On the exciton profile in OLEDs-seamless optical and electrical modeling

We present a comprehensive model to simulate organic light-emitting devices (OLEDs) that includes a seamless coupling of charges, excitons and photons. The comprehensive model accounts for the position dependent exciton lifetime due to the optical environment in the multilayer OLED structures. We first study the effect of different charge mobilities and quantum efficiencies of the light-emitting material on the exciton profiles. Moreover, we discuss the extension of an optical model to account for the exciton dynamics. This comprehensive optical model is validated and justified on the basis of consistency checks. Namely, we show that our comprehensive optical model can take the cavity effects as seen in simulation results of the comprehensive electrical model into account. The advantage of the comprehensive optical model is a quick and accurate insight into the exciton physics if applied together with a nonlinear least square (NLSQ) fitting method. Finally, we apply the comprehensive optical model with the NLSQ-method in order to extract the exciton profiles from emission spectra of a blue light-emitting polymer diode (PLED) measured at different current levels.

Presentation of a comprehensive electrical simulation which includes a seamless coupling of charges, excitons and photons. The model is applied to measured emission spectra of a PLED in order to extract the emission profile.Figure optionsDownload as PowerPoint slideHighlights
► Fully coupled electronic-excitonic-photonic device model.
► Allowing for accurate determination of the emission profiles in OLEDs both from electrical simulations and an analysis of measured emission spectra.
► Influence of the optical environment on the dipole decay rate is accounted for.
► Applied the method to polymer OLED data.