Since 2013, the Graphene Flagship has brought together academic and industrial researchers to push graphene and layered materials to the forefront of European scientific research. But when – and how – did everything begin? Join us on a journey back in time as we tell the tale of graphene's rich and iconic history.
Graphite is the most stable form of carbon, and it has been known since ancient times. In graphite, the carbon atoms arrange themselves into a series of layers, bound together by weak interactions. This unique structure makes it a great lubricant, a good conductor of heat and electricity, and the ideal ingredient for pencils: because the layers easily slide apart, they can be precisely transferred to a piece of paper, allowing us to write, draw, imagine and wonder.
Among these wonderers were scientists, who first dreamt of isolating single layers of graphite in the late 1940s. They predicted that such a material – the thinnest ever conceived – would have very unusual electronic properties, due to both quantum phenomena and relativistic effects, because the laws of physics can be very different at the nanoscale. But could they be really different enough to allow a single layer of graphite to exist? Many of the brightest minds thought it would be unstable, and some believed it to be utterly impossible – a theoretical utopia.
The graphene journey begins
More than anything, scientists love to explore the unknown. They chase their dreams, sometimes fighting against all logical odds, in the ceaseless pursuit of knowledge and understanding. So it wasn't long before the hunt began for a single, pristine layer of graphite.
In 1962, they gave it a name: graphene. Because the layers of graphite peel off so easily, the keen investigators thought that would be the best way to obtain it. They attempted to 'exfoliate' single layers of graphene using different mechanical techniques, including 'the drawing method' – literally trying to draw the finest lines possible with an incredibly sharp graphite point. But alas, it seemed like an insurmountable quest. Their best results were graphite sheets 10 nanometres thick, 2000 times thinner than a human hair, but still 30 times thicker than a single layer of carbon atoms.
But after decades of intense theorycrafting and research, back in 2004, on an otherwise unremarkable Friday night in Manchester, the dream finally came true.
Pioneers make their mark
Every week, Andre Geim and Konstantin Novoselov would stay in the lab after work to discuss new ideas and try out unconventional experiments – some of which are just as whimsical as the concept of drawing atomically-thin strokes of graphite with a super-sharp pencil. Indeed, in a running theme, one of their experiments also involved playing with office supplies. They grabbed a roll of sticky Scotch tape, tore off a few pieces, and began to attach and detach them from a big chunk of graphite. Some fragments came off that looked extremely thin, almost invisible to the human eye and nearly indistinguishable from the tape itself.
Could this be graphene? Perhaps a microscope determine the nature of these delicate carbon films.
Novoselov remembered that a few days earlier, he overheard some colleagues boasting about a new tunnelling microscope in their department. This device was capable of rendering sharp images of nanoscale objects and, at the same time, could measure their electrical properties. Right away, Novoselov knew that this device was the key to elucidating their material. And Eureka! The tunneling microscope killed two birds with one stone: it enabled them to observe, for the first time, individual layers of graphene – called graphene monolayers – and allowed them to demonstrate that the physical behaviour of graphene matched their theoretical predictions.
Was graphene about to enter the realm of modern electronics? The answer is history.
History, written in graphene
It quickly became clear that graphene would be sticking around. It was no longer merely a fantasy – graphene could now be isolated easily from graphite, and it was stable at room temperature and ambient pressure. Even further than this, measurements showed that graphene was a 'zero-gap semiconductor,' a rare type of material in which electrons can seamlessly jump to the conduction band, resulting in unique and unusual physical properties
Zero-gap materials are extremely sensitive to small changes in their environment, such as pressure, magnetic field or the presence of molecules. In addition, further experiments showed that graphene conducts heat better than any known material, and that it conducts electricity even better than copper and silver. This rare combination of unusual properties makes graphene an ideal candidate for next-generation sensors, electronic devices, optical instruments and more.
A one-atom-thin layer of carbon may sound fragile, but graphene is flexible and 200 times stronger than steel. Once again, the classical laws of physics break down at the nano-scale – the effects we see in graphene are unthinkable in metals, silicon and plastics. The isolation of graphene kicked off a whole new era in materials science.
Graphene is also the first two-dimensional material: "it expanded our toolbox to a whole new dimension," as Geim often says. And ultimately, it did. Scientists have gone on to discover that other materials can be exfoliated too, just like graphite, leading to a family of two-dimensional and layered materials with extraordinary properties. By combining them like ingredients in a sandwich, we can manufacture devices for all sorts of different applications that would've been unfathomable just a couple of decades ago.
Nobel recognition for a noble achievement
Geim and Novoselov didn't expect this at all. They were purely driven by scientific curiosity, in pursuit of unfound knowledge and undiscovered possibilities. They were not looking for fame or fortune, so they decided not to file a patent on the new method to isolate graphene – much like how Marie Curie decided not to patent her discoveries for the greater good.
In October 2010, almost exactly six years after their original Science paper was published, the Royal Swedish Academy of Sciences gave them a call. Geim and Novoselov had been selected for the most prestigious award a scientist can get – and like Curie, they were presented with the Nobel Prize just a few years after their ground-breaking discovery.
The Nobel committee highlighted the strength of graphene, famously stating that "an invisible hammock made from graphene could hold a cat without breaking" – as well as shining the spotlight on its superlative versatility, in that "it could give new twists to quantum physics, (…) speed up transistors and computers, and be suitable for producing transparent touch screens, light panels and solar cells."
Soon after, the European Commission decided to invest €1 billion in a one-of-a-kind multidisciplinary project, to boost research into graphene and layered materials, and to put the EU at the forefront of this new technological innovation.
They called it the Graphene Flagship – but that is a story for another day.