Characterization and Comparison of Two Organic Mixed Ion-Electron Conductors
Semiconducting polymers, notably mixed ion electron conductors, have great promise for flexible and lightweight wearable devices that could integrate biology to electronics. The mechanisms for conduction in these materials are yet not fully understood, complicating the optimization of these materials for relevant applications. Here, we study two such polymers, poly(3,4-dioxythiophene-ethylene glycol) (ProDOT) and poly(thiophene-tetraethylene glycol) (P(g42T-T)), using characterization methods including UV-visible spectroscopy, DC conductivity and electrochemical impedance spectroscopy, grazing incidence wide angle x-ray spectroscopy, and mass uptake of water and dopant. Both of the polymers redshift upon doping, and develop polarons of similar energies. Due to their slightly different structures, the two polymers exhibit different structural changes and mixed ionic-electronic conduction upon doping. Future work will include a more complete comparison of the two polymers to develop an understanding of the role of side chain concentration and position along the backbone in ionic and electronic conduction and morphology.