High efficient two color white phosphorescent organic light emitting diode

We report on high efficient white organic light emitting diodes comprising the two phosphorescent emitter materials platinum(II)[2-(4',6'-difluorophenyl)pyridinato-N,C(2)')](2,4-pentanedionato) (FPt1) and iridium(III)bis[similar to 4,6-difluorophenyl-pyridinato N, C(2)']picolinate (FIrpic). Investigating the influence of the dopants in the emission layers on the device performance, a series of devices with different FIrpic and FPt1 concentrations have been processed. After optimizing the device with respect to efficiency and white color coordinates the influence of a thickness variation of the emission layers was investigated. The experiments revealed that the device performance is more sensitive to the parameters of the emission layer containing FPt1. Additional optical simulations showed that interference effects play a crucial role in this device setup. The optimized device resulted in an external quantum efficiency of 10%, a power efficiency of 16 lm/W, near warm white color coordinates of 0.39/.41, and a color rendering index of 81 at 1000 cd/m(2). (C) 2008 American Institute of Physics. [DOI: 10.1063/1.2975968]