New flexible OLED display technology can be stretched to twice its size

While it would be a bit of a stretch to refer to the newly created material a display, it represents a new technology that could possibly be used to develop stretchable fabric-like displays in the future.

“The materials currently used in these state-of-the-art OLED displays are very brittle; they don’t have any stretchability. Our goal was to create something that maintained the electroluminescence of OLED but with stretchable polymers,” said Sihong Wang, co-author of the research article, in a press statement.

Wang, who is an assistant professor of molecular engineering at the University of Chicago, led the research with Juan de Pablo, who is a professor of molecular engineering at the institute.

“This is the class of material you need to finally be able to develop truly flexible screens. This work is really foundational and I expect it to allow many technologies that we haven’t even thought of yet,” added de Pablo in a statement.

Most high-end smartphones like the iPhone 14 Pro or the Galaxy S23 Ultra use organic light-emitting diode, or OLED technology to power their screens. In OLED displays, small organic molecules are sandwiched between electrical conductors. When current is switched on, the molecules emit a bright light.

Arrange enough of these molecules and conductors in the right way, and you get an OLED display. Such OLED displays are more energy efficient than older LED and LCD technologies and are also known for the picture quality they provide.

Our design strategy of inserting flexible, linear units into polymer backbones can greatly increase stretchability without affecting light-emitting performance. Thereby, an OLED efficiency of 10% is realized, which is on the same order of magnitude as commercial OLEDs. pic.twitter.com/bLVjGwIEQS

— Sihong Wang (@SihongWang_UChi) April 6, 2023

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But according to Wang, the materials that are currently used in OLED displays are very brittle and are not very stretchable. With this in mind, the researchers set out to create a material that maintained the light-emitting properties of OLED but was also stretchable.

“We have been able to develop atomic models of the new polymers of interest and, with these models, we simulated what happens to these molecules when you pull on them and try to bend them. Now that we understand these properties at a molecular level, we have a framework to engineer new materials where flexibility and luminescence are optimized,” said de Pablo.

Using computational predictions for stretchable light-emitting polymers, they built many different prototypes. Just as the computer models they used had predicted, the new materials were flexible, bright, durable and energy efficient, according to the University.

Apart from being used to display information, such a flexible material could be integrated into wearable sensors that need light to work. For example, smartwatches shine a light through blood vessels to measure heart rate and blood oxygenation.

But that could still be a long way ahead. Now, the researchers are focused on improving the device, starting with adding additional colours while also improving its efficiency and performance.