Exploring the Interplay Between Microstructure Evolution, Polaron Formation and Charge Transport in OMIECs

Organic mixed ionic–electronic conductors (OMIECs) are a versatile class of soft materials, primarily conjugated polymers, that exhibit both ionic and electronic conductivity. This dual conductivity, combined with tunable chemistry, makes OMIECs highly attractive for applications in energy storage, neuromorphic computing, biosensors, and bioactuators. However, a key challenge remains in understanding the intricate dynamic interplay between electronic transport, ionic transport, and material structure during device operation.
In this work, we investigate how polymer side chains can be used to engineer the microstructure and control ion uptake across the polymer film, and, consequently, to tune the electronic transport properties. Using a suite of characterization techniques, including conductivity measurements, operando GIWAXS, and spectroelectrochemistry, we demonstrate how chemical modifications affect the polymer's crystalline microstructure and its dynamic behavior under electrochemical doping, impacting polaron formation and ultimately charge transport and device performance. Our results provide insights that will inform future design strategies for optimizing OMIECs.