Researchers have found a way to turn cheap, everyday cooking oil into the wonder material graphene - a technique that could greatly reduce the cost of making the much-touted nanomaterial.
Graphene is a single sheet of carbon atoms with incredible properties - it's 200 times stronger than steel, harder than diamond, and incredibly flexible. Under certain conditions, it can even be turned into a superconductor that carries electricity with zero resistance.
That means the material has the potential to make better electronics, more effective solar cells, and could even be used in medicine.
Last year, a study suggested that graphene could help mobile phone batteries last 25 percent longer, and the material has the potential to filter fuel out of thin air.
But these applications have been limited by the fact that graphene usually has to be made in a vacuum at intense heat using purified ingredients, which makes it expensive to produce.
Until we can find a cost-effective way to mass produce the over-achieving material, it's pretty much limited to labs.
But scientists in Australia have now managed to create graphene in normal air conditions, using cheap soybean cooking oil.
"This ambient-air process for graphene fabrication is fast, simple, safe, potentially scalable, and integration-friendly," said one of the researchers, Zhao Jun Han from Australia's CSIRO.
"Our unique technology is expected to reduce the cost of graphene production and improve the uptake in new applications."
The team has called the new technique 'GraphAir' technology, and it involves heating soybean oil in a tube furnace for about 30 minutes, causing it to decompose into carbon building blocks.
This carbon is then rapidly cooled on a foil made of nickel, where it diffuses into a thin rectangle of graphene that's just 1 nanometre thick (about 80,000 times thinner than a human hair).
Not only is this technique cheaper and easier than other methods, it's also a lot quicker - to create graphene in a vacuum takes several hours.
Zhao told the Australian Broadcasting Corporation (ABC) that the technique could reduce the cost of making graphene 10-fold.
Not only that, but it offers a more sustainable option for recycling waste cooking oil.
"We can now recycle waste oils that would have otherwise been discarded and transform them into something useful," said one of the team, Dong Han Seo.
The question now is whether this new technique can be scaled up - finding a cheaper way to make graphene is awesome, but the graphene film produced so far was only 5 cm (1.9 inches) by 2 cm (0.8 inches) in size.
The team says that the largest film they can make using the technique right now is around the size of a credit card.
To really make graphene fit for commercial use, researchers will need to produce films that are a whole lot larger than that.
"The potential's enormous," David Officer, a graphene expert from the University of Wollongong in Australia, who wasn't involved in the study, told the ABC.
"[But] the question will be whether you can economically scale a method like this, where they've sealed it inside a furnace tube, to create and handle metre-sized films."
The team is now looking for commercial partners to pursue this goal.
But they're not the only researchers working on it - last week, a team fromKansas State University patented a simple technique that creates graphene using only hydrocarbon gas, oxygen, and a spark plug. No vacuum required.
Time will tell if they can use it to effectively make large films of graphene in one go, but it's nice to know that researchers around the world are working on finding a way to take this incredible material out of the lab and into our lives.
The research has been published in Nature Communications.
Researchers develop high-quality graphene for 1/1000th of previous cost
After the 2010 Nobel Prize for physics was awarded to its discoverers Andre Geim and Konstantin Novoselov, expectations for graphene were high. The properties of this single sheet of carbon atoms were expected to be exceptional: strong, transparent, electronically and thermally conducting and chemical inert. Numerous potential applications were proposed including smartphone screens, solar cells, fuel cell membranes, devices for drug delivery and even condoms.
Yet the divide between the number of hopeful scientific publications on promising applications and the actual production of large pieces of high-quality, single-crystal graphene grew into an abyss. The trough of disillusionment followed the peak of inflated expectations.
‘Although enormous amount of efforts have been devoted to graphene research, there is still a large gap between academia and industry, and how to cross the valley of death from research to business is still an open question’, wrote Zhu in his PhD thesis. He refers to the ten year European research programme European Graphene Flagship worth one billion euros.
Geim and Novoselov produced their graphene with pencil markings and scotch tape. By repeatedly sticking fresh bits of tape against a pencil mark, the graphite layer became thinner and thinner until a single sheet of carbon remained. This was called the exfoliation method. It seems an endearingly simple way to obtain a Nobel, but not a very efficient way of production. And although a dozen of other methods exist, exfoliation is still regarded as the way to produce graphene with the lowest number of defects and highest electron mobility. But the costs are enormous: a flake the size of a hair made in this way costs more than €1,000 – making graphene one of the most expensive materials on earth, according to Nature.
Yet, all you need to produce graphene, natural gas and copper, is available in most kitchens, said Zhu. What’s more, he has demonstrated millimeter-sized graphene crystals made by chemical vapour deposition of methane on a copper sheet. He leads of low-pressure mix of hydrogen, methane and argon over a copper sheet at a temperature of 1,000 degree celsius. The copper acts as a catalyst in stripping the hydrogen from the methane, leaving pure carbon that sticks to the surface and perfectly aligns with other carbon atoms into this endless sheet of pure graphene.
Other parties need ten hours to produce graphene by deposition. Zhu, however, has brought back the production time to about one hour by splitting the quartz tube in which the deposition takes place from the oven that surrounds it. After deposition, he simply slides the furnace away to speed up cooling.
“Now a single piece of graphene costs about €1,000”, said Zhu. “We expect to reduce the price by a factor of thousand to about €1 per piece in a few years.”
But is it just as good? Zhu demonstrated that millimeter-sized piece of graphene was, in fact, one single crystal by freely moving the electrons around in it. Together with his colleagues, he applied a perpendicular magnetic field to the graphene. The field pushed the free moving electrons into circular trajectories without any scattering. Thus he proved that the synthetic graphene was flawless.
Another demonstration is the pressure sensor Zhu made and which he published in Applied Physics Letters in 2013. It consists of a silicon nitride diaphragm with a 0.3 mm hole in a silicon support. The diaphragm is covered with graphene. The membrane stretches with the pressure difference over it, which changes the electrical resistance. The device works as a pressure sensor with a sensitivity of 8.5 mV/bar.
Zhu, who won the 2011 Young Wild Idea Prize,is profiling himself as Mr. Graphene ever more strongly. He’ll defend his PhD thesis on the March 3, 2015. As for his further goals, he says: “I want to make graphene real and bring it into daily life. Bring it into products anyone can touch.”
A material that’s better than graphene? Scientists say they’ve found it
What could be better than a material that’s super flexible, only one atom thick, and is 200 times stronger than steel? A material that’s equally strong and flexible, also only one atom thick, and inexpensive.
Scientists are asserting that this new discovery could potentially upstage the world’s greatest wonder material, graphene.
A physicist from the University of Kentucky is now working with scientists from Daimler in Germany as well as the Institute for Electronic Structure and Laser (IESL) in Greece to create a new material made from elements such as silicon, boron, and nitrogen. These building blocks mean that the material will be less expensive, more stable, and ultimately better than graphene - in theory, at least.
"We used simulations to see if the bonds would break or disintegrate - it didn’t happen," said Madhu Menon, a physicist in the UK Centre for Computational Sciences. "We heated the material up to 1,000 degrees Celsius and it still didn’t break."
It sounds impressive, but to date, the material hasn’t actually been made. It only exists on computer simulations; however, scientists are working to rectify this now.
Menon, Ernst Richter (from Daimler) and Antonis Andriotis (from IESL) have used state-of-the-art theoretical computations to demonstrate the feasibility of creating a one-atom thick, 2D material made from the aforementioned Earth-abundant elements, and the material could have possible applications beyond what graphene can currently do.
To clarify, graphene, for all its potential, has a big downside: It isn’t a semiconductor and, as a result, has very limited application in digital technology.
This led scientists to continue working on finding alternative materials, and that led to the discovery of three-layer materials known as transition-metal dichalcogenides (TMDCs), which can be used to to make digital processors. Unfortunately, while they can process more efficiently, they are thicker and not so abundant on Earth.
"We know that silicon-based technology is reaching its limit because we are putting more and more components together and making electronic processors more and more compact," Menon said. "But we know that this cannot go on indefinitely; we need smarter materials."
The calculations that studied the possibility of this new material were made on computers at the UK Centre for Computational Sciences. The next step is to now produce the same results the computer tests generated in a lab setting… and of course, actually make the material.
"We are very anxious for this to be made in the lab," Menon said. "The ultimate test of any theory is experimental verification, so the sooner the better!"