Surface-enhanced Raman and optical scattering in coupled plasmonic nanoclusters

Optical excitation of small Au nanoparticle (NP) clusters of appropriate wavelength is known to generate intense electromagnetic fields localized uniquely at NP junction sites within the nanoclusters. These intense and localized field hot-sites can induce intense surface-enhanced Raman scattering (S...

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Bibliographic Details
Published in:Journal of modern optics 2013-08, Vol.60 (14), p.1107-1114
Main Authors: Tay, Li-Lin, Hulse, John
Format: Article
Language:English
Subjects:
Clusters
Electric fields
Electromagnetism
Gold
gold nanoparticle
Heterogeneity
hot-spot
nanocluster structure
Nanocomposites
Nanomaterials
Nanoparticles
Nanostructure
Optics
plasmonics
Scattering
Simulation
surface-enhanced Raman scattering
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Summary:Optical excitation of small Au nanoparticle (NP) clusters of appropriate wavelength is known to generate intense electromagnetic fields localized uniquely at NP junction sites within the nanoclusters. These intense and localized field hot-sites can induce intense surface-enhanced Raman scattering (SERS) of molecules residing at the junction hot-sites. In this paper, we present a series of electromagnetic simulations, experimental SERS and extinction data obtained from small self-assembled Au NP clusters coated to saturation with a Raman reporter molecule. Our experimental data show that the SERS enhancement factor remains relatively constant despite the heterogeneity of the nanocluster and this is supported by the simulation results. Furthermore, our simulation results show significant variations in the localized electric field intensities of the junction hot-sites in different nanocluster geometries. This explains the observation that increasing the number of hot-sites does not necessarily result in a higher SERS enhancement factor.
ISSN:0950-0340
1362-3044
DOI:10.1080/09500340.2013.821535