An organic light-emitting diode (OLED) device, comprising: a substrate; an OLED comprising first and second electrodes and one or more layers of organic light-emitting material formed between the electrodes, wherein at least one electrode comprises a transparent electrode, the transparent electrode and layer(s) of organic light-emitting material having a first refractive index range; and an encapsulating cover; wherein at least one of the substrate or cover comprises a transparent substrate or cover having a second refractive index and through which light from the OLED is emitted; and further comprising a light scattering layer located between the substrate and cover, and a transparent low-index element having a third refractive index lower than each of the first refractive index range and second refractive index and located between the scattering layer and the transparent substrate or cover.