Tuning Mixed Ionic-Electronic Transport in PEDOT:PSS

Organic mixed ionic-electronic conductors (OMIECs)—conjugated polymers that can transport and capacitively store both ionic and electronic charges—are fundamental to the development of bioelectronics, energy storage, and neuromorphic computing. In organic electrochemical transistors (OECTs) in particular, OMIECs are used in the channel of the transistor to generate large currents under small voltage bias, making them attractive amplifiers for biosensing applications. While new OMIECs are regularly reported, the most commonly used material is the polyelectrolyte complex PEDOT:PSS. This material is commercially available as a dispersion in water and provides excellent performance in OECT after a variety of post-treatments. In this talk, I will share how our laboratory uses controlled radical polymerizations to precisely synthesize PSS and its derivatives towards a better understanding of structure-property relationships in PEDOT:PSS. I will also present a novel strategy to ensure that the films remain stable in water under repeated cycling operations by using an adhesion monolayer between the substrate and the PEDOT:PSS films.