An organic light-emitting electrochemical cell (LEC) could be a cheaper alternative to OLED technology thanks to work from researchers at Linköping University and Umeå University, in Sweden, and Rutgers, The State University of New Jersey. It is inexpensive to produce, and the transparent electrode is made of the carbon material graphene rather than the expensive indium tin oxide - indium being both rare, expensive and complicated to recycle.
"Organic electronics components promise to become extremely common in exciting new applications in the future, but this can create major recycling problems. By using graphene instead of conventional metal electrodes, components of the future will be much easier to recycle and thereby environmentally attractive," says one of the scientists, Nathaniel Robinson from Linköping University.
Since all the LEC's parts can be produced from liquid solutions, it will also be possible to make LECs in a roll-to-roll process on, for example, a printing press in a highly cost-effective way.
The researchers believe this could pave the way for low cost plastic based lighting and display components in the form of large flexible sheets that can be rolled and used as illuminating wallpaper.
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 moreover be produced as a solution in the form of graphene oxide.
Researchers all over the world have been trying to replace indium tin oxide for more than 15 years. Indium is in short supply, and the alloy has a complicated life cycle. The raw material for the fully organic and metal-free LEC, on the other hand, is inexhaustible and can be fully recycled - as fuel, for example.
The study is published in the journal ACS Nano and is titled "Graphene and mobile ions: the key to all-plastic, solution-processed light-emitting devices." The authors are Piotr Matyba, Hisato Yamaguchi, Goki Eda, Manish Chhowalla, Ludvig Edman, and Nathaniel D. Robinson.
For more attend Printed Electronics Europe 2010.