Thermoelectric PEDOT:PSS and single-walled carbon nanotubes composites for printing applications

Thermoelectric describes the interactions between temperature and voltage, i.e. a temperature difference is converted into usable electrical energy which is called Seebeck-Effect. Key parameters are the electrical conductivity s and the Seebeck-coefficient a which are combined in the Power-Factor (PF = a²·s) to express the efficiency of a thermoelectric material. It is desired to manufacture bendable or flexible thermoelectric generators (TEGs) by low-cost and large scale production techniques e.g. printing. Therefore, composites made of intrinsically conducting polymer and nanoparticles, especially carbon nanotubes, which are printable, are the focus of this work. The intrinsically conducting polymer, PEDOT:PSS doped with DMSO, was used in combination with different types of single-walled carbon nanotubes (SWCNT). The SWCNTs were mixed with various dispersants and then added to the PEDOT:PSS disperison. The composite dispersions with different amounts of SWCNTs were deposited by Spin-Coating and characterized. The results showed an increase of the Power-Factor by ~30% compared to pristine PEDOT:PSS. Furthermore the influence of the dispersants and the dispersing methods on PEDOT:PSS and SWCNTs were investigated.