▎ 摘　　要

In this work, a single-layer of graphene oxide (GO), reduced graphene oxide (r-GO), and graphene quantum dot (GQD) nanosheets were synthesized using a modified Hummers' method. AFM and FTIR spectroscopies were used to confirm single-layer graphene synthesis and proper reduction process. Photoluminescence (PL) and Z-scan characterizations showed a high existence of linear and non-linear optical properties in these nanomaterials. PL spectra of r-GO showed a peak at 665 nm, but an appeared blueshift in the PL spectrum of GO (600 nm) and GQD (500 nm) nanosheets indicate a bandgap opening in their band structures. According to Raman results, the I (D)/I(G) intensity ratio of GO is bigger than r-GO, which can be assigned to higher linear optical properties of GO than r-GO and higher non-linear optical properties of r-GO than GO. Finally, our results demonstrated that edges length and functional groups on the edges define the appearance of linear and non-linear optical properties in graphene-based nanomaterials, and these properties can be manipulatable in terms of oxidation/reduction level, surface area size and edge length.