A New Light

Wired to a small battery, the two-and-a-half-centimeter patch of plastic at General Electric’s research center in Niskayuna, NY, gives off a soft white light. A version of this material could one day form large glowing sheets with the same long life as fluorescent lights but requiring less electricity. Indeed, this patch could represent the future of indoor lighting.

“You are not talking about a light bulb,” says chemist Anil Duggal, manager of GE’s light energy conversion program. “This stuff will be like wallpaper.” The material is made up of organic light-emitting diodes-layers of organic materials that could be fabricated in sheets that are both thin and flexible. Apply electricity and the sheet produces a soft, steady glow. Other companies use organic light-emitting diodes in thin computer displays (see “A Bright Future for Displays,” TR April 2001), but making a material appropriate for lighting homes required the development of diodes that emitted white light. Last fall, Duggal accomplished that by overlaying a bluish-colored diode with a phosphor that transformed the blue light into white.

Philips Lighting, Osram Sylvania and others are also developing white organic light-emitting diodes. But GE seems to lead the pack, says Jim Brodrick, program manager for efficient lighting technologies at the U.S. Department of Energy: “The GE prototype is the most efficient that we are aware of.” While the material now uses 25 times more power for its light output than fluorescent bulbs, Duggal says organic light-emitting diodes’ efficiency could ultimately surpass that of fluorescent lighting.

The lighting sheets could also have advantages over their technological cousins, light-emitting diodes (LEDs). Made of inorganic materials, LEDs flash in stoplights and car headlights. Some companies are investigating their use in general-purpose lighting, but the soft light of organic light-emitting diodes is better suited to a living room than the glaring beams of LEDs, says Brodrick. More important, the organic technology is amenable to mass manufacture through a printing technique, which is potentially far cheaper than the chip fabrication methods required for LEDs.

It could take a decade before GE’s glowing material reaches the interior-lighting market, though products like flexible signs or billboards could come sooner. “The lighting industry as a whole-the market, the customers-is extremely lethargic in terms of new-technology adoption,” says Bill Ryan, group product manager for LEDs at Philips Lighting in Somerset, NJ. “But this area clearly has the potential for being a disruptive technology.” If it reaches its potential, it could eventually mean lights out for century-old incandescent technology.