Improved performance and stability of organic light-emitting devices with Al–Cu alloy cathode

Abstract

We have developed a stable green organic electroluminescent (EL) device by using an Al–Cu alloy as a cathode, which has better performance and reliability than the device with an Al cathode. The device with an Al–Cu alloy cathode achieved an EL efficiency of 3.78cd∕A(2.18lm∕W) at 20mA∕cm2 and the operating voltage was 5.46 V, while device with Al cathode had an EL efficiency of 3.1cd∕A(1.34lm∕W) and 7.3 V at the same drive condition. The Al–Cu device achieved a 20% decay lifetime (t80) of 1234 h at an initial brightness of 756cd∕m2, which is twice the lifetime of conventional device with the state-of-the-art LiF∕Al cathode.