Oct 26, 2010
CNTs bridge gaps to improve transparent flexible graphene electrodes
Graphene, layers of carbon of monatomic thickness, has high conductivity, mechanical strength and flexibility, which makes it a useful material for plastic electronics. Heeyeop Chae's group at Sungkyunkwan University (SKKU), Korea, has developed a new process to obtain high-quality graphene using microwave irradiated expansion. The method is a solution process, which is facile, inexpensive and potentially suits large-scale production. When graphite intercalation compounds are irradiated in a microwave oven, molecular interactions result in uniform heating throughout the sample within a short processing time and bring enhanced expansion with high graphene yield.
Transparent electrodes made of graphene by a solution process have the potential to be applied in electronics at low cost. However, when a thin film is fabricated with microscale graphene sheets, unconnected boundaries can occur between flakes, which results in high sheet resistances.
To enhance the conductivity of the film, the group uses carbon nanotubes (CNTs) to bridge the gaps, as shown in the conceptual diagram above. High-performance conductive films having a resistance of 181 Ωsq–1 and a transmittance of 82.2% were fabricated after chemical treatment and doping.
The fabrication of flexible optical electronic devices such as OLEDs and solar cells is ongoing in Heeyeop Chae's group. "We are keen to develop this novel electrode material for organic and flexible electronic devices and further results will be published soon," Heeyeop Chae told nanotechweb.org.
More details can be found in the journal Nanotechnology.
About the author
Guoqing Xin is an MS candidate in Prof. Heeyeop Chae's group at Sungkyunkwan Univeristy (SKKU), Korea. He is currently exploring flexible OLEDs with graphene electrodes and the optical properties of graphene.