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New material could lead to cheaper, more eco-friendly LEDs

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June 14, 2013

LumiSands founders Chang-Ching Tu (left) and Ji Hoo, demonstrating the warmer hue of an LE...

LumiSands founders Chang-Ching Tu (left) and Ji Hoo, demonstrating the warmer hue of an LED bulb utilizing their technology

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LED light bulbs may be more energy-efficient and longer-lived than their incandescent equivalents, but they’re also considerably more expensive to purchase. This is largely because rare earth elements (REEs) are used in their phosphors. There are hazards involved in the mining and processing of REEs, plus China is responsible for almost the entire world’s supply, so they’re becoming increasingly pricey. Now, however, scientists have come up with a plentiful alternative material that they say is much more environmentally friendly, and that should drive down the price of LEDs.

In regular LED bulbs, the REE-based phosphors are used to soften the LED’s existing blue-ish light. University of Washington spinoff company LumiSands has developed a material that reportedly does the same thing, but that also converts the light to a color temperature closer to that of natural sunlight. What's more, the material is made from cheap, abundant silicon.

The company produces the material by etching nanoparticles from a silicon wafer, then embedding them in an ultra-thin membrane. When subsequently exposed to an LED light source, the nanoparticles glow red. The combination of the LED’s own blue light and the red from the silicon results in a soft, warm sun-like light.

According to LumiSands co-founder and CEO Chang-Ching Tu, the whole process can be performed in a laboratory, and should be easy to scale up for commercial production.

The company is now looking into methods of getting the nanoparticles to fluoresce in additional colors such as yellow and green, for use in LEDs that emit a neutral white light. It is also in the process of seeking industrial partners, and hopes to begin production in no more than a year.

Source: University of Washington

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
5 Comments

Cool, we need to wean ourselves from China's Rare Earth monopoly.

Racqia Dvorak
14th June, 2013 @ 05:41 pm PDT

begin production in no more than a year?? really? I have my doubts but I would love to be proven wrong.

Michael Mantion
15th June, 2013 @ 01:43 am PDT

Like the rapidly dissipating, 70 year lunacy that the 'Arabs have all the oil', the 'Chinese have all the Rare Earth elements' is another silly fiction. Worker wages, worker safety, worker benefits, government corruption, environmental and conservation issues decide where it is cheaper to process these elements. If you are willing to lose 15 miners a day and get away with paying

Robert Walther
15th June, 2013 @ 05:03 am PDT

"Rare Earth" is a persistent misnomer. There was a time when these elements were thought to actually be rare, hence the name. However this stuff is readily available and well enough distributed across the planet that no one nation should have any monopoly. However, much of the world does have environmental safety rules, miner & refiner safety rules and in many places miners earn a decent living. Not true in China. And since many of the important decisions are made by Trans National Corporations the actual mining & refining choices are made where costs are cheapest and where public officials can be bought for the best rent-to-own rates.

Hence, again, China. However, the people of China are beginning to notice the severe degradation of their homes, food, environment, & health.

"Rare Earth" minerals can mined quite nicely in Colorado and the formerly closed mine there should be coming online this year after being dormant for nearly twenty years.

StWils
17th June, 2013 @ 11:35 am PDT

LED's from sand?? BRILLIANT!!!!

rsheng
17th June, 2013 @ 12:11 pm PDT
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