Formulation and Development of Graphene-Based Printable Sensors

The field of printable electronics has been experiencing increased interest and growth to meet the demands of low-cost, flexible, and lightweight devices. From this subset of devices, graphene-based printable sensors are of specific interest due to their transparency, flexibility, biocompatibility, and high conductivity. In this research, a graphene-based ink is formulated and developed with the goal of having it exhibit characteristics that are suitable for a sensor, namely being electrically conductive, easily manufacturable, and printable through an inkjet-based printer. Based on the ink formulation methodologies presented in the journals Carbon and The Journal of Physical Chemistry Letters by Parvez et al. and Secor et al., respectively, a new graphene-based conductive ink formula and process was developed in this project. To develop this ink, a water-based graphene solution was prepared with a sonication process that demonstrated stable graphene suspension and dispersion in deionized water for up to one month. Additionally, the ink was characterized by a statistical sample of particle height and particle lateral size distributions; surface tension; density; viscosity as a function of shear rate; conductivity; and theoretical inkjet printability using a variety of scientific equipment and procedures. The final product was an ink that could be easily manufactured with simple lab equipment and exhibited a desirable set of liquid properties that represent the ability to be theoretically printed but failed to reach an experimental conductivity on the scale that was achieved in the Parvez et al. and Secor et al. studies.