LEDs could be made from a new, cheaper material, after a new discovery by a US company.
Washington-based LumiSands has developed a silicon quantum dot phosphor (SiQD-phosphor) technology which has the same ability to soften the natural blue-ish light of LEDs, and convert the light to a colour temperature closer to that
of natural sunlight. However the silicon is more abundant and significantly less expensive than the traditional phosphors used in LED fabrication, which use rare earth elements
(REEs).
Other contributory factors in the expense of LEDs are the hazards involved in the
mining and processing of REEs, and the fact that China is responsible for almost the
entire world’s supply of REEs.
LumiSands 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.
The whole
process can be performed in a laboratory, according to LumiSands co-founder and CEO Chang-Ching Tu, and should be easy to scale up
for commercial production.
The company is looking for partners to develop the material, and is investigating methods of enabling the nanoparticles
to fluoresce in additional colors such as yellow and green, for use in
LEDs that emit a neutral white light. Production could begin in less than a year.
