Magnetic field instead of endurance test: KAIST predicts blue OLED lifetime faster

Researchers at the Korea Advanced Institute of Science and Technology (KAIST) have presented a method for estimating the lifetime of blue phosphorescent OLEDs early on. Until now, devices have had to run for tens to hundreds of hours while their loss of brightness is measured. The study, led by Professor Seunghyup Yoo, was published in Nature Communications on September 30, with Kyung Hee University, Hanbat National University and the company ASTA also involved.

The team ran the OLEDs at constant current and varied the field strength with an electromagnet, making the devices glow slightly brighter. The researchers condensed the lifetime-related part of this response into a single metric. Among four device types with the same emitter but different structures, those with a smaller initial magnetic-field response kept their brightness longer.

Simulations suggest that during long-term operation, molecular bonds break and create defects that show up in the magnetic-field response. According to Yoo, the method could help select long-lived materials and device structures early in development. The team stresses, however, that further validation is needed and each device type must be analysed separately.