ACS Applied Materials & Interfaces 2011-08-01

Pure white organic light-emitting diode with lifetime approaching the longevity of yellow emitter.

Jwo-Huei Jou, Shih-Ming Shen, Yung-Cheng Tsai

Index: ACS Appl. Mater. Interfaces 8th ed., 3 , 3134-3139, (2011)

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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.