Swedish and American researchers have developed what they claim is a cheaper alternative to the organic light-emitting diode (OLED). The new product, an organic light-emitting electrochemical cell (LEC), is made from graphene, a carbon-based material which can be fully recycled.

The scientists say the invention paves the way for glowing wallpaper made entirely of plastic.

Ultra-thin OLEDs, now being deployed in mobile phones, cameras, and TVs, have two drawbacks – they are relatively expensive to produce contain the metal alloy indium tin oxide. This presents a problem not only because indium is rare and expensive, but also because it is complicated to recycle.

Now researchers at Linköping and Umeå universities in Sweden, working with American colleagues, have used graphene to make LECs, which being based on carbon are low-cost to manufacture and easy to recycle.

“This is a major step forward in the development of organic lighting components, from both a technological and an environmental perspective. [….] Using graphene instead of conventional metal electrodes, [means] components of the future will be much easier to recycle,” says one of the scientists, Nathaniel Robinson from Linköping University.

And since all the constituent parts of LECs can be produced from liquid solutions, it will be possible to make LECs in a roll-to-roll process on a printing press, for example.

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

Graphene consists of a single layer of carbon atoms, and has many virtues as a material for electronic components, having high conductivity and being virtually transparent.

LECs are described in a paper in ACS Nano: “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.
http://pubs.acs.org/doi/abs/10.1021/nn9018569