Flexible alumina films prepared using high-bias pulse power for OLED thin film encapsulation

To overcome the moisture sensitivity of flexible organic light-emitting diode devices (OLEDs), physical vapor deposition (PVD) technology can be used to prepare films with excellent density for thin film encapsulation (TFE). The internal stress in the film should be modulated to enhance the flexibility, which can prevent structural degradation. To address these issues, a filtered cathode vacuum arc (FCVA) equipped with a superlow duty ratio high-bias pulsed was used to prepare Al₂O₃ films with low internal stress (−57.6 MPa), excellent visible light transmittance, high packaging density, and good bending resistance. After 1000 bending cycles, the water vapor transmission rate (WVTR) for a film is increased to 5.57 × 10⁻³ g/m²/day at 85 °C and 85% relative humidity (R.H.). In addition, the molecular dynamics (MD) is employed to investigate the mechanism of film internal stress release, as well as the shallow implantation of ions brought about by high-bias pulse.