Gap structure effects on surface-enhanced raman scattering intensities for gold gapped rods

Shuzhou Li, María L. Pedano, Shih Hui Chang, Chad A. Mirkin, George C. Schatz

Research output: Contribution to journalArticle

94 Citations (Scopus)

Abstract

Gapped rods provide a unique platform for elucidating structure/function relationships, both for single-molecule electrochemical techniques and for surface-enhanced Raman scattering (SERS). This paper attempts to elucidate the dependence of SERS intensities on gap topography and gap distance for gold gapped rods with segment lengths varying over a wide range (40-2000 nm). Significantly, we have determined that rough gaps lead to a smaller SERS enhancement than smooth gaps for these structures even though the rough gaps have a larger total surface area. Both theory and experiment show periodic variation of SERS intensity with segment length as determined by odd-symmetry plasmon multipoles. Excitation of even-symmetry modes is dipole forbidden (for polarization along the rod axis), but this selection rule can be relaxed by roughness or, for smooth gaps, by near-field coupling between the rod segments.

Original languageEnglish
Pages (from-to)1722-1727
Number of pages6
JournalNano letters
Volume10
Issue number5
DOIs
Publication statusPublished - May 12 2010

Keywords

  • Nanogap
  • Roughness
  • SERS

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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