Characterization of Silane-Modified Immobilized Gold Colloids as a Substrate for Surface-Enhanced Raman Spectroscopy

Immobilized gold colloid particles coated with a C-18 alkylsilane layer have been characterized as a substrate for surface-enhanced Raman scattering (SERS) studies of adsorption onto hydrophobic surfaces. Atomic force microscopy images, optical extinction spectra, and SERS measurements are reported...

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Bibliographic Details
Published in:Analytical chemistry (Washington) 2001-09, Vol.73 (17), p.4268-4276
Main Authors: Olson, Lydia G, Lo, Yu-Shui, Beebe, Harris, Joel M
Format: Article
Language:English
Subjects:
Absorption
Atoms & subatomic particles
Chemistry
Colloidal particles
Colloids
Exact sciences and technology
Fluids
General and physical chemistry
Gold
Metals
Raman spectroscopy
Scientific imaging
Solid-liquid interface
Surface physical chemistry
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Summary:Immobilized gold colloid particles coated with a C-18 alkylsilane layer have been characterized as a substrate for surface-enhanced Raman scattering (SERS) studies of adsorption onto hydrophobic surfaces. Atomic force microscopy images, optical extinction spectra, and SERS measurements are reported as a function of accumulation of gold colloid on glass. As the metal particles become increasingly aggregated on the surface, the SERS enhancement increases until the plasmon resonance shifts to wavelengths longer than the excitation laser. The gold colloid substrates are stable and exhibit reproducible SERS enhancement. When octadecyltrimethoxysilane is self-assembled over the gold, the metal surface is protected from exposure to solution-phase species, as evidenced by the inhibition of chemisorption of a disulfide reagent to the overcoated gold surface. The results show that interactions with gold can be blocked by a silane layer so as not to significantly influence physisorption of molecules at the C-18/solution interface. The SERS enhancement from these C-18-overcoated gold substrates is reproducible for different films prepared from the same colloidal suspension; the substrates are also stable with time and upon exposure to laser irradiation.
ISSN:0003-2700
1520-6882
DOI:10.1021/ac000873b