“People once believed that this family of organic light-emitting molecules was restricted to a small region of molecular space,” said Harvard Professor Alán Aspuru-Guzik, pictured. “But, by developing a sophisticated molecular builder, we discovered a large set of high-performing blue OLED materials.”
The team began by building libraries of more than 1.6million candidate molecules, after which machine learning algorithms predicted which molecules were likely to have good outcomes.
“We were able to model these molecules in a way that was really predictive,” said researcher Rafael Gómez-Bombarelli. “We could predict the colour and the brightness of the molecules from a simple quantum chemical calculation and about 12 hours of computing per molecule.”
“Molecules are like athletes,” Prof Aspuru-Guzik added. “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.”
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.
According to the researchers, this type of molecular screening could have broader application. “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 Prof Aspuru-Guzik. “The future of accelerated molecular design is really, really exciting.”