Hot volumes for highly enhanced and reproducible SERS detection in weakly-coupled metallic nanohelices
Caridad JM, Winters S, McCloskey D, Duesberg GS, Donegan JF, Krstic V (2017)
Publication Language: English
Publication Type: Journal article, Letter
Publication year: 2017
Journal
Book Volume: 7
Article Number: 45548
DOI: 10.1038/srep45548
Open Access Link: https://www.nature.com/articles/srep45548
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 ~107 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.
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Ireland (IE)How to cite
APA:
Caridad, J.M., Winters, S., McCloskey, D., Duesberg, G.S., Donegan, J.F., & Krstic, V. (2017). Hot volumes for highly enhanced and reproducible SERS detection in weakly-coupled metallic nanohelices. Scientific Reports, 7. https://doi.org/10.1038/srep45548
MLA:
Caridad, Jose M., et al. "Hot volumes for highly enhanced and reproducible SERS detection in weakly-coupled metallic nanohelices." Scientific Reports 7 (2017).
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