Hybrid warm-white organic light-emitting device based on tandem structure

We realized an efficient hybrid tandem warm white organic light-emitting device with extremely stable color purity in forward direction by employing an easy-fabrication charge generation unit (CGU) combining 1, 4, 5, 8, 9, 11-Hexaazatriphenylene-hexacarbonitrile with ultrathin bilayers of LiF and Al. The tandem white device exhibits maximum efficiencies of 37.3 cd/A, 23.3 lm/W and still remains at high efficiencies of 34.4 cd/A, 17 lm/W at the luminance of 1000 cd/m . When the operating current density increases from 5 mA/cm to 30 mA/cm , the variations in Commission Internationale de l'Eclairage (CIE) coordinates are only (0.007, 0.003). Moreover, we also studied the cause of color variation in tandem white device by performing systematic optical simulation and discovered the origin of alleviation in efficiency roll-off for tandem white device by applying triplet-polaron quenching (TPQ) model.