Variable Resolution Coarse-Graining of Ion-Coupled Electron Transport in Electrochemically Active Polymers

Conducting polymers that exhibit reversible mass and ion exchange with aqueous media have potential for sensing applications when implemented in organic electrochemical transistors (OECTs). However, the degree to which ion motion is coupled with electron transport and morphology changes, and the range of polymer chemistries that can exhibit and be optimized for electrochemical response in aqueous media is unknown. To address these challenges we have developed the first variable resolution model of hydrated PEDOT:PSS, the archetypical electrochemically active system, with several simple salts. Using this variable resolution model we are able to characterize both long-timescale morphology reorganizations and the corresponding short-timescale evolution of the conducting polymer electronic structure and develop design rules for optimal doping and hydration levels in PEDOT-based systems. The generality of this approach creates an opportunity to establish to what degree PEDOT:PSS is representative of other OECT polymers and address the lack of materials diversity in OECT applications.