Supramolecular Functionalization for Improving Thermoelectric Properties of Single-Walled Carbon Nanotubes-Small Organic Molecule Hybrids

Jae Gyu Jang; Sun Young Woo; Hwankyu Lee; Eunji Lee; Sung Hyun Kim; Jong-In Hong

doi:10.1021/acsami.0c13810

Supramolecular Functionalization for Improving Thermoelectric Properties of Single-Walled Carbon Nanotubes-Small Organic Molecule Hybrids

ACS Appl Mater Interfaces. 2020 Nov 18;12(46):51387-51396. doi: 10.1021/acsami.0c13810. Epub 2020 Nov 9.

Authors

Jae Gyu Jang¹, Sun Young Woo², Hwankyu Lee², Eunji Lee³, Sung Hyun Kim⁴, Jong-In Hong¹

Affiliations

¹ Department of Chemistry, Seoul National University, Seoul 08826, Korea.
² Department of Chemical Engineering, Dankook University, Yongin 448-701, Korea.
³ School of Materials Science and Technology, Gwangju Institute of Science and Technology, Gwangju 61005, Korea.
⁴ Department of Carbon Convergence Engineering, Wonkwang University, Iksan 54538, Korea.

PMID: 33166113
DOI: 10.1021/acsami.0c13810

Abstract

Single-walled carbon nanotube (SWCNTs-P)-small organic molecule hybrid materials are promising candidates for achieving high thermoelectric (TE) performance. In this study, we synthesized rod-coil amphiphilic molecules, that is, tri(ethylene oxide) chain-attached bis(bithiophenyl)-terphenyl derivatives (1 and 2). Supramolecular functionalization of SWCNTs-P with 1 or 2 induced charge-transfer interactions between them. Improved TE properties of the supramolecular hybrids (SWCNTs-1 and SWCNTs-2) are attributed to increased charge-carrier concentration (electrical conductivity), interfacial phonon scattering (thermal conductivity), and energy difference between the transport and Fermi levels (E_Tr - E_F; Seebeck coefficient). SWCNTs-2 exhibited a ZT of 0.42 × 10^-2 at 300 K, which is 350% larger than that of SWCNTs-P. Furthermore, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F₄TCNQ)-doped SWCNTs-2 showed the highest ZT value of 1.96 × 10^-2 at 300 K among SWCNTs-P/small organic molecule hybrids known until now. These results demonstrated that the supramolecular functionalization of SWCNTs-P with small organic molecules could be useful for enhancement of TE performance and applications in wearable/flexible thermoelectrics.

Keywords: charge-transfer interaction; single-walled carbon nanotubes; small organic molecule; supramolecular functionalization; thermoelectric properties.