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
- Daily Deals: LG OLED 4K TV For $897, New Version Nintendo Switch for $299, Apple Watch Series 4 for $479 and Moreon August 17, 2019 at 10:29 am
OLED TVs are still considered the TV to buy if you want the ... old and is still easily the best tablet you can buy for under $300. It boasts a 9.7" Retina display, A10 Fusion 64-bit processor, dual ...
- Apple Watch Series 5 to use OLED displayon August 17, 2019 at 7:36 am
San Francisco: Apple Watch Series 5 model is expected to use OLED screens supplied by Japan Display, according to analyst Ming-Chi Kuo. According to Kuo, Japan Display would gradually increase its ...
- 100 off Apple iPad 128GB only $320; $300 off LG's 65" OLED C9 HDTV, Nintendo Switch, Galaxy Note 10 pre-orderson August 17, 2019 at 7:07 am
Apple MacBook Air 8th Gen Intel Core i5 13.3" 2560x1600 Retina Display Laptop with 128GB SSD for $949.99 at ... LG G8 ThinQ 128GB Octa-Core 6.1" QHD+ OLED Unlocked Smartphone for $499.99 at Amazon ...
- Apple Watch Series 5 will reportedly still have OLED displayson August 17, 2019 at 6:30 am
The Apple Watch 4 launched last year. Apple's next-generation smartwatch is reportedly launching in the fall and will retain its OLED displays, with Japan Display tipped to be the supplier. The Apple ...
- Apple Watch Series 5 to feature OLED displayon August 17, 2019 at 4:24 am
Apple Watch Series 5 model is expected to use OLED screens supplied by Japan Display, according to analyst Ming-Chi Kuo. According to Kuo, Japan Display would gradually increase its proportion of OLED ...
- Apple iPhone 11 to use same OLED display as Galaxy S10, Note 10on August 17, 2019 at 4:11 am
Apple iPhone 11 will reportedly come with the same OLED displays used for Samsung’s Galaxy S10 and Note 10. The move is likely to assist Samsung Display in a number of ways, including reducing the ...
- iPhone 11 to use same OLED display as Galaxy S10, Note 10on August 16, 2019 at 8:19 pm
Apple iPhone 11 will reportedly come with the same OLED displays used for Samsung's Galaxy S10 and Note 10.IANS | August 17, 2019, 08:49 IST San Francisco, Apple iPhone 11 will reportedly come ...
- Friday Apple Rumors: Japan Display May Supply OLED for Watch Series 5on August 16, 2019 at 4:09 pm
Leading the Apple (NASDAQ:AAPL) rumor mill today is news of the Watch Series 5. Today, we’ll look at that and other Apple Rumors for Friday. Source: Anna Hoychuk / Shutterstock.com Watch Series ...
- Report: iPhone 11 to use same OLED display materials as Samsung Galaxy S10 and Note 10on August 15, 2019 at 12:22 pm
According to a South Korea industry report, Apple is set to use the same OLED display panel materials for the iPhone 11 as is found in the Samsung Galaxy S10 and the Galaxy Note 10. For the iPhone ...
- Fitbit Versa 2 leaks point to September 15 release, confirm Alexa integration and OLED displayon August 15, 2019 at 4:07 am
Notice a bug? Let us know here.
via Bing News