Researchers at the Organic Semi­conductor Centre in the School of Physics and Astronomy, and the School of Chemistry at the University of St Andrews have developed a new approach to designing efficient light-emitting materials. Light-emitting materials are used in organic light-emitting diodes (OLEDs) that are now found in the majority of mobile phone displays and smart­watches, and some tele­visions and automotive lighting.

The latest generation of emitter materials under development produce OLEDs that have high efficiency at low brightness, but suffer reduced effi­ciency as the brightness is increased to the levels required for lighting and outdoor applications. This problem is known as “efficiency roll-off”. Now, the researchers have identified the combination of features of materials required to overcome this problem. Guidelines developed by the team of researchers, led by Ifor Samuel and Eli Zysman-Colman, will help OLED researchers develop materials that maintain high effi­ciency at high bright­ness, enabling the latest materials to be used for appli­cations in displays, lighting and medicine.

Commenting on the research, Zysman-Colman explained that the findings “provide clearer insight into the link between the properties of the emitter material and the per­formance of the OLED.” Ifor Samuel said, “Our new approach to this problem will help to develop bright, efficient and color­ful OLEDs that use less power.” (Source: U. St Andrews)

Reference: S. Diesing et al.: A figure of merit for efficiency roll-off in TADF-based organic LEDs, Nature 627, 747 (2024); DOI: 10.1038/s41586-024-07149-x

Link: Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, UK