ISSN 1948-7185
American Chemical Society
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; alloy metal nanoparticles; electrospray ionization mass spectrometry; surface plasmon resonance
OSTI Identifier: