Enhanced SERS stability of R6G molecules with monolayer graphene

In this work, we used monolayer graphene, either underneath or on top of the R6G molecules, to enhance the stability and reproducibility of surface enhanced Raman spectroscopy (SERS). The time evolution of characteristic peaks of the organic molecules was monitored using Raman spectroscopy under continuous light irradiation to quantitatively characterize the photostability. Graphene underneath the organic molecules inhibits the substrate-induced fluctuations; and graphene on top of the organic molecules encapsulates and isolates them from ambient oxygen, greatly enhancing the photostability. Our results showed that the average lifespan of R6G molecules with graphene encapsulation can be increased by about 6-fold under high laser power density (3.67 × 106W/cm2) and is less dependent on the power density of light irradiation.