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Potemkin
06-19-2009, 04:32 PM
http://news.cnet.com/8301-17912_3-10268966-72.html?tag=newsLatestHeadlinesArea.0

An LED breakthrough in Korea?


by Candace Lombardi

Researchers from Korea claim to have produced the world's first purely white LED (light-emitting diode).

Soo-Young Park, a professor of organic materials for photonics at the Department of Materials Science and Engineering at Seoul National University in Korea, led the group, which includes researchers from the University of Valencia in Spain.

LEDs are much more energy-efficient than incandescent or compact fluorescent lightng (CFL), but the quality of light they can give a room is up for debate.

Soo-Young Park, professor at Seoul National University.
(Credit: Seoul National University)

Because LEDs do not naturally produce white light, getting them to look like they do adds to their production cost, making them much more expensive than your average incandescent or CFL. Many companies have been trying to come up with different LED recipes and components to produce a nice white light, while keeping the consumer cost down.

Park and his group claim to have engineered a molecule with one orange and one blue light-emitting material that produces a white light in the visible light spectrum when put together.

In other words, they say they've invented a white-light-emitting diode.

Repeated laboratory tests apparently showed that the new form of LED molecule is efficient, color stable, and able to be reproduced again and again, making it a legitimate candidate for use in LED lighting.

A detailed explanation of the group's molecular work can be found in the current issue of Journal of the American Chemical Society.

"An ideal material for a white-light source should be cost-effective, stable, robust, emit over the whole visible spectrum, not suffer from self-absorption, and its pure color should be easily reproducible. With this goal in mind, we have successfully synthesized and characterized, for the first time, a white-light-emitting single molecule dyad, consisting of two noninteracting chromophores showing excited-state intramolecular proton transfer," Park and his group said in their paper.