Graphene is steadily making its way from research laboratories to real applications, but scientists - including Nobel Prize laureate Konstantin Novoselov, the wonder material’s co-discoverer - are already looking further ahead to a range of 2D substances that will allow tailoring materials to the exact requirements of various devices.
Imagine a material that has it all – photovoltaic properties, unbelievable strength, flexibility, conductive properties, as well as the capability to sense whatever one may imagine from humidity to pressure, temperature or light. During a keynote speech at this year’s Mobile World Congress in Barcelona, Novoselov described how stacking two-dimensional materials layer by layer could achieve exactly that.
Although graphene is still the one in the spotlight, scientists already have entire libraries of 2D materials similar to graphene that can be used to virtually engineer materials atom by atom to have even more miraculous properties than the wonder material itself.
“There are few materials that determine our world today,” the 41-year old physicist said. “It’s silicon in electronics, aluminium and titanium in aerospace, steel in construction. But these materials limit what we can do. We are now developing what we call heterostructures that would allow us to first design a device and then, atom by atom, to engineer a material that would exactly fit our needs.”
Graphene is a one-atom-thick layer of carbon atoms first isolated in 2004 by Novoselov and his academic supervisor Professor Andre Geim during the ‘Friday evening’ sessions of usually not-so-serious experiments. Graphene has very different properties from its precursor, 3D crystal. The same applies to every other two-dimensional material.
“Combining these two-dimensional crystals, we can design materials that never existed in nature that offer properties that never existed in nature,” Novoselov explained. “With a large number of 2D crystals we have basically an infinite number of functionalities all combined within one stack.”
The manufacturing method for such devices could be staggeringly simple – they could be printed by an inkjet printer from liquid suspensions of the 2D crystals.
At this year’s Mobile World Congress (MWC 2016), in Barcelona, such graphene-based printed electronic devices were demonstrated, including printed RFID tags and touch sensors.
2016 is the first year that a pavilion dedicated to graphene has been presented at MWC, a clear indication that the wonder material is ready for its grand entrance from laboratory to factory floor.
“What we have here at the wireless show today is not only university research but also spin-out companies,” said Ivan Buckley, Graphene Project Manager at the University of Manchester, the professional home of Novoselov and Geim for many years and the place where graphene was born.
“We have companies who have sensor devices, we have companies who have devices for RFID tagging for security purposes, we are showing some of the early super capacitor research.”
The Manchester team presented a graphene-based super capacitor the size of a coin at the show, which could pave the way for the creation of instantly rechargeable super batteries that would enable mobile devices to last considerably longer between recharges.
The university’s graphene light bulb - the first commercially available product made of graphene - was also presented. Already the fourth generation, the extremely energy efficient light bulb has since been developed into an intelligent street light that automatically adjusts to the ambient conditions.
Surprisingly cool to the touch, the light bulb demonstrates further promising properties of graphene for electronics applications - its ability to efficiently dissipate heat.
“At the University of Manchester, we already work with 50 companies,” said Buckley. “Significantly, one of our most recent partners is Huawei, who are looking at how they could dissipate heat away from circuits because circuits will become smaller and smaller and as a result, heat will be a major factor in consideration of the use of smaller circuits.”
According to Cambridge University Professor Andrea Ferrari, graphene will be the enabling material not only for ultra-high-speed 5G wireless data networks, but also for the emerging Internet of Things - mostly due to its small energy consumption coupled with the ability to cater for extreme data speeds. The university hopes to have prototype graphene-based transceivers ready by 2018.
Italian research institute ISOF presented prototype graphene-based wearable touch and strain sensors.
“The goal is to make a wearable device with sensors all based on carbon, particularly on graphene,” said ISOF’s Vincenzo Palermo. “You have printed electronic circuits made of graphene: these can be made by an inkjet printer.”
One can imagine that the first consumer graphene-based gadget to be presented at a future Mobile World Congress expo will be a massive hit. To get there, however, a few obstacles need to resolved. Even though graphene is no longer made the way Geim and Novoselov did it in their pioneering research (using a scotch tape and pencil), current manufacturing methods still don’t allow the full scaling necessary for consumer electronics production.
“One of the major challenges for the industry in the scale-up of graphene for use in mobile devices and screens is the process called chemical vapour deposition,” explained Buckley. “In chemical vapour deposition, graphene is grown on a copper substrate and one of the problems is how to transfer graphene from this copper surface onto another substrate such as PET because you have to remember that it is one atom thick so it can crack, it can crease, it can break very easily.”
The task now, Buckley says, is not that much with scientists but rather with the engineers. Research initiatives such as the Graphene Flagship or the Manchester-based National Graphene Institute hope to encourage companies to delve into the challenges - after that, the researcher says, only the sky is the limit.