Optimizing Electrical Conductivity of PEDOT:PSS Films: A Systematic Study of Individual and Combined Enhancement Techniques

Abstract This study focuses on crafting organic conductive electrodes for flexible substrate-based organic electronics, exploring techniques to enhance PEDOT:PSS film conductivity, including acid treatments, noble and non-noble metal nanoparticle doping, multiple layer depositions, and mono-layer graphene and graphene nanoplatelets insertion. These methods are systematically investigated, both individually and in combination, to optimize enhancement and provide engineering flexibility for various applications. The optimized process prioritizes PEDOT:PSS multilayer depositions and nitric acid treatment, proving more effective and cost-efficient. The research details a process of rendering PEDOT:PSS polymer films highly conductive, highlighting their patterning abilities and robust adhesion to oxidized Si wafers and flexible substrates. Adhesion is accomplished with oxygen plasma treatment, and patterning involves an Ag sacrificial layer, PEDOT:PSS etching, and Ag island removal. Enhanced electrical conductivity is achieved through multiple PEDOT:PSS depositions without significant thickness increase. The paper explores doping PEDOT:PSS with metal nanoparticles like Cu and Ag, in both bulk and topical applications. Compared to a single-layer PEDOT:PSS of the same thickness, the optimized multilayer polymer stack, treated with nitric acid, reduces sheet resistance from 1 MΩ/sq to 6.7 Ω/sq. The study also addresses film aging and ways to mitigate reliability effects induced by the ambient environment.