Numerical simulation of transient and steady-state behavior of heterostructure organic LEDs

We present self-consistent numerical simulations of multilayer organic light-emitting diodes in both steady-state and pulsed operation that allow for a deeper understanding of charge accumulation, electric field and recombination zone confinement effects due to internal interfaces. Comparison to experimental transient data is given for bilayer LEDs based on Alq₃. The electric field predominantly drops across the Alq₃ layer with the electroluminescence delay time determined by electrons passing through this layer. The recombination zone width is limited by the exciton diffusion length, and the current balance highly sensitive to the cathode injection barrier