New molecules promise cheaper, more efficient OLED displays
Harvard University researchers have designed more than 1,000 new blue-light emitting molecules for organic light-emitting diodes (OLEDs) that could dramatically improve displays for televisions, phones, tablets and more.
OLED screens use organic molecules that emit light when an electric current is applied. Unlike ubiquitous liquid crystal displays (LCDs), OLED screens don’t require a backlight, meaning the display can be as thin and flexible as a sheet of plastic. Individual pixels can be switched on or entirely off, dramatically improving the screen’s color contrast and energy consumption. OLEDs are already replacing LCDs in high-end consumer devices but a lack of stable and efficient blue materials has made them less competitive in large displays such as televisions.
The interdisciplinary team of Harvard researchers, in collaboration with MIT and Samsung, developed a large-scale, computer-driven screening process, called the Molecular Space Shuttle, that incorporates theoretical and experimental chemistry, machine learning and cheminformatics to quickly identify new OLED molecules that perform as well as, or better than, industry standards.
“People once believed that this family of organic light-emitting molecules was restricted to a small region of molecular space,” said Alán Aspuru-Guzik, Professor of Chemistry and Chemical Biology, who led the research. “But by developing a sophisticated molecular builder, using state-of-the art machine learning, and drawing on the expertise of experimentalists, we discovered a large set of high-performing blue OLED materials.”
The research is described in the current issue of Nature Materials.
The biggest challenge in manufacturing affordable OLEDs is emission of the color blue.
Like LCDs, OLEDs rely on green, red and blue subpixels to produce every color on screen. But it has been difficult to find organic molecules that efficiently emit blue light. To improve efficiency, OLED producers have created organometallic molecules with expensive transition metals like iridium to enhance the molecule through phosphorescence. This solution is expensive and it has yet to achieve a stable blue color.
Aspuru-Guzik and his team sought to replace these organometallic systems with entirely organic molecules.
The team began by building libraries of more than 1.6 million candidate molecules. Then, to narrow the field, a team of researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), led by Ryan Adams, Assistant Professor of Computer Science, developed new machine learning algorithms to predict which molecules were likely to have good outcomes, and prioritize those to be virtually tested. This effectively reduced the computational cost of the search by at least a factor of ten.
“This was a natural collaboration between chemistry and machine learning,” said David Duvenaud, a postdoctoral fellow in the Adams lab and coauthor of the paper. “Since the early stages of our chemical design process starts with millions of possible candidates, there’s no way for a human to evaluate and prioritize all of them. So, we used neural networks to quickly prioritize the candidates based on all the molecules already evaluated.”
“Machine learning tools are really coming of age and starting to see applications in a lot of scientific domains,” said Adams. “This collaboration was a wonderful opportunity to push the state of the art in computer science, while also developing completely new materials with many practical applications. It was incredibly rewarding to see these designs go from machine learning predictions to devices that you can hold in your hand.”
“We were able to model these molecules in a way that was really predictive,” said Rafael Gómez-Bombarelli, a postdoctoral fellow in the Aspuru-Guzik lab and first author of the paper. “We could predict the color and the brightness of the molecules from a simple quantum chemical calculation and about 12 hours of computing per molecule. We were charting chemical space and finding the frontier of what a molecule can do by running virtual experiments.”
“Molecules are like athletes,” Aspuru-Guzik said. “It’s easy to find a runner, it’s easy to find a swimmer, it’s easy to find a cyclist but it’s hard to find all three. Our molecules have to be triathletes. They have to be blue, stable and bright.”
But finding these super molecules takes more than computing power — it takes human intuition, said Tim Hirzel, a senior software engineer in the Department of Chemistry and Chemical Biology and coauthor of the paper.
To help bridge the gap between theoretical modeling and experimental practice, Hirzel and the team built a web application for collaborators to explore the results of more than half a million quantum chemistry simulations.
Every month, Gómez-Bombarelli and coauthor Jorge Aguilera-Iparraguirre, also a postdoctoral fellow in the Aspuru-Guzik lab, selected the most promising molecules and used their software to create “baseball cards,” profiles containing important information about each molecule. This process identified 2500 molecules worth a closer look. The team’s experimental collaborators at Samsung and MIT then voted on which molecules were most promising for application. The team nicknamed the voting tool “molecular Tinder” after the popular online dating app.
“We facilitated the social aspect of the science in a very deliberate way,” said Hirzel.
“The computer models do a lot but the spark of genius is still coming from people,” said Gómez-Bombarelli.
“The success of this effort stems from its multidisciplinary nature,” said Aspuru-Guzik. “Our collaborators at MIT and Samsung provided critical feedback regarding the requirements for the molecular structures.”
“The high throughput screening technique pioneered by the Harvard team significantly reduced the need for synthesis, experimental characterization, and optimization,” said Marc Baldo, Professor of Electrical Engineering and Computer Science at MIT and coauthor of the paper. “It shows the industry how to advance OLED technology faster and more efficiently.”
After this accelerated design cycle, the team was left with hundreds of molecules that perform as well as, if not better than, state-of-the-art metal-free OLEDs.
Applications of this type of molecular screening also extend far beyond OLEDs.
“This research is an intermediate stop in a trajectory towards more and more advanced organic molecules that could be used in flow batteries, solar cells, organic lasers, and more,” said Aspuru-Guzik. “The future of accelerated molecular design is really, really exciting.”
Learn more: Towards a better screen
The Latest on: OLED displays
via Google News
The Latest on: OLED displays
- LG is price-slashing 2022 OLED TVs at Best Buyon September 24, 2022 at 10:57 am
At Best Buy, a host of LG electronics are seeing a discount through Saturday. This includes a few of its 2022 OLED TVs, some of which have received bigger price drops than I’ve seen occur before.
- Koshinski Asset Management Inc. Has $248,000 Stake in Universal Display Co. (NASDAQ:OLED)on September 24, 2022 at 3:14 am
Koshinski Asset Management Inc. decreased its holdings in Universal Display Co. (NASDAQ:OLED – Get Rating) by 69.3% in the 2nd quarter, according to its most recent filing with the Securities & ...
- Universal Display Co. (NASDAQ:OLED) Shares Bought by Mirae Asset Global Investments Co. Ltd.on September 24, 2022 at 1:24 am
Mirae Asset Global Investments Co. Ltd. raised its position in Universal Display Co. (NASDAQ:OLED – Get Rating) by 21.6% in the 1st quarter, according to its most recent Form 13F filing with the ...
- Best Buy OLED TV deals just dropped this Sony Bravia below $800on September 23, 2022 at 9:10 am
With a 48-inch screen, the Sony Bravia A9S OLED TV isn't the biggest of TVs by any means but if you have a small living room or you're looking for one of the best OLED TVs to add to your gaming den, ...
- HP Pavilion Plus Laptop (14-inch) Review: Budget OLED Beautyon September 23, 2022 at 4:00 am
It's hard to believe the HP Pavilion Plus is under $800, yet well configured with an OLED display. Too bad about the battery life, though.
- Sony made its OLED display into a speaker to take TV audio to a whole new levelon September 22, 2022 at 5:00 pm
Behind the OLED panel are four actuators which cause the screen to vibrate imperceptibly, emitting sound waves. The subwoofer, meanwhile, is built into the easel stand hidden behind the display ...
- Making OLED Displays In The Home Labon September 22, 2022 at 5:00 pm
We’d say that making your own OLED displays at home definitely falls into that category. Of course, the making of organic light-emitting diodes requires more than just a rare-earth metal ...
- The cheapest OLED TV deals and sales for September 2022on September 21, 2022 at 11:26 am
We're rounding up all the best and brightest OLED TV deals from across the web right here, so that you can save on your next investment. These displays often come with a considerable premium ...
- How To Enable Always-On Display On iPhone With This iOS Trickon September 21, 2022 at 5:02 am
Most iPhones don't have an always-on display, but this simple trick provides a workaround to enable the feature on iPhones with OLED displays.
- LED & OLED Displays and Lighting Product Market 2022 Regional Insights and Future Opportunities by 2028on September 20, 2022 at 1:07 pm
The LED & OLED Displays and Lighting Product market research study's bases are its fundamental data and market growth prospects. The study also considers several additional characteristics, such as ...
via Bing News