Estimation of dielectric function of biotin-capped gold nanoparticles via signal enhancement on surface plasmon resonance

Xinheng Li, Kaoru Tamada, Akira Baba, Wolfgang Knoll, Masahiko Hara

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Biotin-capped gold nanoparticles assembled on flat gold with volume fraction/are studied by surface plasmon resonance (SPR) spectroscopy and atomic force microscopy (AFM) in order to estimate the dielectric function of the gold nanoparticles based on the Maxwell-Garnett (MG) theory. The complex dielectric function (∈′, ∈″) of the spherical nanoparticles at three representative wavelengths in the vis-near-IR region, i.e., λ = 543, 632.8, and 1152 nm, is estimated for a surface homogeneously covered with nanoparticles in order to discuss the wavelength dependence of the dielectric function. The SPR response of a surface covered with particles in 2D aggregates is also analyzed. The experimental SPR curve of the particle aggregates deviates from the theoretical predictions, suggesting dipole interactions between particles.

Original languageEnglish
Pages (from-to)15755-15762
Number of pages8
JournalJournal of Physical Chemistry B
Issue number32
Publication statusPublished - Aug 17 2006
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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