Fourfold power efficiency improvement in organic light-emitting devices using an embedded nanocomposite scattering layer

► The out-coupling efficiency of OLEDs can be improved by the nanocomposite film. ► We used the large-sized TiO2 nanoparticles to induce scattering. ► The large-sized TiO2 can diminish the light reflection back to the ITO layer. ► We used the small-sized TiO2 nanoparticles to improve the refractive index. ► The small-sized TiO2 can flatten the surface of the nanocomposite film.