The present invention relates to organic light emitting devices (OLEDs). The
devices of the present invention are efficient white or multicolored phosphorescent
OLEDs which have a high color stability over a wide range of luminances. The devices
of the present invention comprise an emissive region having at least two emissive
layers, with each emissive layer comprising a different host and emissive dopant,
wherein at least one of the emissive dopants emits by phosphorescence.
