Enhanced outcoupling from organic light-emitting diodes using aperiodic dielectric mirrors

Aperiodic dielectric stacks between the substrate and transparent anode in organic light-emitting diodes are used to improve the optical outcoupling efficiency. The authors demonstrate that a nine-layer SiO2/SiNx aperiodic dielectric stack improves the brightness by 80% within a 60 degrees viewing cone for a red-emitting organic light-emitting diode, while maintaining a Lambertian emission pattern. As the refractive index contrast between the two materials used in a two-component multilayer dielectric stack is increased, a brightness improvement of 170% in a 60 degrees viewing cone is achievable while maintaining a Lambertian emission profile. (c) 2007 American Institute of Physics.