Numerical investigation of the plasmonic properties of bare and cysteine-functionalized silver nanoparticles

Anikó Szalai, Áron Sipos, Edit Csapó, Viktória Hornok, Lszló Tóth, Mária Csete, Imre Dékány

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)

Abstract

The absorption spectra of different aqueous dispersions containing silver nanoparticles were computed by finite element method and compared to spectra determined by UV-Visible spectroscopy. This comparative study proved that the spectrum measured on the aqueous dispersion of bare silver nanoparticles with absorptance maximum at λmeas = 391 nm corresponds to the characteristic UV surface plasmon band of spherical nanoparticles with 8.25 nm diameter. The presence of aggregates in aqueous dispersions resulted in splitting on the spectrum, when the surface of the silver nanoparticles with cAg = 2×10-4 M concentration was functionalized by L-cysteine with cCys=5.7×10-6 M concentration. The simplest aggregate-geometries that exhibit resonance at the measured absorptance maxima were determined by varying the number of silver nanoparticles, and the inter-particle distance in linear chains, and taking 0.45 nm thick cysteine-shell into account. The FEM computations proved that the primary maxima in the UV involve quadrupolar modes, while the secondary maxima red-shifted to λ meas-2=567 nm at pH=2.98 and λ meas-2'=588 nm at pH=4.92 originate from coupled dipolar plasmon resonances on extended aggregates aligned along the E-field oscillation direction. The non-aggregated particles and the aggregates rotated with respect to the E-field oscillation direction significantly contribute to the UV peak.

Original languageEnglish
Title of host publicationPlasmonics
Subtitle of host publicationMetallic Nanostructures and Their Optical Properties IX
DOIs
Publication statusPublished - Oct 19 2011
EventPlasmonics: Metallic Nanostructures and Their Optical Properties IX - San Diego, CA, United States
Duration: Aug 21 2011Aug 25 2011

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume8096
ISSN (Print)0277-786X

Other

OtherPlasmonics: Metallic Nanostructures and Their Optical Properties IX
CountryUnited States
CitySan Diego, CA
Period8/21/118/25/11

Keywords

  • Aggregates
  • Collective resonances
  • Dipolar modes
  • LSPR biosensor
  • Nanoparticles
  • Quadrupolar modes
  • pH dependence

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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  • Cite this

    Szalai, A., Sipos, Á., Csapó, E., Hornok, V., Tóth, L., Csete, M., & Dékány, I. (2011). Numerical investigation of the plasmonic properties of bare and cysteine-functionalized silver nanoparticles. In Plasmonics: Metallic Nanostructures and Their Optical Properties IX [80963B] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 8096). https://doi.org/10.1117/12.894015