Materials

Graphene: Everything You Need to Know About the ‘Miracle Material’

Graphene's unique properties make it one of the world's most exciting materials, and it’s hard to think of an industry or technology that wouldn’t be transformed if it lives up to the hype.

If you’re looking to buy real-world products made with graphene, the list is still very short. You can buy graphene-reinforced tennis rackets, bicycle tires, and motorcycle helmets. But the small quantity of graphene in these products is designed to deliver more marketing buzz than a real technical advantage, said Jesus de la Fuente, founder and CEO of Graphenea, a company that manufactures and sells graphene to academic researchers and R&D departments.

De la Fuente told Seeker that the first widespread commercial applications for graphene will probably be in the field of biosensing. While not as sexy as flexible flat-screen TVs and smart tattoos, biosensors are critical components of medical diagnostics and the drug discovery process. Modern biosensors are built into chips that can detect the smallest presence of targeted molecules.

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Graphene boasts several key properties that make it an ideal biosensor. The first is surface area. With a single-layer sheet of graphene — even on a tiny, micrometer-scale chip — every last carbon atom is exposed to the environment. And because graphene is highly conductive, you can run a current through it and measure the slightest changes in conductivity across the electric field.

The first wave of commercial graphene biosensing devices is already hitting the market. A company called Nanomedical Diagnostics sells a handheld device called the Agile R100 that’s based on “field effect biosensing” technology. Pharmaceutical companies in the early testing stages can quickly see whether a new drug is reaching its target, bypassing the slower and more expensive assay process. 

Ferrari at the Cambridge Graphene Center is excited about the next wave of graphene-enabled biosensors. Since graphene is flexible, durable, and made entirely of carbon, it’s highly biocompatible, meaning it can be introduced into the body without deteriorating or triggering adverse reactions. Researchers are working on tiny graphene sensors that can be mounted on a tooth to monitor respiration or in the brain to predict seizures. Others are trying to make artificial graphene retinas for the vision-impaired.

“Since graphene is so thin, you can create very thin circuitry that can be implanted in the back of the eye to transmit information to the brain,” said Ferrari.

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After biosensors, batteries are next in line for harnessing the unique properties of graphene. Both large global companies and small startups are racing to bring a graphene-boosted battery to market, said De la Fuente. That’s because lithium-ion (li-ion) batteries — the rechargeable batteries found in cell phones, laptops and electric cars — have reached a limit as to how much energy they can store and how quickly they can charge.

Since graphene is the world’s best electrical conductor, it holds the promise of doubling or even tripling the life of today’s li-ion batteries while shrinking charging times from hours to minutes. To achieve such a quantum leap in battery power, researchers are experimenting with battery electrodes made from pure graphene and graphene composites.

But biosensors and batteries are just the beginning when it comes to graphene’s transformative potential. De la Fuente says that 60,000 scientific papers are now published every year related to graphene.

“Graphene is just the tip of a massively huge iceberg that we just started to scratch from the top. We’re at the very beginning of a very long field of research and technology that will last for decades to come.”

MIT researchers made headlines recently when they showed off a futuristic construction material made from 3D-printed graphene that’s incredibly light — only 5 percent density — but 10 times stronger than steel. And researchers at the University of Manchester, where graphene was first produced in 2004, are testing a graphene oxide sieve that may provide a cheap and energy-efficient way of producing fresh drinking water from seawater.

So what’s standing in the way of our graphene-powered future? Price used to be a major obstacle. Back in 2006, when graphene production was in its infancy, the price for even a tiny piece of graphene was absurdly high. “We’re talking about trillions of dollars per gram,” Ferrari said.

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Not anymore. De la Fuente told Seeker that the sales price of his graphene has dropped 27 percent per year since Graphenea opened in 2010. The price of single-layer sheet of graphene is now as low as 50 cents per square centimeter, the same as silicon, said De la Fuente.

And new, even cheaper methods of making graphene are showing up every day. The original technique was to exfoliate single layers from graphite. Next, researchers figured out how to “grow” layers of graphene in the lab using a method called chemical vapor deposition. Recently a team at Kansas State University stumbled on a new method that creates bucket loads of powdered graphene from igniting oxygen and hydrocarbon gas. Boom.

As graphene gets cheaper and more abundant, it’s worth asking, given all of its miraculous properties, will graphene eventually replace silicon as the foundation of our computers and electronic devices, ushering in a new era of crazy thin and fast machines? Not quite.

Graphene alone will never replace silicon for the simple fact that graphene isn’t a semiconductor. A sheet of pure graphene conducts electricity brilliantly, but it can’t shut off the flow of electrons. That’s the difference between a conductor and a semiconductor. For graphene to be used in processors, it will almost certainly need to be combined with other materials. This will diminish some of graphene’s superpowers, but perhaps still outperform the competition.

Ferrari at Cambridge said that there are around 2,000 other materials with the same, layered structure as graphite, the source of graphene. Now that researchers know how to separate graphite into single layers, they can employ the same technique to create all sorts of new monolayer materials, some of which are excellent semiconductors.

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When single layers of these new materials are stacked and sandwiched between layers of graphene at varying angles, “the combinations are nearly infinite,” said Ferrari. “So graphene is just the tip of a massively huge iceberg that we just started to scratch from the top. We’re at the very beginning of a very long field of research and technology that will last for decades to come.”

As for the hype around graphene, it’s par for the course for any new advanced material. In Gartner’s 2016 Hype Cycle for Semiconductors and Electronics Technologies, industry analysts place graphene squarely at the “peak of inflated expectations.” The next phase is the “trough of disillusionment” as investment flags and initial expectations fizzle. Graphenea CEO De la Fuente fully expects to enter the “trough” in the coming year. 

Ferrari at the Cambridge Graphene Center is optimistic about graphene’s fate, but not blind to the challenges.

“Nobody knows the future. It can all end up as nothing as well. We’re in a situation where graphene has a lot of potential, but will take a lot of hard work at least for the next 10 to 15 years to make this become a reality,” said Ferrari. “We don’t know if it will succeed or not, but I’m becoming a lot more positive about the outcome.”

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