In this report, we outline recent advances of thermoelectric n-type polymers that are suitable for printed thermoelectric generators (TEGs). In a first approach, the BiEDOT analogue BiEDOT-Cl was used to synthesize PEDOT-Cl by means of an oxidative polymerization process in the presence of FeTos3. The as-synthesized polymer exhibits a negative Seebeck coefficient and therefore shows n-type behavior. In addition, this polymer shows rheological properties suitable for printing. This paves the way for the integration in printed thermoelectric devices, which enables a dramatic boost of the expected power output in combination with a p-type polymer.
In this report, we present new routes and synthetic strategies towards the development of an n-type material, which meet the requirements for application in TEGs. Thereby we focused on heteroazulenes and we able to synthesize two new monomers CETO and F2-CETO as well as polymers P1-P4. Their characterization is ongoing regarding stability, doping mechanism and optoelectronic properties.