The Pritzker School of Molecular Engineering (PME) at the University of Chicago has developed a stretchable light-emitting material that will enable the creation of truly flexible display screens. The new material can stretch more than twice its original length without disrupting its ability to emit light, while continuing to display a clear image. This light-emitting material has a wide range of applications, including wearable electronics, health sensors, and foldable computer screens.
Currently, most displays use OLED (organic light-emitting diode) technology, which is composed of small organic molecules sandwiched between conductors. However, the molecular building blocks of OLEDs have tight chemical bonds and stiff structures.
“The materials currently used in these state-of-the-art OLED displays are very brittle; they don’t have any stretchability,” said Professor Sihong Wang, who led the research with Professor Juan de Pablo. “Our goal was to create something that maintained the electroluminescence of OLED but with stretchable polymers.”
The new material required long polymers with bendable molecular chains to allow them to be stretchable, along with molecular structures in order to emit light very efficiently.
“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,” stated de Pablo. “Now that we understand these properties at a molecular level, we have a framework to engineer new materials where flexibility and luminescence are optimized.”
They were then able to create a design based on the use of “thermally activated delayed fluorescence,” which lets the materials convert electrical energy into light in a highly efficient way. This third-generation mechanism for organic emitters can provide materials with performance on par with commercial OLED technologies.
Future plans include the development of new iterations of the display, the integration of additional colors into the fluorescence, and improving the efficiency and performance.
“The goal is to eventually get to the same level of performance that existing commercial technologies have,” said Wang.