Carbon Based Materials for Electrochemical Bio Sensing and Energy Storage Devices

Abstract

Electrochemical sensors play a crucial role in various fields due to their ability to detect and quantify chemical compounds or biological molecules based on their electrochemical properties. Electrochemical sensors are generally applied for their advantageous properties such as high sensitivity, high selectivity, rapid response rate, and cost effectiveness. They can be easily developed in a lab on chip-based (LOC) sensing and developing onsite-based sensors. This versatility makes them valuable across diverse fields, including environmental monitoring, healthcare, the food and beverage industry, and security. Miniaturization enables integration into wearable devices, smartphones, and other portable platforms, facilitating decentralized testing and continuous monitoring. This thesis deals with the onsite electrochemical sensors for the detection of paraquat which is highly toxic among most of the herbicides along with its non-biodegradable nature. Most of the sensing was carried out using pristine materials as they are highly reproducible, and have better baseline performance, high stability, and high sensitivity. A novel surface treatment method has been employed on laser induced graphene (LIG) for highly sensitive detection of paraquat. Such surface treatment has shown a significant amount of increase in the current profile in cyclic voltammetry. The contact angle was also reduced allowing the aqueous medium to meddle into the 3D porous structure allowing sensitive detection of PQ. LIG is one of the potential materials due to its robust production and flexibility in nature. Materials such as boron doped diamond (BDD) and boron doped carbon nano walls (B:CNWs) have been compared for the electrochemical sensing of paraquat with B:CNWs showing superior peak current profile along with a better limit of detection (LOD) than BDD. Since BDD has a much stable surface phenomenon composite based system was also investigated for electrochemical sensing. A novel composite system was developed for electrochemical sensing.