Calculation of lateral optical energy flow in bound modes in organic light-emitting diodes

Abstract

We investigate the lateral energy flow of light bound to an OLED (i.e., light that cannot be coupled to the substrate or air mode), with a focus on the attenuation characteristics. A methodology is developed for approximating the total bound field as a superposition of the individual guided modes constructed from multilayer eigenmodes with complex wave vectors. The field distribution and surface energy flow density obtained from our approximate expressions are found to be well matched to those calculated using the Green’s function formalism. The method presented in this study provides mode-based interpretation of the surface energy flow density versus distance characteristics, and can be used in designing OLEDs for applications where the optical energy transported by the bound field is of interest. • The complex photonic band structure of an OLED is calculated. • The bound-mode field of an OLED is constructed from eigenmodes with complex wave vectors. • The attenuation characteristics of the surface energy flow density are quantitatively described.