Plasmonic nanogap-enhanced raman scattering using a resonant nanodome array

Hsin Yu Wu, Charles J. Choi, Brian T. Cunningham

Research output: Contribution to journalArticlepeer-review

109 Citations (Scopus)

Abstract

The optical properties and surface-enhanced Raman scattering (SERS) of plasmonic nanodome array (PNA) substrates in air and aqueous solution are investigated. PNA substrates are inexpensively and uniformly fabricated with a hot spot density of 6.25 × 106 mm-2 using a large-area nanoreplica moulding technique on a flexible plastic substrate. Both experimental measurement and numerical simulation results show that PNAs exhibit a radiative localized surface plasmon resonance (LSPR) due to dipolar coupling between neighboring nanodomes and a non-radiative surface plasmon resonance (SPR) resulting from the periodic array structure. The high spatial localization of electromagnetic field within the ∼10 nm nanogap together with the spectral alignment between the LSPR and excited and scattered light results in a reliable and reproducible spatially averaged SERS enhancement factor (EF) of 8.51 × 107 for Au-coated PNAs. The SERS enhancement is sufficient for a wide variety of biological and chemical sensing applications, including detection of common metabolites at physiologically relevant concentrations. Surface-enhanced Raman scattering (SERS) sensors are integrated in a flow cell for in-line, real-time monitoring and detection of a urinary metabolite. The effect of highly confined electromagnetic fields associated with the localized surface plasmon resonance on the analyte molecules present at EM hot spots results in enhanced excitation of Raman vibrational modes and thus in a substantial increase in the SERS intensity.

Original languageEnglish
Pages (from-to)2878-2885
Number of pages8
JournalSmall
Volume8
Issue number18
DOIs
Publication statusPublished - Sep 24 2012
Externally publishedYes

Keywords

  • biosensors
  • nanodome arrays
  • nanostructures
  • plasmonics
  • surface-enhanced raman spectroscopy

ASJC Scopus subject areas

  • Biomaterials
  • Engineering (miscellaneous)
  • Biotechnology

Fingerprint Dive into the research topics of 'Plasmonic nanogap-enhanced raman scattering using a resonant nanodome array'. Together they form a unique fingerprint.

Cite this