Gold on graphene as a substrate for surface enhanced Raman scattering study

TL;DR

This study demonstrates that a 7 nm gold film on single-layer graphene serves as an effective SERS substrate, enhancing Raman signals while suppressing background fluorescence, useful for detecting low concentration molecules.

Contribution

The paper introduces a novel SERS substrate combining gold films and graphene, optimizing signal enhancement and background suppression for molecular detection.

Findings

7 nm gold film on graphene yields strongest SERS signals

Graphene quenches photoluminescence from gold and molecules

Enhanced detection of low concentration molecules

Abstract

In this paper, we report our study on gold (Au) films with different thicknesses deposited on single layer graphene (SLG) as surface enhanced Raman scattering (SERS) substrates for the characterization of rhodamine (R6G) molecules. We find that an Au film with a thickness of ~7 nm deposited on SLG is an ideal substrate for SERS, giving the strongest Raman signals for the molecules and the weakest photoluminescence (PL) background. While Au films effectively enhance both the Raman and PL signals of molecules, SLG effectively quenches the PL signals from the Au film and molecules. The former is due to the electromagnetic mechanism involved while the latter is due to the strong resonance energy transfer from Au to SLG. Hence, the combination of Au films and SLG can be widely used in the characterization of low concentration molecules with relatively weak Raman signals.