Screen Printed Conductive Composites with Reduced Graphene Oxide and Silver

This work provides a method to fabricate conductive composites by screen printing of aqueous hybrid inks with graphene oxide (GO) and silver acetate as silver source. The formulation of the aqueous hybrid inks is realized by mixing highly concentrated GO solution and reactive silver solution, which readily results in a formation of viscous pastes. Composite films with four-probe structure were fabricated by means of blade coating, followed by annealing at 160 °C in air and subsequently at 600 °C in Ar/H2. While the reactive silver solution without GO can be completely reduced when annealed at 90 °C in air, resulting in elemental Ag films with resistivity close to the bulk value, no reduction occurs in the hybrid inks under the same annealing condition. Silver nanoparticles are formed from the hybrid inks at 160 °C and discretely distributed on the reduced GOs (rGOs), which shows a retardation effect of GO on the reduction of silver. Further annealing at 600 °C in Ar/H2 leads to partial restoration of sp2 lattice in the rGOs. The resistivity of the composite films increases as the silver content is increased, which is interpreted by using a percolation model with rGO networks.