Preparation and optical properties of sonication-assisted nitrogen doped graphene oxide sheets

The graphene and graphene oxide sheets were prepared from directly exfoliated and Hummer's method. Nitrogen doping was applied with the assistance of ultrasonicator to achieve doping via a simple, low-cost aqueous route. The size of graphene and graphene oxide sheets was examined by transmission electron microscopy with a size of several micrometer. The doping phenomenon was achieved by the addition of aqua ammonia and the analysis were examined by Raman microscopy. The approve of N-doping was got with the appearance of G' band. The existence of nitrogen element were further examined by energy dispersive spectroscopy.