Graphene's dazzling properties promise a technological revolution, but Europe may have to spend a billion euros to overcome some fundamental problems.
Graphene offers a way to make flexible and transparent smartphone screens.
BYUNG HEE HONG
Mr G gazes out from a recruitment poster hanging in an engineering building in Cambridge, UK. His cartoon cape billows out behind him, his sketched-in muscles ripple beneath his costume, his chest is emblazoned with a 'G' inside a hexagon — and his forefinger points straight at the viewer. “I want you for the Graphene Flagship!” declares the cartoon crusader, championing a material as super as he is.
Graphene is the thinnest substance ever made: a single sheet of carbon atoms arranged in a hexagonal honeycomb pattern. It is as stiff as diamond and hundreds of times stronger than steel — yet at the same time is extremely flexible, even stretchable. It conducts electricity faster at room temperature than any other known material, and it can convert light of any wavelength into a current. In the decade since graphene was first isolated, researchers have proposed dozens of potential applications, from faster computer chips and flexible touchscreens to hyper-efficient solar cells and desalination membranes
Hence Mr G's call to arms. The character was created in 2011 to help publicize a multinational push for a Graphene Flagship project: a decade-long, €1-billion (US$1.35-billion), all-European effort to take graphene from the laboratory bench to the factory floor
Most research laboratories still make graphene using the method pioneered in 2004 by Andre Geim and Konstantin Novoselov at the University of Manchester, UK, who went on to win the 2010 Nobel Prize in Physics for their studies. Geim and Novoselov found that they just had to touch a strip of household sticky tape to ordinary graphite — which consists of billions of layers of graphene stacked on top of one another — and they could peel off thin flakes of carbon. By repeatedly splitting those flakes, they were eventually left with graphene2. This was a technique that any laboratory could use, and graphene research exploded.
But the method is much too slow and finicky for industrial-scale production. Just one micrometre-sized flake made in this way can cost more than $1,000 — making it, gram for gram, one of the most expensive materials on Earth.
The leading alternative3 relies on chemical vapour deposition (CVD), whereby methane is piped over a catalytic copper foil heated to about 1,000 °C. As the methane breaks down, small islands of pure carbon begin to grow on the foil, linking together to form a patchwork polycrystalline sheet of graphene. Harsh chemicals are then used to etch away the copper to free a sheet of graphene tens of centimetres wide, which can be transferred to a silica or polymer substrate. That process brings costs below $100,000 per square metre, but the product is often riddled with defects, impairing its electrical properties and making it much weaker than flakes produced by the sticky-tape method.
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