| Summary: | 碩士 === 中原大學 === 化學工程研究所 === 93 === Recently, organic light emitting devices (OLED) have attracted much interest in industry. However, the lifetime of OLED shows relatively poor stability. One of the main issues is the formation of dark spots due to moisture and/or oxygen ingress. Thus, a barrier layer is needed in OLED encapsulation. Nowadays, the encapsulation of OLED is covered with glass or metal and therefore limited the application of flexible OLED.
In this study, we reported the water vapor transmission rate (WVTR) of silicon-based barrier film (including nitride and oxide), deposited by RF reactive magnetron sputtering without substrate heating, as a function of reactor pressure, gas flow ratio and coating thickness. It was found that while the WVTR of bare PET film was 38 g/m2/day when measured at 60 oC and 95 % RH, the WVTR of SiNx/PET and SiOx/PET composite films, deposited under the optimal conditions, were about 0.63 and 1.69 g/m2/day, respectively. It was also found that the critical coating thickness of SiNx and SiOx films were 30 nm and 20 nm, and the optical transmittance of nitride and oxide films were over 90 %. According to the series resistance model, the WVTR of PET was 17500 and 48000 times of the oxide and nitride barrier films. From the time lag method, the diffusivity of silicon-based barrier films was 1/106 of the original PET film. From these results, the silicon-based barrier films deposited in this work should be very suitable for encapsulating OLED.
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