Fabrication of Flexible Laser Scribed Graphene

Graphene conducts electricity and heat better than anything else and has combination of unique optical and mechanical properties. Electrons have nobilities in graphene over a hundred times those in silicon. Supercapacitors are a category of electrochemical energy storage devices that to some extent have advantages of both batteries and capacitors. In the present work we used a standard optical LightScribe DVD drive to directly do the laser reduction of graphene oxide (GO) films to graphene. GO was prepared by the modified Hummers’ method as reported elsewhere. Briefly, a 2 g graphite powder was added to a mixture of 1 g NaNO3 and 46 ml H2SO4 and the mixture was cooled to 10 °C using an ice bath. In the next step, 6 g KMnO4 was gradually added to the solution and the reaction temperature was maintained below 20 °C. The mixture was then stirred at 35 °C for 2 h. The resulting solution was diluted by adding 92 ml of deionized water until a dark brown suspension was obtained. Then, the solution was treated by adding 340 ml H2O2 solution. Finally, a uniform suspension of GO nanosheets was obtained by adding water to the resulting precipitate and 12 h of sonicating. The resulting suspensions were uniformly drop casted on a LightScribe DVD disk and then dried under the air at an ambient temperature. The GO coated DVD disk was placed in a LightScribe DVD drive with a wavelength of 780 nm and a spot size of 20 µm. The reduced composite was peeled off from the DVD disk and was glued to the polyethylene terephthalate (PET) substrate. The prepared electrodes were attached to copper wire using silver paste and the exposed areas of silver paste to electrolyte were passivated. An R129348 Bruker Equinox 55 Fra 106/s spectrometer was used for Raman spectroscopy. The surface of electrodes was observed by FESEM (HITACHI S-4160). Cyclic voltammetry (CV) and galvanostatic charge/discharge (CD) techniques were employed to characterize the performance of LSG as a promising candidate for electrode materials for supercapacitors