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Adsorption of 4,4′‐biphenyl diisocyanide on gold nanoparticle surfaces investigated by surface‐enhanced Raman scattering
Author(s) -
Joo SangWoo,
Kim WanJoong,
Yoon Wan Soo,
Choi Insung S.
Publication year - 2003
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.994
Subject(s) - adsorption , colloidal gold , raman scattering , biphenyl , raman spectroscopy , nanoparticle , chemistry , particle (ecology) , analytical chemistry (journal) , materials science , nanotechnology , optics , organic chemistry , physics , oceanography , geology
We investigated the spectral features of the ν(NC) bands when 4,4′‐biphenyl diisocyanide (BPDNC) is adsorbed on gold nanoparticle surfaces by surface‐enhanced Raman scattering (SERS). The mode of adsorption of BPDNC on gold nanoparticles was found to change with the bulk concentration. At low concentrations of BPDNC, only the ν(NC) bound band was conspicuous at ∼2185 cm −1 and the free NC stretching band was barely detected in the SERS spectra. When the bulk concentration was increased, the ν(NC) free band became prominent at ∼2123 cm −1 . BPDNC was assumed to bridge two different gold particles at low concentrations, but as the concentration was increased, the bridge appeared to be broken and bonded to the gold particle only via one of the two isocyanide groups. On the basis of the electromagnetic surface selection rule, we attempted to explain the orientation of the adsorbate on Au surfaces by determining the relative enhancement factor of each vibrational band. Copyright © 2003 John Wiley & Sons, Ltd.