Towards Understanding the Impact of Electrochemical Double Layer on the Performance of Graphene Devices

Abstract

The effect of electrochemical double layer (EDL) on the performance of graphene-based sensing platforms has been an area of controversy over the last two decades ¹. The hydrophobic nature of bare graphene tends to repel the water and minimizes the solution/solid surface interactions ². However, the presence of oxygen-based functional groups on graphene introduces negatively charged sites and causes a negative surface zeta potential. Hence, the instant formation of an EDL on a graphene surface in an aqueous solution is inevitable, affecting the graphene surface's chemical/physical interactions ³. Thus far, multiple theories and techniques have been developed to investigate the impact of EDL on graphene sensing performance; however, they either suffer from complexity in design or have ignored the co-existence of other solution parameters such as pH and oxidation-reduction potential ⁴.