Chemical exfoliation of pure graphene sheets from synthesized ZnO–graphene quasi core–shell quantum dots

We report on a novel, simple and easy method to produce graphene layers using chemically synthesized ZnO–graphene quasi core–shell quantum dots. Initially, graphite powder was partially oxidized by acid treatment of graphite powder, which was then mixed with zinc acetate dihydrate in a dimethyl formamide solution. During this process, graphene sheets were detached from the graphite oxide layers through a layer-by-layer chemical peel-off and then partially covered from ZnO quantum dots which formed in the dimethyl formamide solution. Therefore, the ZnO–graphene quantum dots were dissolved in hydrochloric acid solution and then pure graphene layers were extracted from solution. The structural, optical, and electrical properties of obtained graphene layers were analyzed by using X-ray diffraction, transmission electron microscope, Raman spectroscopy, X-ray photoemission spectroscopy instrument.