Influence of fabrication process on the performance of light-emitting diodes

We have investigated the influence of device fabrication process on the performance of poly (p-phenylene vinylene) (PPV) and poly (N-vinyl carbazole) (PVK) blended with triphenylamine (TPA) (PVK:TPA)-based light-emitting diodes by constructing various devices with different structures and treated under different conditions. Thermal treatments make modifications to the contacts, affect the electrical properties of the polymer, change the rectification ratio by orders of magnitude, and affect the efficiency of the devices. Partially converted PPV improved the efficiency due to short conjugated length, but results in the stability of the devices to be compromised. Structure of PVK:TPA/PPV unbalances the injection of holes and electrons, but lowers the turn-on voltage.