Synthesis of Graphene on Conducting Substrate by Electrochemical Deposition Method

Abstract

Investigation to optimize the synthesis process of graphene on conducting substrate is essential for many applications. In this investigation suitable approach to extract graphene thin film on a conductive ITO substrate is optimized. This optimization is carried out by electrochemical Reduction of Graphene Oxide (RGO) solution utilizing a repetitive cyclic potential against reference electrode. To do this, Silver chloride reference electrode is employed within a three electrode system at a potential range of (0 to -1.5) V. A number of four consecutive cycles is used to obtain a negative reduction peak. Yet more importantly the material’s electrochemical properties were studied by Cyclic Voltammetry (CV) operation. From CV, it is clear that, the surface area with electrodeposition from ITO to RGO/ITO and RGO/RGO/ITO rates in a potential window of (2V) for (-1 to 1) V is improved. Moreover, Electrochemical Impedance Spectroscopy (EIS) showed reduced electrode surface internal resistance of the modified electrode that dramatic decreased in comparison from 96.33kΩ of RGO/ITO to 32Ω of RGO/RGO/ITO. In addition, Charge/Discharge Cycle (CDC) is obtained that showed relatively symmetrical charging property along with its corresponding discharge equivalents viewing rapid charging/discharging process that favors redox process for increased mobility and thus conductivity improvement. Moreover the modified electrode was studied for its physical characteristics using Scanning Electron Microscopy (SEM) that showed uniform reduced graphene sheets deposition with particles diameter ranging from 1.65µm to 635nm. Atomic Force Microscopy (AFM) was used in contact mode for a square area of 5µm showing increased surface roughness from ITO of 2.773nm in comparison to Reduced Graphene Oxide/RGO/ITO 34.93nm. Results also proved that deposition of multiple layers of Graphene could strongly improve energy storage applications if implemented by allowing the material to hold greater charge in smaller area. This will lead to enhance the power densities far beyond existing electrochemical capacitors in a cost effective eco-friendly manner.