Integrated optical model for organic light-emitting devices

One of the most important parameters of organic light-emitting devices (OLEDs) in their application for illumination or displays is their efficiency. In order to maximize the efficiency, one needs to understand all loss mechanisms and effects present in these devices and properly model them. For that purpose, we introduce an integrated model for light emission from OLEDs. The model takes into account the exciton decay time change and light outcoupling. Furthermore, it shows how to calculate the external quantum efficiency, the spectral radiance and the luminous current efficacy of OLEDs. The overall theory is experimentally verified through a range of measurements done on a set of green OLED samples with an Ir-based phosphorescent emitter. From the analysis of simulations and experiments one can estimate the charge balance in the OLED stack and the radiative efficiency of the emitter.