One-pot in situ photochemical synthesis of graphene oxide/gold nanorod nanocomposites for surface-enhanced Raman spectroscopy

Abstract

Nanoscale engineered plasmonic materials that can efficiently sustain surface enhanced Raman scattering (SERS) have been strongly pursued for high sensitivity molecular detection. In this work, we report the production of gold nanorod/graphene oxide (GNR/GO) nanocomposites by a simple, one-pot process whereby GNR are formed directly onto the GO flakes in solution by UV light irradiation. The proposed method is easily scalable and results in GNRs with low dispersion in size and aspect ratio of ∼3. The GNR/GO hybrids were deposited in glass by filtration yielding homogenous films that were systematically tested as SERS active substrates. Raman spectroscopy mapping revealed that the tested substrates present spatially homogenous and reproducible SERS responses. Analysis of Raman spectroscopy by using a model molecule (cresyl violet perchlorate) indicates that the produced substrates can provide very large SERS enhancement factors (∼10⁶) and very low molecular detection limits (10⁻¹¹ M).