Rapid progress in the performance of organic light-emitting devices (OLEDs) has positioned the technology as a potential replacement for current flat panel display applications since the advantages of the efficient emissive, fast response time, wide view angle and fabrication on a flexible substrate. However, the lifetime issue causes the limitation of mass production. One main factor is that the highly sensitivity to moisture and oxygen causes emission area decrease and dark spot. Effective encapsulation to prevent the ingression of water and oxygen to the devices layers is currently research interests to achieve adequate lifetimes.