Work

Characterization of SiO2-Overcoated Silver-Island Films as Substrates for Surface-Enhanced Raman Scattering

Year: 1996

Type: article

Abstract: Vapor deposition of a 45-Å layer of silver and a subsequent 50−65-Å layer of SiO 2 onto a glass slide is shown to be a viable substrate for surface-enhanced Raman spectroscopy (SERS) and a model of the silica surface suitable for adsorption kinetic studies. The chemistry of the silica is characterized by UV absorption and contact angle measurements. The physical structure is probed by atomic force microscopy to compare the surface roughness of the silver-island film and its SiO 2 overcoat. Auger electron spectroscopy and X-ray photoelectron spectroscopy are used to probe the silica layer for exposure of silver through gaps in the overcoat. Comparison of SERS of dibenzyl disulfide bound to a silver-island film versus that of a silver film protected by the SiO 2 overlayer tests the continuity of the SiO 2 film and its ability to block access of adsorbates to the underlying silver surface. The model silica surface is used to detect the Raman spectrum of adsorbed pyridine and its adsorption isotherm; the adsorbate vibrational frequencies are consistent with previous reports of pyridine on silica.

Source: Analytical Chemistry

DOI: 10.1021/ac950860b

Authors: William B. Lacy, John M. Williams, Lisa A. Wenzler, Thomas P. Beebe, Joel M. Harris

Institution: University of Utah

Language: English

Topic: Gold and Silver Nanoparticles Synthesis and Applications

Subfield: Electronic, Optical and Magnetic Materials

Field: Materials Science

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, U.S. Department of Energy, Division of Chemistry

Awards: NEW GRANT - TIME RESOLVED ANALYTICAL METHODS FOR LIQUID/SOLID INTERFACES P.I. - JOEL M. HARRIS, NSF Young Investigator/Structure and Reactivity of Molecules on Surfaces