Adsorption characteristics of 4,4′-bipyridine molecules on gold nanosphere films studied by surface-enhanced Raman scattering

Mototsugu Suzuki, Yasuro Niidome, Sunao Yamada

    Research output: Contribution to journalArticlepeer-review

    41 Citations (Scopus)

    Abstract

    We have measured and compared the surface-enhanced Raman scattering (SERS) spectra of 4,4′-bipyridine (bpy) molecules deposited (adsorbed) on the films of gold nanospheres (NSs, mean diameter 35 ± 5 nm), as prepared by the salting-out method using NaClO4 and NaOH. The bpy-deposited (adsorbed) films were prepared by casting an aliquot of the bpy-ethanol solutions in different concentrations (less and above the monolayer converge on the gold surface), or on immersion of the NS films into the concentrated bpy solution. The enhancement of the SERS spectra of bpy was larger for the NS film prepared from NaClO4 than that from NaOH. But, the SERS intensity was independent of the concentration of the bpy solution. The changes in the intensities and the shapes of the SERS spectra were distinctly observed on immersion of the bpy-deposited (adsorbed) NS films into pure ethanol, and these spectral changes were prominent for the NS film prepared from NaClO4. This must be attributed to considerably coalesced structures of the NS film prepared from NaClO4. From the comparison of the intensity changes before and after immersion into ethanol, it is suggested that the vertical orientation of the bpy molecules adsorbed on the NS films changes into the flat orientation with respect to the surface of the gold nanoparticles at the solid-liquid interface, on immersion of the film into pure ethanol.

    Original languageEnglish
    Pages (from-to)740-747
    Number of pages8
    JournalThin Solid Films
    Volume496
    Issue number2
    DOIs
    Publication statusPublished - Feb 21 2006

    All Science Journal Classification (ASJC) codes

    • Electronic, Optical and Magnetic Materials
    • Surfaces and Interfaces
    • Surfaces, Coatings and Films
    • Metals and Alloys
    • Materials Chemistry

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