Hot-Volumes as Uniform and Reproducible SERS-Detection Enhancers in Weakly-Coupled Metallic Nanohelices
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2017Access:
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Caridad, J.M. and Winters, S. and McCloskey, D. and Duesberg, G.S. and Donegan, J.F. and KrstiÄ , V., Hot-Volumes as Uniform and Reproducible SERS-Detection Enhancers in Weakly-Coupled Metallic Nanohelices, Scientific Reports, 7, 45548, 2017Download Item:
Abstract:
Reproducible and enhanced optical detection of molecules in low concentrations demands
simultaneously intense and homogeneous electric fields acting as robust signal amplifiers. To generate
such sophisticated optical near-fields, different plasmonic nanostructures were investigated in
recent years. These, however, exhibit either high enhancement factor (
EF
) or spatial homogeneity
but not both. Small interparticle gaps or sharp nanostructures show enormous
EFs
but no near-field
homogeneity. Meanwhile, approaches using rounded and separated monomers create uniform near-
fields with moderate
EFs
. Here, guided by numerical simulations, we show how arrays of weakly-
coupled Ag nanohelices achieve both homogeneous and strong near-field enhancements, reaching
even the limit forreproducible detection of individual molecules. The unique near-field distribution of
a single nanohelix consists of broad hot-spots, merging with those from neighbouring nanohelices in
specific array configurations and generating a wide and uniform detection zone (“hot-volume”). We
experimentally assessed these nanostructures via surface-enhanced Raman spectroscopy, obtaining
a corresponding
EF
of ~10
7
and a relative standard deviation
<
10%. These values demonstrate arrays
of nanohelices as state-of-the-art substrates for reproducible optical detection as well as compelling
nanostructures for related fields such as near-field imaging.
Author's Homepage:
http://people.tcd.ie/krsticvhttp://people.tcd.ie/dmcclosk
http://people.tcd.ie/jdonegan
http://people.tcd.ie/duesberg
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PUBLISHEDcited By 1
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Scientific Reports7
45548
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Full text availableKeywords:
plasmonic nanostructuresDOI:
http://dx.doi.org/10.1038/srep45548Metadata
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