Researchers from Sweden demonstrated a simple and mature technology for inkjet printing of high quality few-layer graphene.

The researchers exfoliate graphene from graphite flakes in dimethylformamide (DMF), and then DMF is exchanged by terpineol through distillation (there is a large difference between DMF's and terpineol's boiling points). Terpineol is of much lower volume than DMF and so the graphene is significantly concentrated. Terpineol is also non-toxic and features high-viscosity.

The breakthrough in this research is the development of polymer stabilization that achieves a good ink forumulation which makes it stable. It also does not result in severe flake aggregation (which prevents the dispersions from being practical inks) during solvent evaporation.

The stabilization was achieved by adding a small amount of polymer (ethyl cellulose) before distillation. After printing, the stabilizing polymers can be effectively removed through a simple annealing process.

The researchers fabricated large-area centimeter-scale graphene thin films with between 1 and 6 printing layers on glass slides. This proved that their technology is efficient, low cost and can be used to fabricate a variety of graphene electronic devices with good performance.



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