Academics say they have created a material that can make LEDs cheaper to manufacture by removing the need to use expensive rare earth element (REE) phosphors.
The researchers, who work at the University of Washington have developed silicon-based nanoparticles, derived from sand, that can soften the blue light emitted by LEDs, a job usually done by REE phosphors.
The company, LumiSands, which started as a project for the university's electrical engineering students Chang-Ching Tu and Ji Hoo, has managed to separate nano-sized particles from wafers of silicon which then start to glow when the particle size is smaller than five nanometers.
When the red-emitting silicon nanoparticles are added to LEDs, the light becomes softer and warmer in hue. LumiSands plans to tweak the red technology before moving on to other colours such as yellow and green. This will enable LEDs to cast a white light with no rare earth elements.
Chang-Ching Tu, left, and Ji Hoo with a demo showing the warmer, softer hue of the LED (left) after a film embedded with their nanoparticles is placed underneath. The box on the right is an identical, standard LED.
REE phosphors have become increasingly hazardous to extract and process, with China controlling most of the global market. This has led to dramatic increases in the price of REEs in recent years.
"Hopefully, manufacturers could substitute traditional rare earth elements with our material with minimal additional steps," said Ji Hoo, co-founder of LumiSands."
The company plans to sell directly to LED lamp manufacturers that are keen to reduce their reliance on expensive materials. It is finishing a prototype of the technology and sending samples to lighting industry partners for analysis as well as applying for funding. It aims to manufacture its technology within a year.??
LumiSands CEO Chang-Ching Tu said: "The manufacturing process can be performed in a basic laboratory setting and is easy to scale up."
