Color Tuning Dopants for Electrophosphorescent Devices: Efficient Blue Phosphorescence Pyrrazole and Carbene Complexes

In this paper, we describe several new Ir complexes for achieving efficient blue electrophosphorescence. The approach described here for achieving blue phosphorescence is to shift the cyclometallated ligand from phenyl-pyridine to either a phenyl pyrrazole or phenyl-imidazole. Both complexes emit strongly in the near UV, however, only the imidazole complex (carbene ligand) emits strongly at room temperature.