Researchers cut cost of graphene production

November 19, 2015 // By Graham Prophet
A group of researchers led by Dr Ravinder Dahiya at the University of Glasgow, Scotland, has found a way to produce large sheets of graphene, borrowing materials from the manufacture of lithium-ion batteries. The cost of this substrate, which directly relates to the cost-of-production of the graphene itself, is around 1/100th of the material previously used.

Graphene has been hailed as a 'wonder material' since it was first isolated from graphite in 2004. Graphene is just a single atom thick but it is flexible, stronger than steel, and capable of efficiently conducting heat and electricity.

However, widespread industrial adoption of graphene has so far been limited by the expense of producing it. Affordable graphene production could lead to a wide range of new technologies reaching the market, including synthetic skin capable of providing sensory feedback to people with limb prostheses.

In a new paper published in the journal Scientific Reports , the researchers outline their process. Graphene is often produced by chemical vapour deposition, CVD, (a process familiar in semiconductor manufacturing) in which gaseous reactants deposit into a film of the desired product on a substrate.

Prior work has used copper that, at a microscopic scale, has surface scratches and defects caused by the rolling process that produces it. The research team instead turned to a copper foil – commercially available ultra-smooth Cu foil by Mitsui Mining and Smelting – that is volume-manufactured for use as the negative electrodes in lithium-ion batteries. The ultra-smooth surface of the copper provided an excellent bed for the graphene to form upon.

They found that the graphene they produced offered a marked improvement in the electrical and optical performance of transistors which they made compared to similar materials produced from the older process; among other improvements, the graphene covered the substrate more completely, and was better-structured with fewer defects in the film.

Dr Dahiya, of the University of Glasgow’s School of Engineering, said: ““The commercially-available copper we used in our process retails for around one dollar per square metre, compared to around $115 for a similar amount of the copper currently used in graphene production. This more expensive form of copper often required preparation before it can be used, adding further to the cost of the process.

“Our process produces