Preparation of SiO2 Passivation Thin Film for Improved the Organic Light-Emitting Device Life Time

To improve the organic light-emitting diode (OLED) lifetime, we prepared a SiO 2 thin film for OLED passivation using a facing target sputtering (FTS) system as a function of oxygen gas flow rate and working pressure. The properties of the SiO 2 thin film were examined by Fourier transform infrared (FT-IR), photoluminescence (PL) intensity measurement, field emission scanning electron microscopy (FE-SEM), and ultraviolet--visible (UV--vis) spectrometry that As a result, we found that a SiO 2 thin film is formed at a 2 sccm oxygen gas flow rate and results the minimum damage to the organic layer is observed at a 1 mTorr working pressure. Also, from the water vapor transmission rate (WVTR), we observed that all of the as-deposited SiO 2 thin films showed the ability of blocking moisture. After the properties were evaluated, an optimized SiO 2 thin film was applied to OLED passivation. As a result, the property of the OLED fabricated by SiO 2 passivation is similar to the OLED fabricated by glass passivation. However, the performance of OLED was degraded by enhancing of SiO 2 passivation. This is the organic layer of the device is exposed to plasma for a prolonged period. Therefore, a method of minimizing damage to the organic layer and optimum conditions for what are important.