High-contrast and high-efficiency microcavity top-emitting white organic light-emitting devices

Microcavity top-emitting white organic light-emitting devices (TEWOLEDs) with M/(Alq3/Ag)2 anode (M = Ag, Au or Al, Alq3 is tris (8-hydroxyquinoline) aluminum) were investigated. All devices show white emission and the optical properties of the anode play an important effect on the efficiency and contrast of the devices. The maximum efficiencies of the top-emitting devices are comparable to the corresponding bottom one and the contrasts of top-emitting devices are much higher than that of the bottom one. The results indicated that such TEWOLEDs are compatible with complementary metal oxide semiconductor or organic thin film transistor techniques which using Au or Al as electrode.