Boosting the Thermoelectric Performance of the Doped DPP-EDOT Conjugated Polymer by Incorporating an Ionic Additive

Yilin Song; Xiaojuan Dai; Ye Zou; Cheng Li; Chong-An Di; Deqing Zhang; Daoben Zhu

doi:10.1002/smll.202300231

Boosting the Thermoelectric Performance of the Doped DPP-EDOT Conjugated Polymer by Incorporating an Ionic Additive

Small. 2023 Jul;19(29):e2300231. doi: 10.1002/smll.202300231. Epub 2023 Apr 7.

Authors

Yilin Song^{1

2}, Xiaojuan Dai^{1

2}, Ye Zou^{1

2}, Cheng Li^{1

2}, Chong-An Di^{1

2}, Deqing Zhang^{1

2}, Daoben Zhu^{1

2}

Affiliations

¹ Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
² School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.

PMID: 37026675
DOI: 10.1002/smll.202300231

Abstract

The thermoelectric (TE) performance of organic materials is limited by the coupling of Seebeck coefficient and electrical conductivity. Herein a new strategy is reported to boost the Seebeck coefficient of conjugated polymer without significantly reducing the electrical conductivity by incorporation of an ionic additive DPPNMe₃ Br. The doped polymer PDPP-EDOT thin film exhibits high electrical conductivity up to 1377 ± 109 S cm^-1 but low Seebeck coefficient below 30 µV K^-1 and a maximum power factor of 59 ± 10 µW m^-1 K^-2 . Interestingly, incorporation of small amount (at a molar ratio of 1:30) of DPPNMe₃ Br into PDPP-EDOT results in the significant enhancement of Seebeck coefficient along with the slight decrease of electrical conductivity after doping. Consequently, the power factor (PF) is boosted to 571 ± 38 µW m^-1 K^-2 and ZT reaches 0.28 ± 0.02 at 130 °C, which is among the highest for the reported organic TE materials. Based on the theoretical calculation, it is assumed that the enhancement of TE performance for the doped PDPP-EDOT by DPPNMe₃ Br is mainly attributed to the increase of energetic disorder for PDPP-EDOT.

Keywords: 3,4-ethlenedioxythiophene; diketopyrrolopyrrole; ionic additive; organic thermoelectric materials; polymer semiconductors.

Abstract

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