Bright red light-emitting organic electroluminescent devices having a europium complex as an emitter

Organic electroluminescent (EL) devices with a trivalent europium (Eu) complex as an emitter were fabricated. Triple-layer-type cells with a structure of glass substrate/indium-tin oxide/ triphenyldiamine derivative (TPD)/Eu complex: 1,3,4-oxadiazole derivative (PBD)/aluminum complex (Alq)/Mg:Ag exhibit bright red luminescence upon applying dc voltage. The EL spectrum consists of extremely sharp emission bands, which is a typical luminescence spectrum of the Eu complex. Luminance of 460 cd/m2 with an emission peak at 614 nm is achieved at a drive voltage of 16 V. This is the highest luminance so far obtained for the EL cells having a Eu complex as an emitter.