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Chemistry: The trials of new carbon

Researchers have spent 25 years exploring the remarkable properties of fullerenes, carbon nanotubes and graphene. But commercializing them is neither quick nor easy.

In fairy tales, third place is often the best: it's usually the third casket that contains the treasure, and the third child who finds fame and fortune. And so it may be for graphene, the third and most recently discovered form of 'new carbon'. The football-shaped fullerenes¹, discovered in 1985, and the hollow cylindrical carbon nanotubes², first characterized in 1991, have so far had a limited impact on industry. But now graphene, a one-atom-thick flat sheet of carbon, seems to be surrounded by favourable omens — not the least of which is the speed with which groundbreaking experiments on its properties were rewarded with the 2010 Nobel Prize in Physics.

It has been just six years since Nobel laureates Andre Geim and Kostya Novoselov at the University of Manchester, UK, first reported using sticky tape to peel atomically thin layers of graphene from lumps of graphite³. But the material — essentially just an unrolled nanotube — has turned out to have properties just shy of miraculous: a single layer of graphene is simultaneously the world's thinnest, strongest and stiffest material, as well as being an excellent conductor of both heat and electricity.

Graphene has been showered with media attention as companies vie to bring those attributes to market. Last year, graphene was the subject of around 3,000 research papers and more than 400 patent applications. South Korea is planning a US$300-million investment to commercialize the material, and companies ranging from IBM to Samsung are testing graphene electronics — ultra-small, ultra-fast devices that might one day replace the silicon chip. The hype over graphene has reached such a pitch that a casual follower might wonder why it hasn't conquered the technological world already.

The reality is not such a fairy tale. Graphene's carbon forebears were once hyped in much the same way. Yet fullerenes have found hardly any practical applications. And although nanotubes have done better, they are costly to produce and difficult to control. Their subdued industrial impact is a lesson in just how hard commercialization of a new material can be.

Yet the story of nanotubes has some encouraging features. High-tech electronics applications are still years in the future, but a more low-tech application — nanotube-based conducting films for energy storage or touch screens — is much closer to commercialization. Another, comparatively straightforward use — nanotube-reinforced composite materials for aeroplanes and automobiles — is now reaching the market. Anticipating growing demand, nano-tube manufacturers have scaled up production to many hundreds of tonnes a year.

For that very reason, the graphene manufacturers following in their wake may have hit on the right moment to start mass-producing the sheets. Graphene is being considered for the same types of application as nanotubes, but it has some key advantages in ease of production and handling, and should benefit from two decades of research with nanotubes. That hindsight also means that graphene manufacturers have a better idea of which applications are worth chasing, and of how to avoid the false starts that nanotubes made in their first decade.

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