High efficiency top-emitting white organic light-emitting devices with a (metal/organic)2 cathode

White top-emitting organic light-emitting devices (TEOLEDs) were fabricated on a glass substrate with metal/organic multilayer of (Ag/Alq(3))(2) (Alq(3) is tris-(8-hydroxyquinoline) aluminum) as cathode. White TEOLEDs with high efficiency were obtained due to the microcavity effects. And the (Ag/Alq(3))(2) cathode, which adjusted the optical characteristics of the devices, played an important role. In addition, Alq(3)-Ag-lq(3) multilayer could work as a buffer layer, which would simplify the process of encapsulation for devices. We also calculated the electroluminescence spectrum of devices encapsulated with Al2O3 (150 nm) and Al2O3(75 nm)/ZrO2(75 nm). And the results indicated that the CIE coordinates is almost the same between with and without encapsulating. (C) 2011 Elsevier B.V. All rights reserved.