Researchers have developed a new OLED display that can be stretched to more than double its length while maintaining light emission and sharp images. This development opens the door to a wide range of wearable electronics.
Organic light-emitting diodes (OLEDs) contain thin, flexible sheets of small organic molecules that emit light in response to an electric current. OLEDs are more energy efficient than the older LED and LCD displays and are used to make TV and computer screens, as well as displays for smartphones and handheld game consoles.
After decades of development, OLED has become one of the most advanced electroluminescent technologies. But researchers are always looking for new uses. Low voltage, high efficiency, high brightness and low cost make his OLEDs an ideal technology for integration into wearable and implantable devices. However, it needs tweaking to improve its softness and stretchability.
Enter a researcher at the University of Chicago. They tackled the tight chemical bonding and stiffness of his current OLEDs and developed an entirely new, more stretchy alternative.
“The materials currently used in these state-of-the-art OLED displays are very brittle. “Our goal was to create something that uses stretchable polymers while still retaining the electroluminescence of OLEDs.”
Researchers with molecular engineering backgrounds knew that developing stretchable OLEDs would require molecular manipulation. After using computational prediction to develop new OLED polymers and testing several prototypes, researchers found a winner in thermally activated delayed fluorescence (TADF). This is a highly efficient way of enabling organic materials to convert electricity into light.
Softness and flexibility were improved by embedding alkyl, an organic chemical containing only carbon and hydrogen atoms arranged in chains, into the polymer between the TADF units. The newly designed OLED could be stretched to more than double its original length without compromising its luminous ability or display of sharp images.
“We were able to develop atomic models for new polymers of interest. We used these models to simulate what would happen to these molecules if we tried to pull them and bend them. Research: “Now that we understand these properties at the molecular level, we have a framework for designing new materials with optimized flexibility and luminescence.”
This new breed of OLED looks better than Samsung’s wearable health monitoring system announced in 2021. This system can stretch up to 30% without negatively impacting display or monitoring performance. The researchers say their stretchable OLED devices could have broad applications in next-generation wearable electronics and health sensors.
“This is the class of material we need to finally be able to develop truly flexible screens,” said de Pablo. “This work is really foundational and I hope it will enable a lot of technology that we haven’t even thought of yet.”
The team plans to develop a new version of the display, integrating additional colors into the fluorescence and improving performance and efficiency.
“The goal is to eventually reach the same level of performance as existing commercial technologies,” said Wang.
This research Natural materials.
Source: University of Chicago
