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 IrCh center dot 3H(2)O at 80 degrees 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/m(2) at a current density of 115.6 mA/cm(2) and a maximum external quantum efficiency of 20.2% at 0.18 mA/cm(2). (C) 2009 Elsevier B.V. All rights reserved.