Most people who know a bit about Graphene, whether because they are interested in what goes on at an atomic level or because they follow the stock market and the recent flotation of Applied Graphene Materials might think that the substance was discovered by Andre Geim and Kostya Novoselov of the University of Manchester, who were awarded the Nobel Prize for Physics in 2010 for their work in the field. Although they perfected it and also brought it to the attention of mainstream quantum physicists, it was actually named in 1987 by Hanns-Peter Boehm of Ludwig-Maximilians-Universität in Munich, who first described a single-layer carbon foil in 1962. He is widely accepted as one of the pioneers in the field of graphene development, but the actual history of graphene in fact goes back much further, into the nineteenth century.
History of graphene
Benjamin Collins Brodie, at the time a very senior member of the Chemical Society and about to become its president, described the highly lamellar structure of thermally reduced graphite oxide. He is known for his work on the structure of beeswax – for which he was given the Fellowship of the Royal Society and the Royal Medal, but this work led him to consider lamellar structures in general and it was really only the technology of the time that held him back from further discoveries. It wasn’t until 1916 that the structure of graphite was discovered and the theoretical existence of graphene was not really considered seriously until 1947 by P R Wallace. An anomalous occurrence in the magnetic field suggested that there must be a substance with a lamellar property, but no one could find or identify it apart from theoretically. Electron microscopy finally gave the scientific world images of few-layer graphite in 1948 and it was not long that single graphene layers were observed by Ruess and Vogt, but there was still no chance that they could be isolated, let alone used in any practical way. In the 1970s, a few researchers managed to grow single layers of graphite using other molecules as a substrate, but more than thirty years were to elapse before usable graphene became a possibility.
Enter Geim and Novoselov
Working at the University of Manchester, Andre Geim and Kostya Novoselov extracted single-atom-thick crystallites from bulk graphite in 2004. They did this by pulling graphene layers from graphite and transferred them onto thin SiO2 on a silicon wafer. This process is called micromechanical cleavage, but more often scientists use the shorthand ‘Scotch tape technique’. The SiO2 electrically isolated the graphene and interacted with it, but only weakly. This created almost charge-neutral graphene layers and although there had been patents for the method already filed, this was the first time that any of the theoretical findings had been able to be proved on the substance. At first, most of the excitement in the physics community arose from the fact that the graphene ‘grown’ by the Scotch tape technique proved many equations previously only existing as theories, the actual properties and potential of graphene quickly became apparent.
Potential uses of graphene
In 2008, graphene was the most expensive material in the world, costing an eye-watering $100,000,000 per square centimetre. It is still expensive, but obviously nothing like so much, with companies producing large quantities, partly thanks to an EU grant and money raised from the flotation of the main producing company. The potential uses become more in number every day and it is now expected to be a commonplace in everyone’s lives in not too many years. Because graphene is thin, flexible and also very strong, it will be used in display screens, electric circuits, and solar cells most commonly, but it has other properties which make the possibilities very exciting. In the medical field, it has been discovered that using graphene as a substrate enhances DNA recovery by over 50% and is likely to be invaluable in gene research. Graphene is also ideal for integrated circuits, transistors and transparent conducting electrodes. There has been a very serious suggestion put forward that it will made an effective desalination barrier and of course for those countries with limited fresh water who routinely use desalinated seawater, this is a very exciting proposition, as the methodology is likely to be simpler and cheaper to that currently in use. With more than a dozen other applications already being developed and many more on the way, graphene will soon be as common to the average person as glass or plastic – and probably much more useful.