Lifetime study of single layer and stacked white organic light-emitting diodes

The lifetime of phosphorescent white organic light-emitting diodes (PHWOLEDs) was studied by changing the device structure of the PHWOLEDs. Four PHWOLEDs with different emitting layer structures were fabricated and the lifetime was investigated. Long lifetime was obtained in the device with orange/blue/orange stacked emitting structure, while the color change after lifetime test was minimized in the single emitting layer PHWOLED.