Graphene, the next disruptive innovation?
If you reading this then none of the cataclysmic events predicted by Mayans for December 21st, occurred. Hooray, but let’s hope it’s not because they are late! Anyway, I say let’s celebrate this with looking back at 2012 from a materials scientist point of view, and spend some time on what I think was arguably the “celeb” material of the year, graphene.
Luckily and not surprisingly 2012 in science (UN International Year of Sustainable Energy for All) involved many significant breakthroughs and surprising turns of events, including scientists from CERN reporting the first indirect evidence supporting the existence of the Higgs boson; IBM engineers developing the first working 9 nm transistor using nanotubes as an alternative technology to the silicon as well as making the first steps towards the commercializing the production; demonstrating the storage of a single bit on just a dozen super-cooled iron atoms instead of a million, so making way to the future ultra-high-density storage media; Intel commercializing the world’s first 22 nm microchip family showing greatly increased computational power and energy efficiency; and researchers from IBM (again!) revealing a new lithium-air battery with far greater energy density than the currently used lithium-ion batteries which could be utilized in the production of electric vehicles. And of course, I can’t just pass by the groundbreaking work of Robert J. Lefkowitz and Brian Kobilkathe on G-protein-coupled receptors (GPCRs) that was awarded the Nobel for Chemistry in October, once again disrupting the “holy cycle” of must win topics (materials chemistry, biochemistry, organic chemistry and physical chemistry). This is just to name a few of the decisive events of the year, but to me, as a former materials scientist, the big thing was graphene looking more and more like the next big disruptive technology. Therefore, I’d vote for this relatively new carbon allotrope as the “celeb” material of the Year of Sustainable Energy. Kind of fits in, doesn’t it?
The story of graphene is a nice continuation of what was started in 1985 with fullerenes or buckyballs (C60), another allotrope of carbon, that were acknowledged by the Nobel Committee when Richard Smalley, Robert Curl and Harold Kroto jointly won the award in 1996. The structure was also identified some years earlier by Sumio Iijima, from an electron microscope image, who, by the way is most known for his significant contribution to the discovery of carbon nanotubes at NEC in 1991, yet another material made of carbon. Although CNTs were discovered more than 20 years ago they’re yet to fulfill the promise and hope they promise. It did not take too long before another C allotrope, namely graphene, the first 2 dimensional atomic crystal available to us gained a following among materials scientists as the following chart based on the yearly distribution of graphene related ACS publications clearly demonstrates. It also did not take long before the research field, well, Andre Geim and Konstantin Novoselov from the University of Manchester was awarded with a joint Nobel Prize in physics for their groundbreaking research in 2010.
The boom of graphene related papers published by ACS
But what is it that brings this material described as a one atom thick honeycomb lattice of carbon atoms into focus and makes industry leaders consider it as the next disruptive innovation? It’s not enough to have a combination of unique properties (some of them reaching the predicted theoretical limits), such as extreme high intrinsic mechanical strength and elasticity (130 GPa and 1 TPa, respectively), superb electrical and thermal conductivity (>3,000 W mK-1), optical transparency, impermeability to gases, the ability to maintain a million times higher density of electric current than copper does or the fact that graphene is particularly prone to chemical functionalization but the large scale production of these materials has yet to be solved. Luckily different applications require different grades of graphene, therefore different syntheses to be used, obviously meaning that the closest to reach applications are determined by the cheapest and the most energy efficient production methods. Some careful projections from industry leaders say that working prototypes of flexible electronic devices, such as foldable e-papers and organic LEDs or touch screens will be available in just a few years, because these applications need only medium quality graphene that can be produced even via CVD (chemical vapor deposition). Meanwhile, applications, such as high-frequency transistors, that are set to replace III-V semiconductors (e.g. GaN), or photonic applications (e.g. tunable mode-locked lasers or photodetectors) that requires higher quality defect free graphene sheets are not expected to be available before 2020-2030, because they need the commercialization of a cost-effective graphene transferring technology. Another issue that may delay graphene’s taking over the market is in applications, such as logic transistors, where the solution is to beat the current Si technology that will most extended below the 10 nm ‘holy grail’ limit, not to mention beating silicone the newly discovered silicon analogue of graphene also with superb semiconductor properties and relevance to nano scale computing.
Although it’s gonna take some time to see the graphene devices rolling out, or graphene in bio-applications, such as tissue engineering and drug delivery, some other, maybe less sophisticated graphene-based products are already under heavy development, thanks to processes like liquid-phase exfoliation, which gives fairly low price range for mass production (by the ton). These applications include transparent protective coatings, filters for gases and liquids, inks or active medium in solar cells. So, there is a lot in the pipeline to say the least and chances are that we are just scrathing the surface. Disruptive innovation? Very likely if large-scale production of research quality samples is getting solved.