Molecule bridged graphene/Ag for highly conductive ink

Abstract

Printing is a method of additive manufacturing that can reduce material costs and environmental contamination during the fabrication process. Ag ink is commonly used in printed electronics, such as interconnects, inductors, and antennas. However, the high cost of noble Ag restricts its massive applications. To reduce the cost of the state-of-the-art Ag ink and realize large-scale manufacturing, we develop a molecule-bridged graphene/Ag (MB-G/A) composite to produce highly conductive and cost-effective paper-based electronics. Graphene can be used to substitute part of Ag nanoparticles to reduce costs, form a conducive percolation network, and retain a reasonable level of conductivity. We adopt cysteamine as a molecular linker, because it anchors on the surface of graphene via the diazonium reaction. Additionally, the thiol functional group on the other end of cysteamine can bond to a Ag atom, forming a molecular bridge between graphene and Ag and promoting electron transport between Ag and graphene. As a result, the maximum conductivity of MB-G/A inks can reach 2.0 × 105 S m−1, enabling their successful application in various printable electronics. In addition, the optimum MB-G/A ink costs less than half as much as pure Ag inks, showing the great potential of MB-G/A ink in commercial electronic devices.