Solution Processed Green Phosphorescent Organic Light-Emitting Diodes Based on Phenylpyridine Derivatives Using Small Molecule Host

A novel cyclometalated ligand 2-(2,4-dimethoxyphenyl)-5-trifluoromethylpyridine (MeO(2)CF(3)ppy), and its complexes bis[2-(2,4-dimethoxy-phenyl)-5-trifluoromethyl pyridinato-N, C-2']iridium acetylacetonate (MeO(2)CF(3)ppy)(2)Ir(acac) and bis[2-(2,4-Dimethoxy-phenyl)-5-trifluoromethyl pyridinato-N, C-2']iridium pyrazolate (MeO(2)CF(3)ppy)(2)Ir(prz) were synthesized, respectively. Trifluoromethyl (CF3) and dimethoxy group (MeO2) were introduced into main ligand for color tuning. The green emitting PhOLEDs, based on ITO/PEDOT:PSS (40 nm)/TCTA:TPBi: Ir(III) complex (80 nm)/Bphen (20 nm)/LiF (0.7 nm)/Al (120 nm) were fabricated. The solution-processed PhOLEDs based on (MeO(2)CF(3)ppy)(2)Ir(acac) exhibited a maximum quantum efficiency of 3.40% and luminance efficiency 8.32 cd/A with CIE coordinate of (0.33, 0.63).