Characterization of GO, rGO, and PEI Doped Graphene Nanocomposites for Biosensor Applications

Thin films of two graphene derivatives, graphene oxide (GO) and reduced graphene oxide (rGO) undoped and doped with electron rich polymer, polyethyleneimine (PEI) were made using a glass substrate coated with indium tin oxide (ITO). In this chapter, the effects of PEI doped GO and rGO were investigated. The films were deposited by using solution deposition technique, electrochemical deposition. PEI doping enhances the conductivity of the films as found from cyclic voltammetry (CV) test and electrochemical impedance spectroscopy (EIS) measurement. Scanning electron microscopy (SEM) result shows uniform structure of the deposited films. FTIR, Raman effect, and XRD test shows the as-synthesized powder characteristics. The CV analysis of PEI doped rGO demonstrated the high surface area and high specific capacitance of 40 F/g at a scan rate of 100 mV/s. Also, the EIS analysis of PEI doped rGO showed the lowest equivalent series resistance (−5 Ω) and charge transfer resistance (12.8 Ω) due to the PEI doping. These PEI doped graphene nanocomposites based films can be used as transduction layer as well as sensing layer for biosensor applications, such as clinical diagnostics, agriculture, food industries, and environmental monitoring.