Luminescent iridium(III) complexes with mixed 2-phenylpyridinato-C2, N and dithionate ligands for dopant emitter in OLEDs

Two new iridium(III) complexes with two cyclometalated ligands (2-phenylpyridinato-C2,N) and one monoanionic dithiolate (N,N′-dialkyl-dithiocarbamate or O,O′-dialkyl-dithiophosphate) as ancillary ligands have been synthesized, and characterized by 1H-NMR, IR, MS and EA. They are all emissive in both solid state and in solution at room temperature. The replacement of β-diketonate ligand (acac) by dithiolate ligand results in blue shift of emission wavelength in solution photoluminescence spectra. The OLED using complex (ppy)2Ir (Et2dtc) as dopant in emitting layer gives a maximum current efficieny of 2.9 cd/A and a maximum brightness of 2525 cd/m2 at 13 V.