Effects of the active region thickness on the exciton generation mechanisms in polymer light emitting diodes

摘要

In this study, we investigate the influence of the active region thickness on the device characteristics parameters in single layer polymeric light emitting diode (PLED). Calculation of the key characteristic parameters versus layer thickness has been done at four different thicknesses that consist of 50, 80, 100 and 120 nm. We perform the analysis of the PLED with the drift-diffusion model, and the current and voltage thickness dependency. Finite element method has been taken into account to investigate active region thickness effects on the exciton generation rate versus distance from anode and also short time after injection of carriers in the polymer light emitting diode. In fact by decreasing the layer thickness, charge carrier distributions are changed in the organic material and concentrations of them are increased and whereby the probability for formation of excitons is increased, as well. Simulation results shown that thickness of active region has impressive effects on the electrical properties of the devices that resulted from the location of exciton generation along the active organic region. (C) 2015 Elsevier GmbH. All rights reserved.