The Functionalization of Low Dimensional Materials for a Multi-Functional Gas Sensor Platform

Abstract

Presently, most space missions rely on large, heavy, and high-power instrumentation such as mass spectrometers for chemical analysis on planetary bodies. The weight of these payloads is prohibitive to mission cost, and ultimately hinders scientific advancement. This hindrance has driven us to develop a multi-functional gas sensor platform based on the additive manufacturing of low-dimensional materials. The discovery of low-dimensional materials such as graphene and carbon nanotubes (CNTs) has instigated a push to apply these materials in device design. The unique electrical and physical properties of these materials coupled to their high surface area to volume ratio make them outstanding candidates as extremely sensitive gas sensing elements for both chemiresistive and field effect transistor (FET) based devices. The detection of gases using low-dimensional materials as sensing elements relies on change in the resistance of the sensing element associated with electron donation or extraction by the gas to be detected. For most low-dimensional materials, this mechanism is not especially selective. This lack of selectivity necessitates the functionalization of said materials with catalytically appropriate functional units to promote device selectivity while maintaining the high sensitivity of the low-dimensional materials. We will present our efforts on the functionalization of chemiresistive and FET gas sensors using CNTs, graphene and transition metal dichalcogenides with both physical vapor deposition and solution phase approaches. This functionalization will ultimately allow for the fabrication of an array of gas sensors with each sensor demonstrating varied selectivity for the gases of interest. Our functional group choice, process optimization and ultimately sensor performance will be demonstrated.