Millimeter-long multilayer graphene nanoribbons prepared by wet chemical processing

Millimeter long multilayer graphene nanoribbons were prepared by a chemical treatment of graphite oxide (GO). To our knowledge, this is the very first report to harvest ultralong graphene ribbons with length dimension >1 mm using a wet chemical process. Scanning electron microscope (SEM) images reveal the nanoribbon length larger than 1 mm and width similar to 10 mu m. X-ray photoelectron spectroscopy (XPS) analysis shows that oxygen-containing functional groups decreased as the extent of the chemical treatment increased. X-ray diffraction (XRD) and Raman spectroscopy studies confirmed the XPS result and unveil more graphitic sheet like structure formed as GO was reduced by more concentrated NaOH. It is found that by adjusting NaOH/GO mass ratio during the chemical treatment, we can produce >1 mm long multilayer graphene nanoribbons and achieve controllable degree of reduction to the GO material. It is expected that this technique will make ultralong graphene nanoribbons readily available for research and applications. (C) 2014 Elsevier Ltd. All rights reserved.