For the first time, researchers have experimentally observed light emission from individual graphene nanoribbons. They demonstrated that 7-atom-wide nanoribbons emit light at a high intensity that is comparable to bright light-emitting devices made from carbon nanotubes, and that the color can be tuned by adjusting the voltage. The findings may one day lead to the development of bright graphene-based light sources.
The researchers, led by Deborah Prezzi at the CNR-Nanoscience Institute in Modena, Italy, and Guillaume Schull at the University of Strasbourg in France, have published a paper on their observations of the first electroluminescence from individual graphene nanoribbons in a recent issue of Nano Letters.
“Generally, molecular-scale devices are interesting fundamental systems, but are rather unstable and produce limited amount of signal,” Schull told Phys.org. “In our article, we prove that individual graphene nanoribbons may be used as intense, stable and controllable light sources. These are decisive steps towards real-world optoelectronic applications with nanoscale organic systems.”
Although graphene’s excellent electronic properties have been investigated extensively, much less is known about its optical properties. One of the drawbacks of using graphene as a light-emitting device is that graphene sheets do not have an optical band gap. However, recent studies have shown that, when cut into thin ribbons just a few atoms wide, graphene obtains a sizable optical band gap, opening up the possibility of light emission.