T. Mather, R. Mehta, S. Bastos, A.B. Kaul
University of North Texas,
United States
Keywords: inkjet-printed graphene, solution processing, gas sensing, physisorption
Summary:
Gas sensors are prominent devices that provide unparalleled safety to industry workers and emissions data to environmental agencies via signaling through resistive, calorimetric, optical, and many more types of measurement. Conventional gas sensors consist of metal-oxide devices such as TiO2, ZnO, and SnO2 which operate at higher temperatures and have poor selectivity when in the presence of heightened moisture. In comparison with a common two-dimensional (2D) material like graphene, a 2D material-based gas sensor can operate effectively at room temperature, has a large number of active sites naturally attributed to a high surface-to-volume ratio, and can be easily fabricated from commonly used chemical exfoliation methods. Due to the highly porous nature of solution-processed graphene, especially when spin-coated or printed onto a substrate, the material has a natural affinity for molecular adsorption of many gases. In this study, we conduct electrical transport measurements over time for a two-terminal inkjet-printed graphene device to study how the transport varies upon exposure of the device to various incoming gasses, which is interesting to examine for gases that do not necessarily readily react with graphene. The cyclical behavior of the device was examined when exposed to nitrogen and carbon dioxide at various flow rates and bias power levels. Material characterization was conducted using scanning electron microscopy (SEM) imaging and atomic force microscopy (AFM) to examine the surface morphology of our device to confirm its accommodating porous structure. The preliminary data presented in this study suggests that graphene is well suited for gas-sensing applications involving semi-reactive gasses and sensor applications in the future.