High efficient polymer light-emitting diode based on a new iridium(III) complex with pyrazolone ligand

A new iridium complex containing two 2-(thiophen-2-yl)quinoline ligands and one single monoanionic ligand 1,3-diphenyl-4-phenylacetyl-5-pyrazolone was designed and synthesized. Its photophysical, electrochemical and electrophosphorescence properties were investigated. The iridium complex in solution showed characteristic phosphorescence with a high quantum efficiency of 19% and lifetime of 0.67 μs. Importantly, a saturated red polymer-based electrophosphorescent device with high external quantum efficiency of 8.5% and CIE coordinate of (0.64, 0.33) was fabricated by using this complex as dopant.