Laser scribing for simultaneous nitrogen doping and reduction of graphene oxide films for flexible high energy/power density supercapacitors

Major research efforts have been aimed at replacing traditional fossil fuels with green energy sources to meet the current energy crisis and environmental concerns. In this work, a low cost, fast processing technique is proposed for simultaneous doping, reduction and patterning of graphene oxide films supported on flexible poly-(ethylene terephthalate) PET substrate. Both reduced graphene oxide (rGO), and nitrogen doped reduced GO (N-rGO) films are successfully synthesized from GO dispersion in one single step using laser scribing technique. The rGO, and N-rGO films are examined as electrodes for supercapacitor (SC) application. The aim of this work is to develop, lightweight, thin, flexible, and environmentally friendly supercapacitor with potential for application in wearable electronics and flexible displays, using a simple technique. The films are found to depict high electrical conductivity of 325, and 1539 Sm⁻¹ for rGO, and N-rGO respectively. The performance of the assembled N-rGO based SC is compared to the undoped based SC. The electrochemical performance is estimated by means of cyclic voltammetry (CV), Galvanic constant current charge-discharge (GCCD) and electrochemical impedance spectroscopy (EIS) measurements via two electrodes configuration. The fabricated rGO, and N-rGO devices exhibit specific capacitance of 344, and 2995 mFg⁻¹, respectively at a current of 0.2 mA. Nitrogen doping is found to have positive effect on the behaviour of SC. N-rGO based SC reveals high energy and power densities. The prepared films represent a potential material for flexible high-performance supercapacitors. Moreover, the devised technique represents a convenient method for large scale fabrication of flexible functionalized graphene films.