Memristive response and electrochemical processes in polyaniline based organic devices

Abstract

We investigated in details the redox mechanism of an electrochemical two-terminal solid-state device with memory, otherwise named organic memristive device (OMD), by varying the composition of solid polyelectrolytes, the doping agents of the conducting polymer, and the material of the gate electrode. The switching mechanism resulted dependent on the presence of a redox active polymer with high conducting and low conducting states, the presence of a redox counter-reaction, and the ability to transport ions between the polymer and electrolyte phases. The memristive response was observed in hydrochloric acid doped and silver gated devices. The crucial role of the chloride ions and of the silver wire as gate electrode for the promotion of electrochemical reactions is demonstrated. The redox reactions occurring in OMD, the silver dissolution process and the redox reactions of PANI result to be tuned by silver chloride precipitation and ion migration into/out of the polymer matrix to compensate the excess of charges inside the film. The dopant anions are released from polymer network during its oxidation and deprotonation process. Our results, giving rise to a more detailed understanding of the mechanisms involved in redox gated memory devices, provide also a better identification and important details about the requirements for the conducting polymer, the redox counter reaction, and the polyelectrolyte for optimizing the development and fabrication of organic solid-state nonvolatile memory devices. • The redox mechanism of a conductive polymer in a solid-state device was investigated. • Different formulations of polymeric blends as well as the electrode materials were considered. • The current rectification was observed without the presence of any cation in the polyelectrolyte. • The memristive response was due to chloride acid in silver gated devices.