Self-assembly of mildly reduced graphene oxide monolayer for enhanced Raman scattering.

Graphene-enhanced Raman scattering (GERS) has attracted much attention recently. In present study, monolayer of chemically reduced graphene oxide (RGO) nanosheets was chemically bonded on Si substrates and their possible applications in Raman scattering were investigated. In comparison with the mechanically exfoliated graphene, mildly reduced graphene oxide (MR-GO) monolayer is a better substrate to quench the fluorescence (FL) signals and simultaneously enhance the Raman signals of adsorbed Rhodamin 6G (R6G) molecules. Raman and X-ray photoelectron spectra indicate that π–π stacking and the residual polarized oxygen groups on MRGO surface, which can produce a strong local electric field under laser excitation, are mainly responsible for the excellent GERS effect of MR-GO substrate, while the charge transfer between R6G and MR-GO has a relatively low contribution for GERS effect. Our results not only provide a new approach to realize sensitive GERS substrate, but also are helpful for improving the fundamental understanding of GERS effect on RGO substrate. [ABSTRACT FROM AUTHOR]