open access publication

Article, 2023

Lithography-free fabrication of scalable 3D nanopillars as ultrasensitive SERS substrates

Applied Materials Today, ISSN 2352-9415, 2352-9407, Volume 31, Page 101763, 10.1016/j.apmt.2023.101763

Contributors

Chirumamilla, Anisha (Corresponding author) [1] Moise, Ioana-Malina 0000-0003-2513-3638 [1] Cai, Ziru [2] Ding, Fei 0000-0001-7362-519X [2] Jensen, Karina B. [1] Wang, Deyong [1] Kristensen, Peter Kjær 0000-0001-7260-0548 [1] Jensen, Lars Rosgaard 0000-0003-1617-0306 [1] Fojan, Peter 0000-0002-0626-4766 [1] Popok, Vladimir N 0000-0002-9480-3765 [1] Chirumamilla, Manohar 0000-0002-6812-286X (Corresponding author) [1] Pedersen, Kjeld 0000-0002-6835-1566 [1]

Affiliations

  1. [1] Aalborg University
    2. [NORA names: AAU Aalborg University; University; Denmark; Europe, EU; Nordic; OECD];
  2. [2] University of Southern Denmark
    3. [NORA names: SDU University of Southern Denmark; University; Denmark; Europe, EU; Nordic; OECD]

Abstract

Surface-enhanced Raman spectroscopy (SERS) detection of analyte molecules at ultra-low concentrations requires highly-efficient plasmonic nanostructures enabling a high hot-spot density. However, a facile and cost-effective strategy toward large-area fabrication of efficient nanostructures with significant electromagnetic field enhancement remains a great challenge. Further, SERS faces reliability issues with the molecular fingerprint at ultra-low concentrations. This work shows a one-step rapid fabrication technique utilizing glancing angle deposition for growing 3D nanopillars of Ag or Au, which is facile, scalable and cost-effective. The 3D nanopillar substrates can reliably detect analyte molecules with concentrations as low as 10-18 M with a high signal-to-noise ratio molecular fingerprint proven for Cresyl violet, p-aminothiophenol and Rhodamine 6G. The ultra-high enhancement is realized in conjunction with the formation of a high hot-spot density due to localized surface plasmons and surface plasmons at metal/air interface. A portable handheld Raman spectrometer is used to evaluate the potential application of the nanopillars for on-site diagnostics. It avoids the need for sophisticated tabletop instruments yet provides high-precision molecular specificity outside specialized laboratories. The 3D nanopillar substrates show excellent molecular detection limits at 10−15 M concentrations when tested with a handheld Raman spectrometer. The uniqueness of the 3D nanopillar features with the formation of a high density of hot-spots and one-step nanofabrication methods provide a platform to unravel on-site diagnostics with cost-effective approaches.

Keywords

Au, Raman spectrometer, Raman spectroscopy, SERS substrates, analyte molecules, angle deposition, applications, approach, concentration, conjunction, cost-effective, cost-effective approach, cost-effective strategy, cresyl, cresyl violet, density, density of hot spots, deposition, detect analyte molecules, detection, detection limit, detection of analyte molecules, diagnostics, efficient nanostructures, electromagnetic field enhancement, enhancement, fabrication, fabrication techniques, features, field enhancement, fingerprint, formation, glancing angle deposition, handheld, handheld Raman spectrometer, hot spot density, hot spots, instrument, interface, issues, laboratory, large-area fabrication, limitations, lithography-free fabrication, localized surface plasmons, metal/air interface, molecular detection limits, molecular fingerprints, molecular specificity, molecules, nanopillar substrate, nanopillars, nanostructures, on-site diagnostics, p-aminothiophenol, plasmon, plasmonic nanostructures, portable handheld Raman spectrometer, potential applications, reliability issues, rhodamine, rhodamine 6G, specialized laboratories, specificity, spectrometer, spectroscopy, strategies, substrate, surface, surface plasmons, surface-enhanced Raman spectroscopy, technique, ultra-high enhancement, ultra-low concentrations, ultrasensitive SERS substrate, uniqueness, violet

Funders

  • Novo Nordisk Foundation
  • Novo Nordisk (Denmark)

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