Representation of graphene. Credit: Wikipedia.I have wondered for a long time how materials scientists feel about one substance that has got a lot of attention in the last few years. Graphene. Touted as a wonder material and reported on several times in recent years by yours truly and countless others. It is a marvelous thing, single graphite layers imagined as some kind of never-ending, two-dimensional molecule with emerging electrical, optical and physical properties that seem quite astounding in many ways.
But, when they were doling out the Nobel Prize for Physics in 2010, I wondered why they alighted on that compound and the Manchester experiments from the decade prior to that. Hadn't chemists discovered graphene in the nineteenth century? Well, yes, they had. I vaguely recall it being mentioned in lectures by carbon and coal chemist Harry Marsh at Newcastle University in discussions of carbon allotropes long before buckyballs and carbon nanotubes were recognized.
The nineteenth century saw many wondrous discoveries, elemental discoveries, new materials, electromagnetic phenomena. English chemist Benjamin Collins Brodie recognized the highly layered nature of thermally reduced graphite oxide as early as 1859 having reported the atomic weight of graphite in the Philosophical Transactions of the Royal Society of London that year. Powder diffraction was used to solve the structure of graphite in 1916 and Kohlschütter and Haenni described what they called graphite oxide "paper" in 1918. In trying to develop a theory for the electronic properties of bulk graphite, P R Wallace underpinned his work with a theory of graphene in 1947.
Then, Ruess and Vogt used electron microscopy to show a few layers of graphite in 1948 and subsequently a single layer. In 1962 Boehm and colleagues had published details of their work on graphite flakes, which were single or multilayer. But, it was in the early 1970s that chemists found a way to deposit carbon in graphene monolayers on to other materials.
It is well known that graphene's history spans more than a century of chemical research. There is a vast chemical literature, of literally hundreds of papers from the early 1960s and on the topic of epitaxially grown graphene from the 1970s onwards. The modern legend of Scotch tape and pencils has created a landmark in science history, one that some have questioned. At the time of the Nobel announcement, several scientists alleged factual errors in the Nobel committee's reasoning as it was published and the website was subsequently updated. Others suggested that the award was premature and that perhaps work by physicist Philip Kim of Columbia University in New York on the properties of graphene should have been incorporated into the Prize. Graphene chemist Walter de Heer of the Georgia Institute of Technology in Atlanta highlighted fifty years of epitaxial growth of graphene that pre-dated the Nobel work.
It is unlikely that the Nobel committee ignored the prior art. They made the award in recognition of groundbreaking experiments, not the "discovery" of graphene. Moreover, others have pointed out that it is the freestanding nature of the Manchester graphene as opposed to the supported and bonded sheets of earlier work that make it worthy. It is in some ways regrettable (from a chemist's point of view) that the physics community garnered recognition for an essentially chemical discovery; chemistry often bows to biology in the Nobel awards too. However, the nineteenth century scientists, Faraday and many others, were commonly polymaths, interdisciplinarians, in an era before the distinct disciplines of chemistry, physics, materials science, even, were being demarcated. MIT's Mildred Dresselhaus is one of the pioneering polymaths of the modern era, having been responsible for a vast amount of what we now know about carbon materials including graphite, graphene and carbon nanotubes.
"One of the pioneers of graphene from the 1980s and 1990s is Millie Dresselhaus!" says Joerg Heber, Managing Editor for the physical sciences at Nature Communications confirms. "Amongst others, she studied graphite, carbon nanotubes and graphene." Heber, who commented in detail about the Nobel graphene story at announcement time and some of the controversy, adds that, "Graphene certainly has come a long way since carbon and its allotropes were studied by chemists. Focussing on the unique properties of nanoscale materials, Geim, Novoselov and other pioneers in the field have created an entirely new research field, where chemistry, physics and materials science come together to make use of the strong chemical bonds between the carbon atoms in two dimensions. There will still be a lot more exciting discoveries ahead of us."
Graphene is a wondrous and remarkable material. It holds much promise and in the last few years that promise is gradually becoming manifest as techniques for making it and handling it evolve and mature. This material will have its day because of the light shed on it regardless of its chemical history.
David Bradley blogs at http://www.sciencebase.com and tweets @sciencebase, he is author of the popular science book "Deceived Wisdom".