A team led by engineers at the University of California San Diego has used data mining and computational tools to discover a new phosphor material for white LEDs that is inexpensive and easy to make. Researchers built prototype white LED light bulbs using the new phosphor. The prototypes exhibited better color quality than many commercial LEDs currently on the market.
Researchers published the new phosphor on Feb. 19 in the journal Joule.
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.
Researchers at UC San Diego and Chonnam National University in Korea discovered and developed a new phosphor that avoids these issues. It is made mostly of earth-abundant elements (strontium, lithium, aluminum and oxygen); it can be made using industrial methods; and it produces LEDs that render colors more vividly and accurately.
The new phosphor, Sr2LiAlO4 or simply 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.
Researchers in the lab of Joanna McKittrick, a materials science professor at the Jacobs School of Engineering, then figured out the recipe needed to make the new phosphor. They also confirmed the phosphor’s predicted light absorption and emission properties in the lab.
A team led by materials science professor Won Bin Im at Chonnam National University in Korea optimized the phosphor recipe for industrial manufacturing and built white LED prototypes with the new phosphor. They evaluated the LEDs using the Color Rendering Index (CRI), a scale that rates from 0 to 100 how accurate colors appear under a light source. Many commercial LEDs have CRI values at around 80. LEDs made with the new phosphor yielded CRI values greater than 90.
The Computational Quest for a New Material
Thanks to the computational approach developed by Ong’s team, discovery of the phosphor took just three months—a short time frame compared to the years of trial-and-error experiments it typically takes to discover a new material.
“Calculations are quick, scalable and cheap. Using computers, we can rapidly screen thousands of materials and predict candidates for new materials that have not yet been discovered,” Ong said.
Ong, who leads the Materials Virtual Lab and is a faculty member in the Sustainable Power and Energy Center at UC San Diego, uses a combination of high-throughput calculations and machine learning to discover next-generation materials for energy applications, including batteries, fuel cells and LEDs. The calculations were performed using the National Science Foundation’s Extreme Science and Engineering Discovery Environment at the San Diego Supercomputer Center.
In this study, Ong’s team first compiled a list of the most frequently occurring elements in known phosphor materials. To the researchers’ surprise, they found that there are no known materials containing a combination of strontium, lithium, aluminum and oxygen, which are four common phosphor elements. Using a data mining algorithm, they created new phosphor candidates containing these elements and performed a series of first-principles calculations to predict which would perform well as a phosphor. Out of 918 candidates, SLAO emerged as the leading material. It was predicted to be stable and exhibit excellent photoluminescence properties.
“It’s not only remarkable that we were able to predict a new phosphor compound, but one that’s stable and can actually be synthesized in the lab,” said Zhenbin Wang, a nanoengineering Ph.D. candidate in Ong’s research group and co-first author of the study.
The phosphor’s main limitation is its less than ideal quantum efficiency—how efficiently it converts incoming light to light of a different color—of about 32 percent. However, researchers note that it retains more than 88 percent of its emission at typical LED operating temperatures. In commercial LEDs, there’s usually a tradeoff with color quality, Ong noted. “But we want the best of both worlds. We have achieved excellent color quality. Now we are working on optimizing the material to improve quantum efficiency,” Ong said.
The Latest on: Predicting new materials
via Google News
The Latest on: Predicting new materials
- Polkadot Price Prediction: DOT aims for a bullish reversal to new all-time highson February 25, 2021 at 4:49 am
DOT faces only one critical resistance level before a massive 30% breakout. Polkadot bulls seem to have the upper hand after establishing a higher low. Polkadot had a significant correction from its ...
- Daily Horoscope for February 26 Astrological Prediction for Zodiac Signson February 25, 2021 at 4:46 am
The moon squares Mars around sunrise, so don’t take anything too personally. The odds of someone raising their voice today is high (hopefully not you).Daily Planetary Overview Before most of us are ev ...
- Cryptocurrencies Price Prediction: Bitcoin, Bitcoin SV and Stellar Lumens – European Wrap 25 Februaryon February 25, 2021 at 4:05 am
Bitcoin SV price has seen massive spikes in buying pressure followed by equally extreme selling pressure. Now, BSV stands at a make-or-break point as the main figure behind the project faces another ...
- 3-Methylpyridines Market Future Prediction Report 2022-2031 | Vertellus and LONSAon February 25, 2021 at 4:04 am
A recent systematic review report on “3-Methylpyridines Market Outlook With New Entrants Feasibility & Regional Forecast 2031 | Changing the Face of Chemicals and Materials Industry”, came out Market.
- Pfizer and BioNTech Initiate a Study as Part of Broad Development Plan to Evaluate COVID-19 Booster and New Vaccine Variantson February 25, 2021 at 3:49 am
Pfizer Inc. (NYSE: PFE) and BioNTech SE (Nasdaq: BNTX) announced today they have begun an evaluation of the safety and immunogenicity of a third dose of the Pfizer-BioNTech COVID-19 vaccine (BNT162b2) ...
- Generalization of intrinsic ductile-to-brittle criteria by Pugh and Pettifor for materials with a cubic crystal structureon February 25, 2021 at 2:53 am
Two classical criteria, by Pugh and Pettifor, have been widely used by metallurgists to predict whether a material will be brittle or ductile. A phenomenological correlation by Pugh between metal ...
- Basalt Town Council approves new design for east entrance signon February 25, 2021 at 1:00 am
This has been dragging on and on and on as these signs seem to do,” Lynne Mace, a member of the Basalt Chamber Sign Committee, said during Tuesday’s council meeting. On Tuesday, the Basalt Town ...
- Engineering Services Market Growth Analysis, Competitive Landscape Outlook and COVID-19 Impact Prediction 2025on February 24, 2021 at 11:58 pm
New year, new updates! Our reports have been revised for market ... and utilization of machines, materials, instruments, structures, processes, and systems. Engineering services include the technical ...
- Global Injectable Anesthetics Market 2020 Growth Parameters, Competitive Landscape Outlook and COVID-19 Impact Prediction 2025on February 24, 2021 at 12:25 pm
The recently uploaded report titled Global Injectable Anesthetics Market 2020 by Manufacturers, Type and Application, Forecast to 2025 delivers detailed information on the industry including ...
- New action on horizon for sustainable materials management under Biden, experts predicton February 17, 2021 at 7:54 am
Recycling market development and food waste are among many issues stakeholders hope will receive renewed federal engagement, despite limited attention in the president's agenda to date.
via Bing News