Design of Armrest Ag Nanorod Arrays with High SERS Performance for Sensitive Biomolecule Detection

Abstract

To enlarge the surface-enhanced Raman scattering (SERS) enhancement of Ag nanopillar arrays, a well-controlled armrest Ag NRs@Al2O3 structure was designed, aiming at triggering efficient resonance between the nanopillar and the Ag NRs. A series of armrest Ag NRs@Al2O3 with well-designed morphology as well as enhanced “hot spots” quantity by taking advantage of AAO template and oblique angle deposition were successfully fabricated. Both experimental results and numerical simulations revealed localized surface plasmon resonance (LSPR) tunability by simply optimizing the arm length. An optimal substrate with outstanding SERS performance for dyes and biomolecular was realized by enhancing the hot spots area while tuning the resonance peak close to the 785 nm excitation. The as-fabricated 14-Ag NRs@Al2O3 without any surface modification presented a glucose detection limit of 1 × 10–4 mM, endowing our SERS platform for sensitive label-free biodetection.