Electroluminescence of a novel europium complex

Abstract

Electroluminescent devices using a ternary europium complex Eu(DBM) 3(hhpy) 2 (dibenzoylmethane, DBM; hexahydro pyridine, hhpy) as an emitting layer, poly(vinyl-carbazole) (PVK) as a hole-transporting material and tris-(8-hydroxyquinoline) aluminum (Alq 3) as an electron-transporting material have been fabricated. When only using Eu(DBM) 3(hhpy) 2 as the emitting layer, luminance of 2.52 cd/m 2 with pure Eu 3+ EL emissions from devices is achieved. Introducing a hole transporting material PVK and an electron transporting material 2-(4-biphenylyl)-5-(4- tert-butylphenyl)-1,3,4-oxidiazole (PBD) in the emitting layer, luminance of 100 cd/m 2 is achieved, and the eletroluminescence efficiency is enhanced by about two orders of magnitude.