Synergistic Interactions in Sequential Process Doping of Polymer/Single-Walled Carbon Nanotube Nanocomposites for Enhanced n-Type Thermoelectric Performance

Po-Shen Lin; Jhih-Min Lin; Shih-Huang Tung; Tomoya Higashihara; Cheng-Liang Liu

doi:10.1002/smll.202306166

Synergistic Interactions in Sequential Process Doping of Polymer/Single-Walled Carbon Nanotube Nanocomposites for Enhanced n-Type Thermoelectric Performance

Small. 2024 Mar;20(9):e2306166. doi: 10.1002/smll.202306166. Epub 2023 Oct 17.

Authors

Po-Shen Lin¹, Jhih-Min Lin², Shih-Huang Tung³, Tomoya Higashihara⁴, Cheng-Liang Liu^{1

5}

Affiliations

¹ Department of Materials Science and Engineering, National Taiwan University, Taipei, 10617, Taiwan.
² National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan.
³ Institute of Polymer Science and Engineering, National Taiwan University, Taipei, 10617, Taiwan.
⁴ Department of Organic Materials Science, Graduate School of Organic Materials Science, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510, Japan.
⁵ Advanced Research Center for Green Materials Science and Technology, National Taiwan University, Taipei, 10617, Taiwan.

PMID: 37847895
DOI: 10.1002/smll.202306166

Abstract

This study focuses on the fabrication of nanocomposite thermoelectric devices by blending either a naphthalene-diimide (NDI)-based conjugated polymer (NDI-T1 or NDI-T2), or an isoindigo (IID)-based conjugated polymer (IID-T2), with single-walled carbon nanotubes (SWCNTs). This is followed by sequential process doping method with the small molecule 4-(2,3-dihydro-1,3-dimethyl-1H-benzimidazol-2-yl)-N,N-dimethylbenzenamine (N-DMBI) to provide the nanocomposite with n-type thermoelectric properties. Experiments in which the concentrations of the N-DMBI dopant are varied demonstrate the successful conversion of all three polymer/SWCNT nanocomposites from p-type to n-type behavior. Comprehensive spectroscopic, microstructural, and morphological analyses of the pristine polymers and the various N-DMBI-doped polymer/SWCNT nanocomposites are performed in order to gain insights into the effects of various interactions between the polymers and SWCNTs on the doping outcomes. Among the obtained nanocomposites, the NDI-T1/SWCNT exhibits the highest n-type Seebeck coefficient and power factor of -57.7 µV K^-1 and 240.6 µW m^-1 K^-2 , respectively. However, because the undoped NDI-T2/SWCNT exhibits a slightly higher p-type performance, an integral p-n thermoelectric generator is fabricated using the doped and undoped NDI-T2/SWCNT nanocomposite. This device is shown to provide an output power of 27.2 nW at a temperature difference of 20 K.

Keywords: carbon nanotubes; conjugated polymers; n-type doping; nanocomposites; thermoelectric.

Abstract

Grants and funding