Credit: Petri Murto
A collaborative team of researchers from Northumbria, Cambridge, Imperial, and Loughborough universities has developed a simplified structure for blue OLEDs. The design could provide cheaper and more stable systems while improving color accuracy and stability.
OLEDs, or organic light-emitting diodes, are commonly found in modern smartphones and displays and are often more efficient than other technologies. Despite their vivid picture quality and efficiency, OLEDs are comparatively expensive and have shorter lifespans. Additionally, pixels emitting blue light are the least stable and are also susceptible to burn-in.
In the research, published in Nature Materials, the team of researchers outline a new design that overcomes these problems and could lead to less expensive systems with improved blue light stability. In typical OLEDs, an organic semiconductor is layered between two electrodes with the emissive layer lighting up when electrified. Ideally, most of the electrical energy introduced should be converted into light, however oftentimes the energy is diverted and degrades the structure as is the case with blue OLEDs.
To better understand the OLEDs, the team conducted a spectroscopic analysis of the molecules' triplet energies. This analysis provided the team with crucial information regarding how the energy transfer process works. Armed with this information, the team designed a novel light-emitting molecule, with shields added to block destructive energy pathways.
"With this new molecule we have created a channel to develop more efficient OLEDs that will drive down the energy consumption of our devices in the information era,” said Dr. Marc Etherington, Assistant Professor in Molecular Photophysics at Northumbria University. "As we all work towards net zero targets, this could have a significant impact for both manufacturers and consumers."
"OLED screens have great picture quality and carry a high premium. However, OLED TVs don't last as long as other screens," added Dr. Daniel Congrave, from the University of Cambridge. "Pixels that emit blue light are essential for a practical display but are also where the problems lie. We've designed a molecule that's allowed us to simplify the emissive layer of the blue pixel to only two components, while maintaining high efficiency, which could help to drive down cost."
The findings presented by the researchers will aid future developments while improving device performance.