High-performance post-treatment-free PEDOT based thermoelectric with the establishment of long-range ordered conductive paths

In this work, post-treatment-free polymer hybrids, consisting of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and ionic liquids (ILs), were fabricated for the thermoelectric (TE) application. By optimizing the ILs' molar concentration (0-0.5 M) and chemical composition, that is varying the cyano-based anions coupled with 1-ethyl-3-methylimidazolium cations, a high TE performance (power factor of 190 mu W m(-1) K-2) was achieved. The excellent TE performance was attributed to the conductive network under the coupling effect of molecular structure (such as oxidation level, conformation and crystallization of PEDOT chains) and microstructure (long-range ordered conductive paths). Especially, the long-range conductive paths were proved to be made of rod-like microdomains, based on detailed structure analysis with micro-Fourier transform infrared spectroscopy and small-angle X-ray scattering. These paths enabled carrier transport among microdomains of PEDOT:PSS/IL hybrids. Moreover, the conductive network of PEDOT:PSS/IL hybrids showed good environmental and mechanical stability, enabling the fabrication of flexible TE generators.

Automated summary

Post-treatment-free polymer hybrids of PEDOT:PSS and ILs were fabricated for TE applications. By optimizing ILs' molar concentration and chemical composition, high TE performance was achieved due to the conductive network formed by molecular and microstructural factors. The conductive paths were shown to be made of rod-like microdomains, enabling carrier transport among microdomains. These hybrids also exhibited good environmental and mechanical stability for the fabrication of flexible TE generators.