Enhancing Thermoelectric Figure-of-Merit in Highly-Doped Conjugated Polymers

Highly doped conjugated polymers are promising thermoelectric (TE) materials because they combine solution processability, mechanical flexibility, and intrinsically low thermal conductivity. However, their TE figure-of-merit, ZT, is often limited by the trade-off between electrical conductivity and the Seebeck coefficient. While increasing the doping level enhances carrier concentration and conductivity, it generally lowers the Seebeck coefficient, restricting further improvement in the power factor. This presentation discusses strategies to enhance ZT in highly doped conjugated polymers by controlling doping-induced electronic states and polymer microstructure. Corresponding charge transport physics are also introduced, comparing various existing models, as well as proposed band-filling single-Gaussian (BFSG) model. By connecting molecular design, doping chemistry, and charge-transport physics, this talk aims to introduce design strategies for overcoming the conventional Seebeck-conductivity trade-off and developing high-ZT polymer TEs.