Tandem white phosphorescent organic light-emitting diodes based on interface-modified C60/pentacene organic heterojunction as charge generation layer

The significant improvement of power efficiency and efficiency roll-off in tandem white organic light-emitting diodes (WOLEDs) was achieved using interface-modified C-60/pentacene organic heterojunction as charge generation layer (CGL). The resulting tandem WOLED exhibits a maximum power efficiency of 53.8 lm W-1 and a maximum current efficiency of 101.5 cd A(-1) without any out-coupling techniques. More importantly, the efficiency roll-off is greatly improved, yet remaining power efficiency of 53 lm W-1 at 100 cd m(-2) and 45 lm W-1 at 1000 cd m(-2), which outperforms that of the conventional CGL-based tandem WOLED. This clearly demonstrates that the organic heterojunction is a promising CGL for high-performance tandem WOLEDs. (C) 2011 American Institute of Physics. [doi:10.1063/1.3628317]