Efficient white organic light-emitting devices based on phosphorescent iridium complexes

Mixing yellow and blue emissions is a commonly used approach for achieving white emission in organic light-emitting devices (OLEDs). However, as there are relatively few efficient yellow phosphors, their performance is often the bottleneck for the efficiency of phosphorescent white OLEDs (WOLEDs) based on “yellow plus blue” approach. Here, a yellow phosphorescent iridium complex, bis[2-(2-naphthyl)pyridine] (acetylacetonate) iridium(III), has been designed, synthesized and applied in WOLEDs by combining blue emission from iridium-bis-(4,6,-difluorophenyl-pyridinato-N,C2)-picolinate. Without using optical out-coupling or p–i–n confinement structure, the optimized WOLEDs demonstrate a maximum forward viewing power efficiency of 29.2 lm/W (37.2 cd/A and 12.6%) with CIE coordinates of (0.32, 0.45).