(Cu2O-Au) – Graphene - Au layered structures as efficient near Infra - Red SERS substrates

Abstract

Near Infra-Red Surface Enhanced Raman Spectroscopy (NIR SERS) has gained huge attention in recent years as the conventional visible SERS suffers from overwhelming fluorescence background from the fluorophore resulting in the masking of Raman signals. In this paper, we propose a novel multilayered SeRS substrate-(cu 2 O-Au)-Graphene-Au-for efficient NIR SERS applications. The proposed structure has a monolayer of Cu 2 O-Au core-shell particles on a Au substrate with 1 nm thick graphene spacer layer. Mie simulations are used to optimize the aspect ratios of core-shell particles to shift their plasmon resonances to NIR region using MieLab software. Further, Finite Difference Time Domain (FDTD) simulations using Lumerical software are used for the design of the multiparticle layered SERS substrate as MieLab software works only for single particle systems. Designed structure is shown to provide high field enhancement factor of the order of 10 8 at an excitation of 1064 nm thus ensuring the possibility of using the proposed structure as efficient NIR SERS substrate which could probably be used for various NIR sensing applications.

Raman spectroscopy for viral diagnostics

“…Other 2D materials, such as graphene, have also been investigated as SERS substrates and indeed the application of unique multi-layered SERS substrate—(Cu2O-Au)-graphene–Au—for effective sensing applications has been suggested in recent literature. These proposed structures have been shown capable of providing high field enhancement (of the order of ~ 10 8 ) at 1064 nm near-IR excitation, which can overcome problems related to visible light-induced fluorescence interference, photo-bleaching, and plasmonic heating, all of which impose limitations on the SERS effect (Nair & Murukeshan 2020 ). The orientation of analyte on the substrate surface also influences the SERS signal and hence has to be controlled by restricting the shape and size of nanoparticles.…”

Fluorescence Resonance Energy Transfer (FRET)-Based ThT Free Sensing of Beta-Amyloid Fibrillation by Carbon Dot-Ag Composites

“…Currently, other technics like biobarcode assays and noble metal surface plasmon resonances are made use in the early detection of ADDL biomarkers 19,[25][26][27] . Surface-enhanced Raman spectroscopy (SERS) using noble metal nanoparticles and layered structures of metal-dielectric composites is another feasible technic for the early stage sensing beta-amyloid fibrillation 28,29 . The development of different technics to inhibit the aggregation of amyloid protein at an earlier stage is equally important as its early detection.…”