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.