Raman signatures of SLG dispersed in degassed water (‘‘eau de graphene’’)

We study the intrinsic Raman signatures of single layer graphene (SLG) dispersed in degassed water without additives, so called ‘‘eau de graphene” (EdG) and compare them to those of suspended SLG. The Raman signatures of SLG superimpose to those of water. The most characteristic signature of SLG in EdG is a narrow and symmetric 2D band with a width depending on processing conditions. The position of the G and 2D bands indicate moderate biaxial compressive strain and weak n doping. The intensity of the D band and the width of the G band are discussed in terms of point-defect density and flake size. We show that point defects can be easily cured by preparing thin films from EdG and annealing at 800°C