Pedot:Tos Electronic And Thermoelectric Properties: Lessons From Two Polymerization Processes

In the landscape of pi-conjugated polymers, poly(3,4-ethylenedioxythiophene) doped with iron(iii) p-toluenesulfonate (PEDOT:Tos) has shown promise as a thermoelectric material for near room temperature applications. Such properties are inherent to its semi-metallic nature when optimally doped leading to high electrical conductivity and a relatively good Seebeck coefficient. Nevertheless, the final thermoelectric properties of PEDOT:Tos are highly influenced by the polymerization pathways and a thorough understanding of the interplay between polymerization processes and thermoelectric properties is needed. Here, PEDOT:Tos thin films with a doping level of 22 +/- 2% were produced by in situ polymerization and vapor-phase polymerization and a comparative study was performed in order to investigate the subtle correlations between morphological features and electronic signatures for both types of samples. Accordingly, optimized in situ polymerized PEDOT:Tos films were demonstrated to exhibit higher electrical conductivities (up to 4398 +/- 68 S cm(-1)) and power factors (up to 148 +/- 37 mu W m(-1) K-2), highlighting the importance of the polymerization process on the final thermoelectric properties.