Linköping and Umeå: graphene-based material for new lighting

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Researchers at Linköping University and Umeå University, in Sweden, and Rutgers, the State University of New Jersey, have developed a new type of lighting material based on graphene, which they say has superior qualities to organic light-emitting diodes (OLEDs). The material is inexpensive to produce and can be fully recycled.

Ultra-thin low-energy OLEDs, consisting of a light-emitting sheet of plastic between two electrodes (one of which must be transparent), have recently been introduced commercially in mobile phones, cameras, and super-thin TVs. But they have drawbacks: they are expensive to produce because the transparent electrode consists of the metal alloy indium tin oxide, which is rare and complicated to recycle.

The researchers at Linköping and Umeå say that in comparison their organic light-emitting electrochemical cell (LEC) is inexpensive to manufacture and the transparent electrode is made of the carbon material graphene.

“This is a major step forward in the development of organic lighting components, from both a technological and an environmental perspective. By using graphene instead of conventional metal electrodes, [lighting] components of the future will be much easier to recycle and thereby environmentally attractive,” said, Nathaniel Robinson from Linköping University, one of the researchers.

Since all the parts for an LEC can be produced from liquid solutions, it will be possible to make LECs in a roll-to-roll process on, for example, a printing press in a highly cost-effective way.

“This paves the way for inexpensive production of entirely plastic-based lighting and display components in the form of large flexible sheets. This kind of illumination or display can be rolled up or can be applied as wallpaper or on ceilings,” says another researcher, Ludvig Edman from Umeå University.

Graphene consists of a single layer of carbon atoms and has many attractive properties as an electronic material. It has high conductivity, is virtually transparent, and can be produced as a solution in the form of graphene oxide.