Highly efficient single-layer phosphorescent white organic light-emitting diodes using a spirofluorene-based host material

Highly efficient phosphorescent white organic light-emitting diodes (PHWOLEDs) were developed by the doping of phosphorescent blue and red dopants in a spirofluorene-based phosphine oxide host material. A high quantum efficiency of 18.3% and a current efficiency of 34.2 cd/A at 100 cd/m ² were obtained from the PHWOLED with the spirofiuorene-based phosphine oxide host material. In addition, a high power efficiency of 28.3 Im/W was achieved in the PHWOLED. The wide triplet bandgap of host and charge balance in the light-emititng layer were responsible for the high efficiency.