Observation of Weak Counterion Size Dependence of Thermoelectric Transport in Ion Exchange Doped Conducting Polymers Across a Wide Range of Conductivities

Chen Chen, Ian E. Jacobs, Keehoon Kang, Yue Lin, Cameron Jellett, Boseok Kang, Seon Baek Lee, Yuxuan Huang, Mohammad BaloochQarai, Raja Ghosh, Martin Statz, William Wood, Xinglong Ren, Dion Tjhe, Yuanhui Sun, Xiaojian She, Yuanyuan Hu, Lang Jiang, Frank C. Spano, Iain McCullochHenning Sirringhaus

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Conducting polymers are of interest for a broad range of applications from bioelectronics to thermoelectrics. The factors that govern their complex charge transport physics include the structural disorder present in these highly doped polymer films and the Coulombic interactions between the electronic charge carriers and the dopant counterions. Previous studies have shown that at low doping levels carriers are strongly trapped in the vicinity of the counterions, while at high doping levels charge transport is not limited by Coulombic trapping, which manifests itself in the conductivity being independent of the size of the dopant counterion. Here a recently developed ion exchange doping method is used to investigate the ion size dependence of a semicrystalline polythiophene-based model system across a wide range of conductivities. It is found that the regime in which the charge and thermoelectric transport is not or only weakly dependent on ion size, extends to surprisingly low conductivities. This surprising observation is explained by a heterogeneous doping that involves doping of the amorphous domains to high doping levels first before doping of the ordered, crystalline domains occurs. The study provides new insights into how the thermoelectric physics of conducting polymers evolves as a function of doping level.

Original languageEnglish (US)
Article number2202797
JournalAdvanced Energy Materials
Volume13
Issue number9
DOIs
StatePublished - Mar 3 2023
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • General Materials Science

Keywords

  • counterion effect
  • doping
  • organic electronics
  • semicrystalline polymers
  • thermoelectrics

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