An LED breakthrough in Korea?
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.
In a software-driven world, it's easy to forget about the nuts and bolts. Whether it's cars, robots, personal gadgetry or industrial machines, Candace Lombardi examines the moving parts that keep our world rotating. A journalist who divides her time between the United States and the United Kingdom, Lombardi has written about technology for the sites of The New York Times, CNET, USA Today, MSN, ZDNet, Silicon.com, and GameSpot. E-mail her at candacelombardi@gmail.com. She is a member of the CNET Blog Network and is not a current employee of CNET. 
See Figure 4c of the paper. Pretty nice. No spikes like in fluorescent bulbs: http://www.bealecorner.org/best/measure/cf-spectrum/index.html
Most CFL's life span are way over rated too. They stated a couple thousand hours of life span, but a few of them gave out after two weeks, then majority of them broke down after a year. It is not worth the time to pursue the warranty of these lights from the manufacturer. If the CFL broke down in a couple of weeks, I'll return it to the stores and get new one rather than deal with the manufacturer. I amazingly have a couple of CFL bulbs that is still working after 10 years of normal day to day use.
LED's would be nice if they can keep the cost down and it would be nice if the manufacturers can show us the realistic statistical average life span of the final product in a given context like normal household usage. So far, all that marvelous quotes of very long lifespan are THEORETICAL limits and not based on actual or realistic tests.
exactly! <sarcasm>
looks like it's worked on you as well...
- by 21447krauter1 July 9, 2009 5:19 AM PDT
- The comments about inferior LEDs are reckless to some products in this industry. If you buy a Costco or other box store product look at the warranty, the compliance with UL Listing and the DOE standards LM 79 and LM 80. And most of all look at the origin of the product, China has flooded the market with a questionable products. There are alternatives that are truly superior to CFLs and incandescent but it takes a bit of research.
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- by sslPro July 30, 2009 6:37 PM PDT
- you have a good grasp on the reality- costco garbage is like a yugo IT REALLY IS CRAP AND IS
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(16 Comments)DAMAGING MY INDUSTRY- I am a mfg rep for the premier SSL concern - It is crucial to have standards in
place such as caliper and Independant Testing Labs data to set standards. Yes garbage is out there and it's
buyer be informed - But there are examples of Quality Leds like Borealis or cree lighting .The quality
is based on the Led itself( Nichia/cree)and thermal mgmt , the driver ,the construct and architechure
And quality of optics, and if a mfg promises a 1 year or 5 year guarantee do they have a record of honoring it?
A 5 year iron clad warranty rarely invoked is the right scenario ( and these lights are made in Illinios(except chip)
People want & deserve quality- Reseach ,switch to quality and get an energy audit /improve our bldgs now!!
A CHAIN IS ONLY AS STRONG AS THE WEAKEST LINK