Synthesis, characterization, and photo- and electro-luminescence of new Ir(III) complexes with carrier transporting group-functionalized dibenzoylmethane ligand for green phosphorescent OLEDs

Two new iridium(III) complexes containing the coumarin derivatives as cyclometalated ligands (L) and the carrier transporting group-functionalized dibenzoylmethane as ancillary ligands have been successfully synthesized and characterized. The X-ray crystal structure analyses of the free ligands and the complex containing a carbazole-functionalized dibenzoylmethane as ancillary ligand were described. The photophysical properties of the Ir(III) complexes were examined via ultraviolet-visible, photoluminescence spectroscopic spectra. The good thermal stability of the Ir(III) complexes was demonstrated by the thermogravimetric analysis. The doped light-emitting devices using the Ir(III) complexes as dopants were fabricated. The devices based on the complex containing a carbazole-functionalized dibenzoylmethane as ancillary ligand possess better performance as compared with the devices fabricated by the complex containing a 1,3,4-oxadiazole-functionalized dibenzoylmethane as ancillary ligand. The devices based on the former Ir(III) complex with a 15   wt% doping concentration exhibit a maximum efficiency of 13.8   cd/A and a maximum brightness of 4955.7   cd/m 2 .