Importance of scattering and absorption for the outcoupling efficiency in organic light-emitting devices.

The outcoupling of light in organic light-emitting devices is one of the limiting parameters for obtaining a high external efficiency. A simple geometrical model is presented that allows one to estimate the importance of optical parameters such as mirror reflectivity, scattering probability, and device structure. The model allows the derivation of analytical expressions for the outcoupling efficiency in some simplified cases.