54.2: Tandem White OLEDs Combining Fluorescent and Phosphorescent Emission

Abstract Tandem white OLEDs with fluorescent and phosphorescent emission have been fabricated. Their electroluminescence performance is dependent on fluorescent blue‐emitting portion in a white spectrum. When CIEx = 0.33, CIEy = 0.35, the devices can achieve 22% external quantum efficiency, 50 cd/A, 25 lm/W, and ∼10,000 h lifetime, tested at 6.2 V and 1000 nits. If the blue‐emitting portion is reduced to produce color with CIEx = 0.34, CIEy = 0.40, the devices can exhibit ∼23% external quantum efficiency, 57 cd/A, 30 lm/W, and ∼30,000 h lifetime when tested at 5.9 V and 1000 nits.