Organic light-emitting diodes (OLEDs) have emerged as a leading display technology owing to their low power consumption, ultra-thin form factor, flexibility, fast response time and excellent color-rendering properties. New phosphorescent materials have enabled OLEDs’ internal quantum efficiencies to reach nearly 100% and external quantum efficiencies for red, green and blue OLEDs to exceed 30%.
However, efficiencies typically decrease at higher brightness and current density due to reduced charge confinement and quenching through bimolecular and exciton-polaron mechanisms. While recombination dynamics of charge carriers in phosphorescent OLEDs can play a vital role in performance metrics and device optimization, these processes are largely a mystery.
A paper co-authored by experts at Dow Chemical Co. and Michigan State University details experimental work the team performed to determine a recombination profile that could help enable improved OLED performance. Available at ScienceDirect, the paper provides a wealth of information, detailing results that encourage further exploration of recombination profiles and other relevant aspects of OLEDs’ makeup that may help optimize OLED host configurations for high brightness and high performance.