Balancing Charge Storage and Mobility in an Oligo(Ether) Functionalized Dioxythiophene Copolymer for Organic‐ and Aqueous‐ Based Electrochemical Devices and Transistors

Abstract This work presents a soluble oligo(ether)‐functionalized propylenedioxythiophene (ProDOT)‐based copolymer as a versatile platform for a range of high‐performance electrochemical devices, including organic electrochemical transistors (OECTs), electrochromic displays, and energy‐storage devices. This polymer exhibits dual electroactivity in both aqueous and organic electrolyte systems, redox stability for thousands of redox cycles, and charge‐storage capacity exceeding 80 F g −1 . As an electrochrome, this material undergoes full colored‐to‐colorless optical transitions on rapid time scales ( 70%). Incorporation of the polymer into OECTs yields accumulation‐mode devices with an I ON/OFF current ratio of 10 5 , high transconductance without post‐treatments, as well as competitive hole mobility and volumetric capacitance, making it an attractive candidate for biosensing applications. In addition to being the first ProDOT‐based OECT active material reported to date, this is also the first reported OECT material synthesized via direct(hetero)arylation polymerization, which is a highly favorable polymerization method when compared to commonly used Stille cross‐coupling. This work provides a demonstration of how a single ProDOT‐based polymer, prepared using benign polymerization chemistry and functionalized with highly polar side chains, can be used to access a range of highly desirable properties and performance metrics relevant to electrochemical, optical, and bioelectronic applications.