New material could drive down cost of leds

A spin off from the University of Washington has created a material which it believes could make led bulbs cheaper and greener to manufacture, driving down the price.

While led light bulbs are more energy efficient than standard incandescent or fluorescent bulbs, they're also considerably more expensive to purchase.

This is partly because within each led lamp, expensive substances known as rare earth element phosphors help to soften the harsh blue light that leds naturally emit. In addition, China controls nearly all of the market for these materials, so they're becoming increasingly pricey.

Now, however, University of Washington spin off LumiSands has developed a material that reportedly does the same thing, but also converts the light to a colour temperature closer to that of natural sunlight. What's more, the material is made from cheap, abundant silicon.

"Hopefully, manufacturers could substitute traditional rare earth elements with our material with minimal additional steps," said Ji Hoo, a doctoral student in electrical engineering and co founder of LumiSands. "It will mean cheaper, better quality lighting for users."

LumiSands created the material by etching nanoparticles from a silicon wafer and embedding them in an ultra thin membrane. When exposed to an led light source, the nanoparticles glow red. When the red-emitting nanoparticles are added to led bulbs, the light is said to become softer and warmer in hue, more akin to that of natural sunlight.

LumiSands plans to tweak the red technology before moving on to other colours, such as yellow and green. According to Tu, the manufacturing process can be performed in a basic laboratory setting and is easy to scale up.