A highly efficient tris-cyclometalated iridium complex based on phenylphthalazine derivative for organic light-emitting diodes

A novel ligand 9-(4-(4-chlorophenyl)phthalazin-1-yl)-9H-carbazole (HCPC) was designed and prepared, and the corresponding tris-cyclometalated iridium(III) complex Ir(CPC)3 was readily synthesized by the reaction of the ligand with IrCl3 · 3H2O at 80 °C for 20 h. A highly efficient organic light-emitting device using this complex as a dopant was obtained. The device fabricated by solution process showed a maximum luminance of 2948 cd/m2 at a current density of 115.6 mA/cm2 and a maximum external quantum efficiency of 20.2% at 0.18 mA/cm2.