New molecules found in research, low-cost OLEDs are expected in the future

Issuing time：2019-12-18

     Researchers at Harvard University have designed more than 1,000 blue light molecules that can significantly improve the display efficiency of OLED TVs, smartphones, and tablets when used in OLEDs.

     Researchers such as Harvard University use machine learning methods to screen blue light OLED molecules that may be used. It is expected that low-cost OLEDs will be realized in the future.

     OLED screens use light-emitting organic molecules that emit light when current is passed through them. Unlike common liquid crystals, OLED screens do not require a backlight device, which means that OLED display devices are thin and flexible, as simple as a plastic sheet. Each pixel on the OLED display can be turned on and off independently, greatly improving screen color contrast and energy efficiency. In high-end consumer products, OLEDs are gradually replacing LCDs, but the low stability of OLEDs and insufficient blue light materials have also caused OLEDs to lose competitiveness in large-scale displays such as televisions.

     A multi-disciplinary team of Harvard researchers working with MIT and Samsung to develop a large-scale, computer-controlled screening process, which they call "Molecular Space Shuttle," adding chemical processes and machine learning at the R & D stage Cheminformatics to quickly find new OLED molecules that meet or exceed industry standards.

     Professor Alán Aspuru-Guzik of the Department of Chemical Biology said: "It is generally believed that the atoms of OLEDs are limited to a very small area of molecular space. Researchers' expertise we have found a significant portion of high-efficiency blue OLED raw materials. "

The biggest challenge is to produce cost-effective blue OLEDs.

    Like liquid crystal technology, OLEDs use green, red, and blue subpixels to make the colors visible to the naked eye on all screens. But it has always been difficult to produce OLEDs that emit blue light. In order to improve efficiency, OLED manufacturers have produced organometallic complex molecules, which use noble metals such as iridium for conversion to strengthen the molecules with phosphorescence.

     This production is expensive and still fails to achieve a stable OLED blue light effect.

    SpAspuru-Guzik and his team are looking for alternatives to these organometallic complex systems, hoping to achieve the complete use of organic molecules only.

    The research team started by creating a molecular database of more than 1.6 billion years ago, and gradually narrowed its scope. The Harvard John Paulson School of Engineering and Applied Science research team led by Ryan Adams, an assistant professor in the Department of Information Engineering, has developed a new machine learning algorithm that can predict which molecules may produce useful results and prioritize These molecules are tested. This initiative drastically reduces the computational cost of research.

     This method of screening atoms can not only be applied to OLEDs.

     Professor Aspuru-Guzil said: "This research is just a relay point in order to stimulate more high-order organic atoms to be used in flow batteries, solar cells, organic lasers and more. The design of accelerated molecular dynamics The future development is exciting. "

    This research was sponsored by Samsung Advanced Technology Research Institute.