Thin-film encapsulation of organic light-emitting devices

Organic light-emitting devices (OLED) are extremely sensitive to moisture and oxygen. Without high-performance hermetic seals, the life of these devices is limited. Bottom-emitter OLEDs are commonly sealed using epoxy and cover glass with large amounts of desiccant. In top-emitter OLEDs the light passes through the cover glass on which the desiccant typically resides. Thus, transparent thin-film encapsulation without any desiccant is most desirable. This paper reports the results of a robust thin-film encapsulation method that utilizes a layer of aluminum oxide deposited by atomic layer deposition (ALD) process as the primary moisture barrier. More than 1000 h in 85 degrees C and 85% RH testing has been observed without significant device degradation caused by moisture. Data corroborating this method's superiority over other physical deposition methods for OLED encapsulation are also presented. (c) 2005 American Institute of Physics.