Tuesday, November 05, 2013: One of the key components in white LED lighting, phosphors, can be optimised, courtesy a team of researchers, which include one researcher from Indian-origin. This will allow brighter and more efficient lights.
Researchers at University of California – Santa Barbara’s Solid State Lighting & Energy Center (SSLEC) discovered it by determining simple guidelines.
Ram Seshadri, a professor in the university’s Department of Materials as well as in its Department of Chemistry and Biochemistry told Zee News, “These guidelines should permit the discovery of new and improved phosphors in a rational rather than trial-and-error manner.”
The study was conducted in collaboration with materials professor Steven DenBaars and postdoctoral associate researcher, Jakoah Brgoch.
So far phosphor materials were prepared on the basis of finding crystal structures that can act as host to activate ions, which then converts higher-energy blue light to lower-energy yellow/orange light.
“So far, there has been no complete understanding of what make some phosphors efficient and others not. In the wrong hosts, some of the photons are wasted as heat, and an important question is: How do we select the right hosts?” Seshadri said.
Brgoch said, “Very few phosphor materials retain their efficiency at elevated temperatures. There is little understanding of how to choose the host structure for a given activator ion such that the phosphor is efficient, and such that the phosphor efficiency is retained at elevated temperatures.”
This will fast forward the efforts to develop high-efficiency, high-brightness, solid-state lighting.
“Our target is to get to 90 per cent efficiency, or 300 lumens per watt,” said DenBaars. Current incandescent light bulbs, by comparison, are at roughly 5 per cent efficiency, and fluorescent lamps are a little more efficient at about 20 per cent.
“We have already demonstrated up to 60 per cent efficiency in lab demos,” DenBaars said.
