Stable orange and white electrophosphorescence based on spirobifluorenyltrifluoromethylpyridine iridium complexes

• Ligand 2-(9,9′-spirobifluoren-2-yl)-5-trifluoromethylpyridine (sfp-5CF3-py).
• Complexes (sfp-5CF3-py)2Ir(acac) and (sfp-5CF3-py)2Ir(pic) were prepared.
• Orange devices emitted at 580 and 568 nm with efficiencies of 21.6 and 35 cd/A.
• Dual emitting devices included orange complexes and blue (FIrPic) phosphor layers.
• White-emissive device showed CIE coordinate of (0.33, 0.39) with efficiency of 13.8 cd/A.

Novel complexes bis[2-(9,9′-spirobifluoren-2-yl)-5-trifluoromethylpyridinto-C3, N] iridium (acetylacetonate) (8) and bis[2-(9,9′-spirobifluoren-2-yl)-5-trifluoromethyl-pyridinto-C3, N] iridium (2-picolinic acid) (9) were synthesized. Trifluoromethyl group and 2-picolinic acid were incorporated to tune luminescent color and spirobifluorene with supramolecular steric hindrance was introduced to suppress intermolecular interaction. The orange-emissive electrophosphorescent devices for 8 and 9 exhibited stable electroluminescent (EL) peaks at 580 (or 584) and 568 (or 572) nm at the different voltages, and maximum current efficiencies of 21.6 and 35 cd/A. The white-emissive devices of the dual emitting layer based on the orange (8 or 9) and blue (FIrPic) phosphor showed CIE coordinates of (0.32, 0.37) and (0.33, 0.39), and maximum current efficiencies of 10.6 and 13.8 cd/A. The CIE coordinates with the increasing of the operating voltage were stable. High efficiency and slow decay of devices indicated that 8 and 9 were highly efficient orange emitters.