Influence of the charge carrier mobility on the dynamic behavior and performance of the single-layer OLED

Abstract

In this paper, by solving the drift-diffusion and Poisson equations, a numerical simulation for single layer organic light emitting diode (OLED) has been presented. Finite element method has been taken into account in calculations and the effects of electron and hole mobilities on the electrical properties of OLEDs have been investigated. The influences of the hole and electron mobilities on the charge carrier and exciton generation rates in the terms of distance from anode and carrier injection time have been calculated and it was shown that by increasing the carrier mobilities, the carrier concentrations as well as exciton generation rate were increased. Charge distribution densities versus distance from anode for various electron and hole mobilities, have been calculated and it was found that due to high mobility of holes, the electron–hole recombination happens near the cathode. From the simulation results it was found that the mobility of electrons is the most important parameter, which decides directly about the transport of free carriers and the recombination in the organic material.