Modeling the width of exciton formation zone in organic light emitting diode

The width of exciton formation zone has been simulated in a single-layer organic light emitting diode (OLED) based on the model of carrier device lifetimes. The width of exciton formation zone decreases with device current density increasing. Increasing the thickness of emissive layer (EML) is able to widen exciton formation zone. There is an optimal value of EML’s charge carrier mobility to maximize the width of exciton formation zone. In addition, the width of exciton formation zone increases markedly with the trap density of EML increasing, and shows certain correlation with the dielectric constant of EML. The current modeling provides novel insights on optimizing EMLs towards wide exciton formation zone, helpful for extending operational stability of OLED.