In this paper, a thin film passivation for a gas barrier is performed using Al2O3. The passivation film shows a thickness of 50 nm. We deposit an Al2O3 layer using ALD. This material is used to protect devices from external oxygen as a barrier thin film. After this material is deposited, we measure IVL and its lifetime. The lifetime is increased to 15 times compared to that of OLED, which is non-passivated. We expect that as using this material the lifetime and luminance of OLED are to be increased. We hope that this article should be the basis for developing OLED.