Hot-Volumes as Uniform and Reproducible SERS-Detection Enhancers in Weakly-Coupled Metallic Nanohelices

• DOI: 10.1038/srep45548
• Publication Date: 2017-03-30T11:10:26Z
• Authors: José M. Caridad; Sinéad Winters; David McCloskey; Georg S. Duesberg; John F. Donegan; Vojislav Krstić
• Keywords: Surface-Enhanced Raman Spectroscopy

Abstract Reproducible and enhanced optical detection of molecules in low concentrations demands simultaneously intense homogeneous electric fields acting as robust signal amplifiers. To generate such sophisticated near-fields, different plasmonic nanostructures were investigated recent years. These, however, exhibit either high enhancement factor ( EF ) or spatial homogeneity but not both. Small interparticle gaps sharp show enormous EFs no near-field homogeneity. Meanwhile, approaches using rounded separated monomers create uniform near-fields with moderate . Here, guided by numerical simulations, we how arrays weakly-coupled Ag nanohelices achieve both strong enhancements, reaching even the limit forreproducible individual molecules. The unique distribution a single nanohelix consists broad hot-spots, merging those from neighbouring specific array configurations generating wide zone (“hot-volume”). We experimentally assessed these via surface-enhanced Raman spectroscopy, obtaining corresponding ~10 7 relative standard deviation <10%. These values demonstrate state-of-the-art substrates for reproducible well compelling related imaging.