Improvement in the Performance and Stability of EL Devices by the Formation of Self-Assembled Layers of PEDOT and Polyelectrolytes on ITO Surface

Abstract

Self-assembled PEDOT layers were prepared on polyelectrolytes multilayers on an ITO surface using a layer-by-layer technique. The electroluminescence (EL) efficiencies of the devices were drastically enhanced by the addition of polyethyleneimine (PEI) and polyacrylic acid (PAA) bilayers between the ITO and self-assembled PEDOT layers. The presence of self-assembled PEDOT layers prior to the PEDOT spin-coated layers improved the interfacial contact by increasing the current density and system efficiency. Remarkably, the lifetime of the device was 60% longer than the one without the self-assemblies, which was attributed to the improvement in the interfacial contact, and the blocking of electrode corrosion and the migration of the indium components across the interfacial layers.