Ukrainian scientist helps develop stretchable OLED that can double in size without dimming
Researchers at Drexel University in the United States and Seoul National University have made major progress on a stretchable OLED display that can bend, twist and stretch while keeping a bright, stable glow and record efficiency.
Source: TechSpot, a popular technology news and reviews website
Details: The new displays are based on a class of materials known as MXenes: ultrathin, highly conductive sheets that combine the mechanical resilience of metals with the flexibility of polymers. Professor Yury Gogotsi, a Ukrainian scientist at Drexel University and a co-discoverer of MXenes, led the research group behind the development.
The researchers showed that MXenes used as transparent electrodes in OLED displays outperform the industry standard, indium tin oxide (ITO), in key areas, particularly stretchability and brightness. The displays can expand to twice their size without any loss of brightness.
OLED displays are usually built from a multilayer structure of conductive and organic layers that emit light when positive and negative charges meet. For decades, an ITO film served as a stable anode but it was too brittle and cracked under strain.
MXenes address ITO's weaknesses by forming thin, flexible films just 10 nanometres thick that maintain conductivity even when stretched. Displays using MXenes reached an external quantum efficiency of 17% against a theoretical maximum of 20%. This indicates how efficiently electrical energy is converted into visible light and is a record level so far for stretchable OLED displays.
The researchers also added two new organic layers to the OLED. One directs positive charges to the light-emitting region and the other recovers energy that would usually be lost as heat. Together, these layers help maintain high brightness and stability even under significant stretching or bending.
Such stretchable OLED displays could be used in many areas, including industrial settings, robotics, clothing and wearable devices. One application highlighted by Gogotsi would embed displays directly into clothing to monitor people's health.
However, the technology is not expected to be rolled out soon. Researchers still need to solve stability issues common to all stretchable OLED displays. Current materials cannot yet sustain light emission for long enough to meet customer requirements.
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