Two Novel Neutral Cyclometalated Iridium(III) Complexes Based on 10,11,12,13-Tetrahydrodibenzo[a,c]phenazine for Efficient Red Electroluminescence

Two novel neutral phosphorescent iridium(III) complexes (Ir1 and Ir2) were rationally designed and synthesized with high yields using 10,11,12,13-tetrahydrodibenzo[a,c]phenazine as the main ligand. The two complexes showed bright-red phosphorescence (625 nm for Ir1, and 620 nm for Ir2, in CH2Cl2), high-luminescence quantum efficiency (0.32 for Ir1, and 0.35 for Ir2), obvious solvatochromism and good thermostability. Then, they were used to fabricate high-efficiency red OLEDs via vacuum evaporation; the maximum current efficiency, power efficiency, and external quantum efficiency of the red devices based on Ir1 and Ir2 are 13.47/15.22 cd/A, 10.35/12.26 lm/W, and 10.08/7.48%, respectively.