Additive Manufacturing of Graphene-Based Devices for Flexible Hybrid Electronics

In this work, I investigate and enhance the fundamental sensing properties of printed electronic nanomaterials (e.g., graphene) in real-world environments while decreasing weight, cost, and power consumption. The dissertation addresses this issue with the following foci in mind: (1) developing a straightforward and repeatable process to synthesize graphene ink which is also compatible with Inkjet-printing (IJP) and Aerosol Jet printing (AJP). (2) Tuning additive manufacturing printing (IJP and AJP) parameters to establish a repeatable manufacturing process and print high performing (graphene-based) electrodes and interconnects, compatible with the underlying substrate. (3) Investigate power dissipation and electrical breakdown in AJP printed graphene interconnects. (4) Investigate the IJP printed graphene electrodes' electrochemical sensitivity with pH and selectivity of Na+ ions and K+ ions. (5) Integrate printed electrochemical sensors with flexible silicon integrated circuits (Flex-ICs) for flexible hybrid electronics applications. Herein we demonstrate printed devices using graphene to enhance capabilities relative to sensitivity, conformability, and fast and repeatable responsivity while reducing the monitoring devices' mass. Understanding the structure-property-processing correlations of our graphene-based devices has helped us improve the consistency, repeatability, and uniformity of the printed systems. This marks a significant step forward for designing flexible hybrid sensors as a platform to fabricate sensors for space, military, and commercial applications.