Nanocarbon Based Chemiresistive Water Quality Sensors

Abstract

Failure to monitor the quality of drinking water can have devastating consequences. The development and implementation of sensing technology can be a crucial aspect of water quality control strategies. Chemiresistive sensors can be installed at any point of the distribution system and can provide real-time data on the levels of different water quality parameters. These sensors work by detecting changes in the conducting properties of a transducing element, induced by interactions with the analyte. Nanocarbon films have attracted interest as possible transducing materials because of their similarities to graphene, a two-dimensional material known for its exceptional electron transport properties. This thesis explores the fabrication and sensing performance of few layer graphene (FLG) and graphene-like carbon (GLC) films. The FLG sensors were used to detect copper ions in water, while the GLC sensors were used to monitor the concentration of free chlorine. The films were functionalized to improve selectivity and showed noticeable changes in their conducting properties as a result of charge transfer between them and the analyte. These changes were quantified by probing the sensors with a constant voltage and they were found to be dependent on the concentration of the analyte over a wide dynamic range. Overall, the work presented in this thesis suggests that, by tuning the selectivity of the films, nanocarbon based chemiresistive sensors can be a universal solution to water quality monitoring.