Abstract
A high-efficiency pure white organic light-emitting diode was fabricated with lifetime approaching that of the low-excitation-energy (yellow) emitter containing counterpart, or six times that of the deep-blue counterpart. The white device was composed of two emission layers with mixed hosts of different compositions. They were respectively doped with yellow rubrene and deep-blue 4,4′-bis-[4-{N,N,N′,N′- tetrakis-(4-fluoro-diphenylamino)- phenyl}-vinyl]-biphenyl. The resulting efficiency was 6.0 lm/W (12.4 cd/A) at 20 mA/cm 2 . The long device lifetime may be attributed to the double mixed-host architecture employed that effectively dispersed the injected carriers into three different recombination zones and consequently diluted the damaging effect arising from the accumulated charge from un-recombined carriers, hence leading to a markedly improved lifespan. © 2011 American Chemical Society.