On the origin of the color shift in white-emitting OLEDs

White-emitting organic light-emitting modes (OLEDs) notoriously suffer from brightness-dependent color shifts. Based on experimental data and fundamental considerations about charge-transport and trapping, a quantitative model is developed which gives insight into the origin of this shift and describes the experimental data extremely well. Having understood the major contribution to the spectral instability, a device architecture is designed that shows excellent color stability over a wide range of brightness levels.