Highly efficient top-emitting white organic electroluminescent devices

Abstract

We have developed highly efficient white top-emitting organic light-emitting devices with broad emission by modifying both the anode and cathode. To alleviate the undesirable microcavity effect and obtain “broad” white emission, a CFx-coated Ag anode and an index-matching layer (SnO2) capped on a thin Ca∕Ag cathode with a maximum transparency of 80% were employed. A top-emitting broad white-light device, based on the dual-layer architecture of light blue and yellow emitters with one of the highest EL efficiencies of 22.2cd∕A (9.6lm∕W) at 20mA∕cm2 and 7.3V with Commission Internationale d’Eclairage coordinates of (x=0.31,y=0.47), has been demonstrated.