Nanocarbon materials are challenging silicon – from transparent electronics to bendable 3D displays

"Light and flexible nanocarbon materials conduct electricity better than copper and have greater mechanical strength than steel. They are also good thermal conductors and have great potential for use in reinforced composites, nanoelectronics, sensors and nanomechanical devices," says professor Esko I. Kauppinen, the director of Aalto University’s NanoMaterials research group.

Recently, significant advances have been made in the development of nanocarbon materials and their applications. The International Symposium on Nanocarbon Materials gathered the world’s cutting-edge nanocarbon material researchers to Aalto University.

Flexible and transparent electronics

One of the breakthrough applications of carbon nanotubes (CNT) is foreseen in transistor technology. Carbon nanotubes have already been shown to outperform silicon as the semiconducting material for transistors.

"The structure of CNT makes it more chemically stable than silicon. Compared to silicon CMOS technology, carbon nanotube devices are about 5-10 times faster, over 10 times more efficient in power consumption and much smaller in size," says professor Lian-Mao Peng from Peking University.

There are still several technical problems to solve before CNT based chips become commercial products; the main concerns are the material’s thermal and long-term stability. Also, the silicon industry is very mature and it will take major efforts to replace silicon as semiconducting material in electronics.

"I would say in 3-5 years we will see CNTs in some low-end applications that are not dominated by silicon, like flexible and transparent electronics. Maybe in 10-15 years CNT will get to mainstream semiconductor industry with high performance and low power consumption," Peng says.

Carbon nanotube films are also a potential material for the charge selection/conduction layer of perovskite solar cells. Perovskite solar cells challenge the traditional silicon cells with a cheaper, simpler and more energy-efficient manufacturing process.

"The best reported perovskite solar cells have the power conversion efficiency of 22 percent which is compatible to silicon solar cells. And, they can be much cheaper than silicon cells as organic solar cells. Also, flexible and transparent perovskite solar cells could be integrated in windows and other building surfaces. I expect they could become commercial in 3-5 years," says professor Shigeo Maruyama from the University of Tokyo.

Carbon nanostructure such as graphene gets exciting new applications through nanoscale technologies. Photo: Alexander Savin.

Shaping surfaces with curved and 3D formed displays

Besides carbon nanotubes, nanocarbons are found in various structures like spherical fullerens and single atomic layer graphene. In 2006, a new carbon composite nanomaterial was discovered by Aalto University NanoMaterials Group headed by professor Kauppinen. The material was named and patented as NanoBud.

"NanoBuds are formed by binding spheroidal carbon molecules, fullerenes, to the outer sidewalls of single-walled carbon nanotubes. Printed on a thin film of plastic, NanoBuds can be used in touch screens of mobile phones, cameras and wearable devices,"  Kauppinen says.

The discovery of NanoBud led to the establishment of Canatu Oy to develop and exploit commercial innovations. The Aalto University spin-off company manufactures 3D formable, flexible and transparent carbon NanoBud films and touch sensors for consumer electronics and automotive industry.

The NanoMaterials Group is one of the world's leading gas-phase synthesis laboratories for NanoBuds, nanotubes and nanomaterials. In Aalto University, high-level nanocarbon material research is conducted also in several other research teams in the School of Science, School of Chemical Engineering and School of Electrical Engineering.

"Besides our strong international networks, nanocarbon material research collaboration within Aalto University is most fruitful. By learning from each other we can achieve much better results compared to what we could accomplish ourselves," Kauppinen says.

The future of nanocarbon materials shines bright.

The world’s cutting-edge nanocarbon material researchers gathered to Aalto University's Dipoli building in Espoo. Photo: Alexander Savin.