Impact of Oligoether Side-Chain Length on the Thermoelectric Properties of a Polar Polythiophene

Mariavittoria Craighero, Jiali Guo, Sepideh Zokaei, Sophie Griggs, Junfu Tian, Jesika Asatryan, Joost Kimpel, Renee Kroon, Kai Xu, Juan Sebastian Reparaz, Jaime Martín, Iain McCulloch, Mariano Campoy-Quiles, Christian Müller

Research output: Contribution to journalReview articlepeer-review

1 Scopus citations


Conjugated polymers with oligoether side chains make up a promising class of thermoelectric materials. In this work, the impact of the side-chain length on the thermoelectric and mechanical properties of polythiophenes is investigated. Polymers with tri-, tetra-, or hexaethylene glycol side chains are compared, and the shortest length is found to result in thin films with the highest degree of order upon doping with the p-dopant 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ). As a result, a stiff material with an electrical conductivity of up to 830 ± 15 S cm-1 is obtained, resulting in a thermoelectric power factor of about 21 μW m-1 K-2 in the case of as-cast films. Aging at ambient conditions results in an initial decrease in thermoelectric properties but then yields a highly stable performance for at least 3 months, with values of about 200 S cm-1 and 5 μW m-1 K-2. Evidently, identification of the optimal side-chain length is an important criterion for the design of conjugated polymers for organic thermoelectrics.

Original languageEnglish (US)
Pages (from-to)2909-2916
Number of pages8
JournalACS Applied Electronic Materials
Issue number5
StatePublished - May 28 2024
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry
  • Electrochemistry


  • chemical doping
  • conjugated polymer
  • electrical conductivity
  • organic thermoelectrics
  • side-chain length


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