Highly Efficient Polymer Light-Emitting Devices Using a New Phosphorescent Material

Abstract

A new phosphorescent material bis(2-phenyl-benzoimiazole) acetylacetonato iridium ((PBI)2IrAcac) is designed and synthesized. The absorption, photoluminescence and electroluminescence are measured. The polymer-based light-emitting devices which use polyvinylcarbazole (PVK) as host and (PBI)2IrAcac as emitter were fabricated. These light-emitting devices show a bright green emission at 548 nm. The device ITO/(PBI)2IrAcac:PVK/BCP/ Alq3/Mg:Ag shows a very high efficiency. A peak external quantum efficiency of 21.5 cd/A (5.8%) was obtained at 0.1 mA/cm2. The maximum brightness is 3840 cd/m2.