Encapsulation of organic light-emitting devices for the application of display

Organic light-emitting diodes (OLED) is being considered as one of the most potential technology for the application of flat panel display (FPD) due to the low driving voltage, high luminance and high efficiency. Furthermore, OLED displays with plastic substrate also have many attractive features, such as ultra-thin and light in substrate. However, short operation-time hinders the process of OLED technology to industrialization due to its extremely sensitive to the operation environment. The key issues in achieving such displays are how to protect flexible OLED (FOLED) from moisture and oxygen. In this paper, some recent progresses in OLED packaging have been described and compared, such as the characteristics of oxygen and water permeability in different species of plastic substrates, the merits and demerits of chemical, physical and hybrid encapsulation methods. Finally, effects of the barrier film onto a plastic substrate and passivation film on the performance (efficiency and lifetime) OLED device have been discussed. In addition, in order to observe the roughness of passivated film, the oxygen and water permeability, and the fabrication method of FOLED , some widely-used measurement technology have also been reviewed.