Various aspects of a light extraction substrate, an organic light emitting device, and methods of fabrication are provided. A light extraction substrate of an organic light-emitting device includes a light-scattering layer disposed on a base substrate and contains a first material, and a number of holes (hole diameters ranging from 350 nm to 450 nm) extending between the first surface and the second surface. A planarization layer (thickness not greater than 200 nm) is disposed on the light-scattering layer and contains a second material.