Scientists achieve breakthrough in graphene production

Chemists in Germany have created, for the first time, defect-free graphene from graphite.

Graphene, consisting of a single layer of carbon atoms, has the potential to be used in a wide range of emerging technologies. Graphene’s use in the semi-conductor industry is affected by the size, area and number of defects currently created during synthesis.

Professor Andreas Hirsch, from the University of Erlangen-Nuremberg, said: “This discovery is a breakthrough for experts in the international field of reductive graphene synthesis. Based on this discovery we can expect to see major advancements in terms of the applications of this type of graphene which is produced using wet chemical exfoliation. An example could be cutting defect-free graphene for semi-conductor or sensor technology.”

The team discovered that using benzonitrile during production allows for defect-free graphene to be produced from graphite. This low-cost and efficient process also allows the number of charge carriers — mobile electrons — to be controlled during synthesis, meaning specific electronic properties can be set.

Graphene is commonly produced by chemically exfoliating graphite – a process where metal ions are embedded in graphite, creating an intercalation compound. The stabilised graphene is then separated from the solvent and reoxidised. During this process, defects can occur through the hydration and oxidation of carbon atoms – the addition of benzonitrile prevents this.

The reduced benzonitrile molecule that is formed during the reaction turns red if it doesn’t come into contact with oxygen or water. This allows the number of charge carriers to be determined using absorption measurements, usually this is achieved by measuring voltage.

The research was published in Nature Communications.