Water dispersible functionalized graphene fluoride with significant nonlinear optical response

Graphene fluoride (G.F.) is the youngest in the family of graphene derivatives. Being optically transparent in the visible spectrum, G.F. is unique among other low dimensional carbon materials. In this work, colloidal dispersions are prepared by aqueous-phase exfoliation of graphite fluoride through non-covalent functionalization with perfluorooctanoate units. Light scattering and electrophoresis reveal the exceptional stability of the dispersion, while the formation of ultrathin G.F. sheets is verified by electron and atomic force microscopy. In addition, for the first time it is reported that G.F. colloids exhibit high third-order nonlinear optical response, suggesting their potential application in photonic and opto-electronic devices.