2-D Material Sensors on the Electronic Nose for the Sensitive Detection of VOCs

Citation

Lee, Kyra SoHyun (2021) 2-D Material Sensors on the Electronic Nose for the Sensitive Detection of VOCs. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/j5e1-k535. https://resolver.caltech.edu/CaltechTHESIS:09202020-194859590

Abstract

Chapter 1

When coated with a polymer surface layer and suspended on 3-D textured glass electrodes, the hybrid combination of polymer and graphene yields sensitive chemiresistive vapor sensors. The expansion and contraction of the polymer layer when it absorbs/reacts with the VOCs, is proposed to produce tremendous train on the suspended graphene. Hence, when VOCs permeates into the polymer layer, sizable electrical resistive changes as folds and creases is induced in the graphene due to its high gauge factor. The hybrid suspended polymer/Gr sensor exhibits substantial responses to polar organic vapors, especially pyridine, while also exhibiting reversibility and the potential future tunability in the types of polymers used as the reactive surface layer.

Chapter 2

Various polar and non-polar functional groups were covalently bonded onto MoS2 yielding incredibly sensitive chemiresistive vapor sensors. The VOCs' interaction to the functional end groups produced tremendous signal, while also exhibiting reproducibility and reversibility. Future work will further standardize the sensors while also exploring tunability in the types of groups used.

Chapter 3

This chapter reflects the very start of my PhD research, and one of the important lessons to learn about the electronic nose. It is an example that I wish my predecessors taught me (all had graduated by the time I began my research) that I hope to pass onto future nose users. It is just one example of many projects that had similar end result. Many key lessons can be learned for future nose users. Readers can choose to skip reading this.

Thesis Files