High-performance full phosphorescent warm white organic light-emitting diodes with external quantum efficiency of 34.5%

In this work, we have reported full phosphorescent warm white organic light-emitting diodes (WOLEDs) consisting of three light-emitting layers not only achieving high external quantum efficiency (EQE) but also demonstrating significant color stability and low efficiency roll-off. The WOLED exhibits slight shift in Commission Internationale de l’Eclairage coordinates (CIEx,y) from (0.409, 0.405) at 1000 cd m−2 to (0.372, 0.398) at 10000 cd m−2. Moreover, the maximum external quantum efficiency is as high as 34.5% and remains >28% over wide brightness range of 100 cd m−2 to 5000 cd m−2. Our work not only provides effective design strategy for physiologically friendly warm WOLEDs but also paves the way for achieving high EQE and low roll-off all phosphorescent WOLEDs.