Swedish and American researchers have succeeded in producing a new type of lighting component that’s inexpensive to produce and can be fully recycled. Using the new super material graphene, the invention as an example could pave the way for glowing wallpaper made entirely of plastic.  The emerging field of “organic” or “plastic” electronics has already brought low-voltage, ultrathin, and energy-efficient lighting and displays to market as organic light-emitting diode (OLED) televisions and displays in cameras and mobile phones.

But these are not fully organic; they usually contain a transparent electrode made of the metal alloy indium tin oxide.  The indium alloy presents a problem because indium is both rare, expensive and is complicated to recycle.

An OLED consists of a light-generating layer of plastic placed between two electrodes, one of which must be transparent. Now researchers at Linköping and Umeå universities, working with American colleagues at the Department of Materials Science and Engineering, Rutgers University, are presenting an alternative to OLEDs, an organic light-emitting electrochemical cell (LEC). It’s inexpensive to produce, and the transparent electrode is made of the carbon material graphene.

Graphene Cathode in a Light Emitting Electrochemical Cell. Click image for the largest view.

The research group is utilizing chemically derived graphene for the transparent cathode in an all-plastic sandwich-structure device.  Using a screen-printable conducting polymer as a partially transparent anode and a micrometer-thick active layer solution-deposited from a blend of a light-emitting polymer and a polymer electrolyte, they’ve demonstrated a light-emitting device based solely on solution-processable carbon-based materials. The results demonstrate that low-voltage, inexpensive, and efficient light-emitting devices can be made without using metals. In other words, electronics can truly be “organic”.

Nathaniel Robinson from Linköping University says, “This is a major step forward in the development of organic lighting components, from both a technological and an environmental perspective. 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.”

All of the new LEC’s parts can be produced using fluid solutions, making it possible to make LECs in a roll-to-roll process such as a printing press in a highly cost-effective way.

Ludvig Edman from Umeå University says, “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.”

The graphene used in the production process 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.

For over 15 years researchers worldwide have been trying to replace the indium tin oxide component.  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 essentially inexhaustible and can be fully recycled, back into a fuel, for example.  A non rare earth metallic mixed device is going to be much less expensive and less of a problem when recycled.

A study paper has been 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.

Well . . . If this scales up commercially those coming generations of TVs might be sandwich built way under an inch thick and much less expensive.  Video could get more pervasive than it already is  – as if that’s possible.  Imagining walls and ceilings that glow sounds interesting, but the sensation is yet to be experienced.

But power consumption should be very low.  To brighten areas where the amibiance isn’t a critical part of the design this invention should get rapid adoption.

On the other hand, the light might be just wonderful.  LED and one hopes this new LEC will be free of the oscillations many of us find annoying in fluorescent lit areas. The lumens per installed area are still to come out, the color temperature and other bits of interest will be topics for development.

Wait . . . Wallpaper?  If the love of my life who has a penchant for wallpaper and changing it finds out . . . Lets hope that the pink spectrum is impossible.  Well, I can hope.


2 Comments so far

  1. Matt Musson on February 11, 2010 6:54 AM

    Sounds like we have found the intersection between lighting and video.

    Is that a good thing?

  2. saeed on June 20, 2012 3:48 AM

    it sounds really attractive. but can you guide me which plastic we a can use here?

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