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–Alq 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 Al 2O 3 (150 nm) and Al 2O 3(75 nm)/ZrO 2(75 nm). And the results indicated that the CIE coordinates is almost the same between with and without encapsulating. ► White top-emitting organic light-emitting devices (TEOLEDs) were fabricated with metal/organic multilayers cathode. ► The maximum current efficiency of the device can reach 9.51 cd/A. ► The cathode could adjust the optical characteristic of the devices to achieve white emission. ► The cathode could be also work as buffer layer to protect the devices when encapsulating.