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Guest post by Chemistry World intern Dan Johnson
Catching a clip of some ‘fashion week’ or other on the news, I’ve often wondered why those spindly catwalk models are wearing a tent for a skirt, a plant pot for a hat and all the while giving you that haughty to look as if to say ‘You still wear clothes?’ What these people are wearing seems to have nothing to do with mere normal people. Mention this out loud though, and you’ll be told: ‘they set the trends that change your boring clothes, you philistine’.
Non-scientists are often left similarly confused and befuddled by ‘blue-skies’ scientific research. The proposed benefits of such research can be so shrouded in mystery that it begs the question: ‘What’s this got to do with me? How will this affect my life?’
One man who believes passionately in the benefits of such research is Andre Geim – one of the discoverers of graphene, which won him the 2010 Nobel prize in physics. In a recent Perspective piece in Nature, he lays out the new direction for research in his own personal fiefdom: two-dimensional materials.
— Building van der Waals heterostructures © NPG
Graphene has been much touted for its miracle properties since its discovery in 2004. It was the first 2D material to be discovered, and is the thinnest, lightest and strongest material ever produced. Of course all these superlatives mean it has plethora of promising applications. But according to Geim, ‘graphene’s low hanging fruits’ –characterising and investigating the material – have been harvested, leaving the difficult task of turning wonder properties into wonder applications.
Geim contends that easier to reach fruit is in ample supply if only we turn our attention to other two-dimensional structures. As graphene itself has shown, the properties of 2D structures can be astounding, and monolayers of crystals like hexagonal boron nitride (hBN) or molybdenum disulfide could be just as mind blowing as graphene.
He goes further. Heterostructures can be made by ‘stacking different 2D crystals on top of each other’. Imagine building a Lego brick wall, but the bricks are one atom thick. Sound fun? Judging by the precision needed to build these structures, it’s a playful yet pedantic scientist’s dream. In the future, any number of ‘blocks’ could be marshalled into the wall, using the properties of other 2D layers to complement those of graphene. There are plenty to choose from. Looking at the table supplied by Geim (see below) shows just how much research is left to be done.
An example of the power of this idea is the combination of graphene layers with hCN layers to form a superconductor. This could help graphene replace silicon as the linchpin of computing, helping technology keep up with Moore’s Law – the observation that the number of transistors on a circuit board doubles every two years .
Geim, with his famously playful research style, doesn’t wish to speculate too much, though. He’s a strong supporter of blue skies research, but is more reticent when asked to pin down definitive applications. This is shown by his bemusement towards the new Graphene Institute in Manchester, an attempt to capitalise on the UK’s head start in the field: ‘I’m not interested in going into industry or property development or creating ‘graphene valley’ as the Government would like me to’. It’s a bit silly for society to throw a little bit of money at something and expect it to change the world. Everything takes time.’
Here then, is a man whose big idea is the big idea itself. But anyone looking for the direction of 2D materials over the next few years would do well to hang on to his coattails.
— Current 2D library © NPG