A New Bis-Cyclometalated Iridium (III) Complex as a Triplet Emitter in Organic Light Emitting Devices

Abstract

We report a new Iridium(III) complex and the study of its optical, electrochemical and electroluminescence properties. The crystal structure shows an octahedral environment around Ir(III) center. Density functional theory (DFT) calculations indicate the contribution of the d-orbitals of Ir and the π-orbitals of the cyclometalating and ancillary ligands toward HOMO, whereas LUMO is concentrated on only the cyclometalating ligand. These complexes emit in the sky blue color region from an admixture of triplet metal-to-ligand-charge-transfer (³MLCT) and ligand π-π* states. A maximum external (ηex) quantumefficiency and luminance efficiency of 2.4% and 5.5 cd/A at 0.12 mA/cm2 was obtained from the device consisting of a 5% doped polymeric and low molecular host. A maximum brightness of 10,200 cd/m² at 14.8 V was obtained from the device.