Cheaper LEDs

Computers have helped researchers develop a new phosphor that can make LEDs cheaper and render colors more accurately. Researchers predicted the new phosphor using supercomputers and data mining algorithms, then developed a simple recipe to make it in the lab. Unlike many phosphors, this one is made of inexpensive, earth-abundant elements and can easily be made using industrial methods. As computers predicted, the new phosphor performed well in tests and in LED prototypes.


Credit: David Baillot/Uc San Diego Jacobs School Of Engineering

Phosphors, which are substances that emit light, are one of the key ingredients to make white LEDs. They are crystalline powders that absorb energy from blue or near-UV light and emit light in the visible spectrum. The combination of the different colored light creates white light. The phosphors used in many commercial white LEDs have several disadvantages, however. Many are made of rare-earth elements, which are expensive, and some are difficult to manufacture. They also produce LEDs with poor color quality.

The new phosphor — made of the elements strontium, lithium, aluminum and oxygen (a combination dubbed “SLAO”) — was discovered using a systematic, high-throughput computational approach developed in the lab of Shyue Ping Ong, a nanoengineering professor at the UC San Diego Jacobs School of Engineering and lead principal investigator of the study. Ong’s team used supercomputers to predict SLAO, which is the first known material made of the elements strontium, lithium, aluminum and oxygen. Calculations also predicted this material would be stable and perform well as an LED phosphor. For example, it was predicted to absorb light in the near-UV and blue region and have high photoluminescence, which is the material’s ability to emit light when excited by a higher energy light source.

Source (University of California – San Diego. “Computers aid discovery of new, inexpensive material to make LEDs with high color quality.” ScienceDaily. ScienceDaily, 19 February 2018.)

Original paper: Wang, Z., Ha, J., Kim, Y.H., Im, W.B., McKittrick, J. and Ong, S.P., 2018. Mining unexplored chemistries for phosphors for high-color-quality white-light-emitting diodes. Joule2(5), pp.914-926.