Graphene is the most fascinating material due to its exceptional electrical and mechanical properties. The reduced form of graphene oxide (GO) is best suitable for sensor applications. There are numerous methods available for reducing GO by synthetic reducing agents that are not environment-friendly and cost-effective. Therefore, in this research work, natural lemon juice is used as a potential reducing agent. It creates defects on the GO surface by altering various functional groups. These are clearly visible in Raman and FTIR results and help in the sensing of the lead (Pb2+) and cadmium (Cd2+) ions. Field effect transistor (FET) based active structure is used to amplify its sensitivity and discriminate the lead and cadmium ions by tuning the gate voltage. The optimized gate voltages for lead (Pb2+) and cadmium (Cd2+) ions are -1.6 V and 0.8 V, respectively, at which the sensor shows the maximum response. This green synthesis approach of sensor fabrication highlights sustainable and cost-effective solutions in the field of reduced graphene-based FET sensors.
