Fabrication and simulation of polyfluorene-based organic light-emitting diodes

We demonstrate the fabrication of green and blue conjugated-polymer light-emitting diodes with aluminium as the cathode electrode. In addition, we examine the characteristics of the devices using a numerical model. The model considers the localized nature of carriers in light-emitting polymers and also the hopping of carriers from the metal electrodes into the localized electronic states of the organic solid. We use the model to simulate the current-voltage-brightness characteristics of the two devices. We show this theoretical approach yields reasonable results even for our devices with high barrier contacts. Also, we investigate the carrier distribution and recombination profile within the emissive layer.