Highly efficient orange organic light-emitting diodes using a novel iridium complex with imide group-containing ligands

Abstract

We report the synthesis and device characterization of a novel iridium complex using a phenylpyridine derivative containing an imide functional group as a bis-cyclometallized ligand ((impy)(2)Ir(acac)) for orange organic light-emitting diodes (OLEDs). The photoluminescence of the dopant emits orange light with the main peak of 560 nm and a shoulder of 595 nm. The OLEDs made with the synthesized dopant also produce intense orange electroluminescence at 568-572 nm wavelengths depending on the device geometry. Very high peak external quantum efficiencies of 13.8-14.4%, peak power efficiencies of 29.2-32.7 lm/W, and low operation voltages of 5.3-5.4 V at 1000 cd/m(2) have been demonstrated for the orange OLEDs.