GRAPHENE BASED SENSOR FOR NONANAL DETECTION

Abstract

This work delves into the comprehensive understanding of reduced graphene oxide (rGO)-based sensors, specifically focusing on the fabrication of these sensors using soda lime glass as the substrate. Soda lime glass is chosen due to its advantageous properties, including transparency, mechanical strength, and chemical stability, making it a widely used substrate in various applications. This study works on the synthesis, characterization, and application of rGO-coated soda lime glass sensors for the detection of nonanal, which is volatile organic compounds (VOCs) using an electrochemical sensing method. The fabrication process begins with the preparation of reduced graphene oxide. Graphene oxide (GO) is typically synthesized through the Improved Hummers’ method, which involves the oxidation of graphite. This process introduces oxygen-containing functional groups into the graphite structure, rendering it hydrophilic and dispersible in water. Once GO is obtained, it is deposited onto the soda lime glass substrate using solution-based coating techniques: spin coating, dip coating, and drop casting. The coated GO is then reduced to rGO through two different methods: thermal and chemical reduction methods. Each reduction method offers different degrees of oxygen removal and defect restoration, influencing the properties of the resulting rGO. Nonanal is a significant VOC due to its presence in various environments and its impact on air quality and health. The sensing mechanism relies on the electrochemical properties of rGO, which provides a large surface area, high electrical conductivity, and active sites for adsorption. When nonanal molecules come into contact with the rGO-coated sensor, they interact with the surface, causing changes in the resistance of the sensor. These changes are detected and measured using two probe station connected with a source meter.