Closely Packed Polypyrroles via Ionic Cross-Linking: Correlation of Molecular Structure-Morphology-Thermoelectric Properties

Juhyung Park, Yeran Lee, Miso Kim, Yungeun Kim, Ayushi Tripathi, Young Wan Kwon, Jeonghun Kwak, Han Young Woo

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


A series of ionically interconnected polypyrrole (PPy) films are fabricated through two-monomer-connected-precursor polymerization by varying diacid linkers, thereby significantly influencing the crystalline morphology and electrical properties. The structure obtained using 1,5-napthalenedisulfonic acid (PPy-Nap) as a fused aromatic linker exhibits a higher electrical conductivity (∼78 S cm-1) than that (6.7 S cm-1) without a linker (PPy-ref). Cryogenic conductivity measurements reveal that the percolation carrier transport barrier of PPy-Nap is significantly smaller than that of PPy-ref, and the calculated carrier mobility of PPy-Nap is ∼5 times higher compared to PPy-ref. The carrier transport characteristics show a good agreement with morphological data by 2D grazing-incidence X-ray scattering. All PPys have similar doped charge carrier concentrations and, thus, similar Seebeck coefficients (5-8 μV K-1) but very different electrical conductivities. Consequently, PPy-Nap exhibits a higher power factor than that of PPy-ref (0.21 vs 0.043 μW m-1 K-2). The results show that the trade-off relationship between the Seebeck coefficient and electrical conductivity can be overcome by improving crystalline morphology and carrier transport. Thus, both the electrical conductivities and thermoelectric power factors can be improved with maintaining the Seebeck coefficients by enhancing the ordered conductive domains and carrier mobility while maintaining the doping level.

Original languageEnglish
Pages (from-to)1110-1119
Number of pages10
JournalACS Applied Materials and Interfaces
Issue number1
Publication statusPublished - 2020 Jan 8


  • Seebeck coefficient
  • conductivity
  • morphology
  • organic thermoelectric
  • polypyrroles

ASJC Scopus subject areas

  • Materials Science(all)


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