The use of a composite film that includes a high RI domain within the layers of an encapsulation stack can significantly enhance the light extraction efficiency and the integrated current efficiency of an OLED device that incorporates the film, relative to an OLED device that does not include such a film, but is otherwise the same. By way of illustration, various embodiments of the encapsulation stacks in accordance with the present teachings increase the extraction efficiency of an OLED device by at least 30% (e.g., by 30% to 40%) and the integrated current efficiency of an OLED device by at least 70% (e.g., by 70% to 100%). In addition, encapsulation stacks that include the composite films can reduce the viewing angle dependence of the emitted light, resulting in a higher quality display.

Examples of inorganic materials useful for fabricating inorganic barrier layers of a multilayered encapsulation stack can include, for example, various nitrides, oxides, and oxynitrides, such as one or more of silicon nitrides (SiN_x), silicon oxides, Al₂O₃, TiO₂, HfO₂, and silicon oxynitrides (SiO_xN_y). The inorganic barrier layers can be deposited or otherwise formed over active regions and may be blanket coated (e.g., via chemical and/or physical vapor deposition) over the entirety, or substantially the entirety of the exposed surface of a substrate and active regions.