Quantitative analysis of the defects in CVD grown graphene by plasmon-enhanced Raman scattering

In this paper, a study of quantitative analysis of the defects in chemical vapor deposition (CVD) grown graphene through plasmon-enhanced Raman scattering has been performed. By designing and fabricating three-dimensional hybrid Au nano-particles/single-layer-graphene/Au nano-holes (Au NPs/SLG/Au NHs) structures, the defects induced Raman scattering signals of SLG have been extremely enhanced. The light-graphene interaction between graphene and plasmonic nanostructures heightened the cross-section of the Raman scattering resulting in enhancing Raman signals. In the SERS spectra of graphene, the D band and D′ band which associated with defects-induced double resonance (DR) Raman scattering processes have been clearly observed. A general and empirical formula has been applied to quantify graphene defects nano-crystallite (La) through the relation between the ratio of ID/IG and EL4. Additionally, an empirical formula for quantifying the defects based on the relation between ID’/IG and EL4 was proposed. Besides, the Au NPs/SLG/Au NHs as a SERS substrate has been applied in detecting the fluorescein molecular under low concentration, and it exhibited good SERS performance. The defects-induced signals of graphene are enhanced by SERS, and the empirical formulas are proposed to quantify graphene defects nano-crystallite. [Display omitted]