Imagine a thin digital display screen so flexible that you can wrap it around your wrist and fold it in any direction, or bend it on the steering wheel of your car. Researchers at the University of Chicago's Pritzker School of Molecular Engineering (PME) have designed a material that can be bent in half or stretched to more than twice its original length, while also emitting fluorescent patterns.
The material described in the scientific journal Nature Materials has a wide range of applications, from wearable electronic devices and health sensors to foldable computer screens.
Sihong Wang, an assistant professor of molecular engineering, said, "One of the most important components of almost every consumer electronics we use today is the display screen. We have combined knowledge from many different fields to create a new display technology." He and molecular engineering professor Juan de Pablo led the research.
De Pablo added, "This is the type of material you need to ultimately develop a truly flexible screen. This work is indeed fundamental, and I hope it can achieve many technologies that we haven't even thought of
Most high-end smartphones and an increasing number of television displays use OLED (Organic Light Emitting Diode) technology, which sandwiches small organic molecules between conductors. When the current is turned on, small molecules emit bright light. This technology is more energy-efficient than old-fashioned LED and LCD displays and has been praised for its clear images. However, the molecular components of OLED have tight chemical bond and hard structures.
Wang said, "The materials currently used for these state-of-the-art OLED displays are very brittle; they do not have any stretchability. Our goal is to create a polymer that can maintain OLED electroluminescence but has stretchability
Wang and de Pablo now know what is needed to inject extensibility into materials - long polymers with flexible molecular chains, and what molecular structure is needed for organic materials to emit light very effectively. They set out to create new polymers that combine these two characteristics.
We have been able to develop atomic models of new polymers of interest, and through these models, we have simulated what happens when you pull these molecules and try to bend them. Now that we understand these characteristics at the molecular level, we have a framework to design new materials, where flexibility and luminescence ability are optimized
Having mastered the calculation and prediction of new flexible electroluminescent polymers, they manufactured several prototypes. As predicted by the model, these materials are flexible, stretchable, bright, durable, and energy-efficient.
A key feature of their design is the use of "thermally activated delayed fluorescence", which allows the material to efficiently convert electrical energy into light. The mechanism of this third-generation organic emitter can provide materials with the same performance as commercial OLED technology.
Researchers have previously developed stretchable neural morphology computing chips that can collect and analyze health on a flexible bandage