Controlling Resistive Switching Modes of Ferrocene-Containing Polyelectrolyte Layer-by-Layer Nanofilms

We propose controlling ion diffusion and electron hopping in a polymer-based resistive switching device consisting of ferrocene (Fc)-containing polyelectrolyte nanofilms as a switching layer and PEDOT:PSS films as a top electrode. The switching layer was fabricated onto ITO electrodes using the layer-by-layer (LbL) method of Fc-containing branched polyethyleneimine (bPEI-Fc) and poly(styrene sulfonate) (PSS). Current–voltage characteristics of the ITO|(bPEI-Fc/PSS) n |PEDOT:PSS device with a simple sandwich structure exhibited resistive switching and short-circuited behavior; the characteristics depended on the Fc contents and relative humidity. Cyclic voltammetry and electrochemical impedance spectroscopy measurements indicated that the interdistance between nearby Fc units and the polymer segment motion coupled with water penetration govern the current–voltage characteristics. This study elucidates unique features of polymer-based resistive switching devices, paving the way for neuromorphic and wearable electronics applications.