Birefringence and light emission from the polymer LED

Many thin film emissive devices use polymeric materials to produce the optical output. The long chain molecular structure of typical polymer materials, and the way in which thin layers of the material are produced in light-emitting devices, often results in a significant difference in the optical parameters in directions perpendicular and parallel to the layer. We use a classical model to investigate spontaneous emission from such anisotropic materials in planar multi-layer structures. By comparing the results of this model with those for which the emissive material is assumed to be isotropic, we highlight those performance aspects for which the anisotropy is important.