Interfaces in organic light emitting devices: Quenching of luminescence

The importance of the interracial properties in organic light emitting devices (OLED) is well recognized. We have studied the formation of interfaces that occurs in OLEDs using mainly surface/interface analytical techniques in a well controlled ultra high vacuum (UHV) environment. The results have shown that microscopic surface and interface properties are intimately related to the device characteristics and performance. Specifically, the metal electrode material is observed to quench strongly the luminescence of the organic material in the interface region. Proper treatments of the interface may at least partially recover the quenched luminescence. The implications of these results in the design and operation of organic light-emitting devices are discussed.