Researchers from Northwestern University developed a new approach for inkjet printed graphene inks (made from graphene flakes). The new process does not leave any residues on the graphene, and it also produces a graphene ink with a low number of flake-to-flake junctions. This results in highly conductive ink.
The process uses ethanol as a solvent and ethyl cellulose as a stabilizing polymer. The outcome of this is a 15% graphene black powder. The graphene flakes are 50x50 nm2 in size. This powder is then dispersed into a solvent and this creates a fluid ink. The researchers demonstrated inkjet printing - which can be used to make precise patterns, and even multiple-layer structures.