Synthesis and characterization of red phosphorescent iridium(?) complexes based on electron-acceptor modulation of main ligand for high efficiency organic light-emitting diodes

A new series of red phosphorescent iridium(?) complexes, (PT-TFP)2Ir(tmd), (PT-P)2Ir(tmd), and (PT-MP)2Ir(tmd) were synthesized for highly efficient red emitter of the organic light-emitting diodes (OLEDs). The main ligands consisted of electron-donor (phenanthren) and electron-acceptor (trifluoromethyl pyridine, pyridine, and methyl pyridine) were synthesized by Suzuki coupling reaction. The iridium(?) complexes based on main ligands and 2,2,6,6-tetramethyl-3,5-heptanedione(tmd) ancillary ligand were synthesized by Nonoyama reaction. Their luminescence properties were investigated by UV-visible spectroscopy and photoluminescence (PL) spectroscopy. The OLEDs devices were manufactured by vacuum deposition and These OLEDs devices were characterized by investigation of current density-voltage-luminance (J-V-L), current efficiency, power efficiency, external quantum efficiency (EQE), EL spectrum. The Ir(?) complexes will be used as a solution process dopant for the hybrid OLED devices.