Grasping Graphene: Putting the Facts – and the Hype – in Context
Major breakthroughs in material science—a vitally important, if distinctly unsexy, field of study—tend to be few and far between. So it is all the more remarkable that, in recent months, the buzz around graphene, a unique form of carbon that some have heralded as a “miracle material,” has risen to a veritable uproar. Indeed, many of graphene’s potential applications could have tremendous implications for cleantech. The challenge for savvy investors and businesspeople today is to make sense of all this information: What do we really need to know about graphene? And what might we expect to see from it in the future?
Graphene specifically refers to single-layer sheets of interlocking carbon atoms, arranged in a pattern of repeating hexagons. These sheets are only one atom thick—about a million times thinner than paper—and are widely described as two-dimensional. Due to its distinctive chemical composition and structure, graphene has an array of extraordinary properties: it is currently the strongest material known to man (defined by the amount of force needed to change its structure); it is extremely flexible and fully transparent; and, perhaps most significantly, it is extremely conductive of both heat and electricity. Electrons can move up to 100 times faster in graphene than they can in silicon, the material used in most photovoltaic cells.
As researchers have documented these properties in the past few years, other scientists and the media have proposed countless applications for graphene, many of which relate to cleantech. Most prominently, researchers at the University of Maryland have created an ultra-thin solar cell based on graphene that can achieve conversion efficiency similar to that of existing silicon-based cells.
Moreover, Spain’s Institute of Photonic Studies contends that, theoretically, cells using graphene could achieve a conversion efficiency of up to 60 percent, roughly double that of current photovoltaics. Graphene could facilitate the development of thin, flexible, transparent solar panels that could be easily attached to buildings, vehicles, electronic devices, or clothing. Some even suggest that graphene-based paints could be applied to surfaces to allow them to generate electricity. Such developments would clearly and profoundly impact the existing solar industry, as well as the energy industry more broadly.
In addition to solar, graphene may also have important potential applications for electronics—particularly smaller, more efficient transistors for computer chips and thinner, more flexible screens for electronic devices—as well as for material strengthening and advanced medical devices. Taking every wild idea at face value, the possibilities seem endless.
That said, however, we’re not there yet. Graphene has a long way to go before it can be considered a legitimately disruptive technology. Researchers have yet to come up with a cost-effective way to produce graphene at the commercial scale, and much additional research will be necessary before it can be used to replace materials like silicon. For example, unlike with silicon, there is currently no way to “turn off” the flow of electricity through graphene, making it more difficult to use as a transistor. While scientists are exploring ways of layering graphene with other materials to alter its conductive properties, it will undoubtedly be a while before it can be deployed on a meaningful scale.
There are other issues too. A research team at Rice University has shown that, when graphite is produced, minor flaws often exist at the edges of the sheet, which can introduce tension and decrease the overall strength of the sheet. A Brown University study suggests that, if accidentally ingested, graphene may be toxic, as the sheets are so thin that they can easily pierce cell membranes. If the carbon framework is not kept entirely free from impurities, the conductive properties of the graphene may be significantly altered.
Marko Spasenovic, a researcher at the Institute for Photonic Studies, argues that we are near the peak of the “graphene hype curve,” after which expectations will fall dramatically, as graphene proves less “miraculous” than it was worked up to be, and subsequently rise to a level that accurately reflects its true potential. In a similar vein, Professor Tomas Palacios of MIT cautions that, while many proposed applications of graphene may be technically viable, it is unlikely that more than a handful will reach the production stage in the short- to medium-term.
The future of graphene, then, is simultaneously full of possibility and fraught with risk. While it seems unrealistic that graphene will be the game-changer some analysts make it out to be, companies that are able to successfully leverage this unique material’s strengths, as the technology develops, may be looking at a prime opportunity for serious growth.
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About the blogger: Lucas Rehaut is a rising senior at Columbia University and a research intern with the Cleantech Group. He is especially interested in the intersection of sustainability, technology, and business strategy. Lucas enjoys solving problems, reading, and meeting new people (and dogs).