Numerical study of hybrid quantum dot light-emitting diode with different concentration of quantum dots in the emissive layer

In this study, a model for numerical simulation of carrier transport mechanism in the hybrid quantum dot light-emitting diodes (QD-LEDs) is presented. The carrier mobility in the polymer layer doped with quantum dots (QDs) was calculated by a proposed hopping mobility, which is a concentration-dependent mobility model based on the Gaussian distribution of density-of-states and the effective transport energy models. A QD-LED structure based on PVK:CdSe-QDs blend as the emissive layer with different QD concentrations were fabricated and their current density versus voltage (J-V) characteristic were measured. The numerical results were compared with experimental data, which indicates the ability of the proposed mobility model to describe the general trend of the electrical characteristics of the devices. Then, the exciton density profiles of the devices were extracted based on the continuity equation for singlet and triplet excitons, and the corresponding luminance characteristics of the devices were calculated. The results of the electrical and optical characteristics show that there is an optimal concentration for the QDs in the emissive layer of the QD-LEDs.