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

Single-walled carbon nanotube (SWCNTs-)-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 ( and ). Supramolecular functionalization of SWCNTs- with or induced charge-transfer interactions between them. Improved TE properties of the supramolecular hybrids (SWCNTs- and SWCNTs-) are attributed to increased charge-carrier concentration (electrical conductivity), interfacial phonon scattering (thermal conductivity), and energy difference between the transport and Fermi levels ( - ; Seebeck coefficient). SWCNTs- exhibited a ZT of 0.42 × 10 at 300 K, which is 350% larger than that of SWCNTs-. Furthermore, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (FTCNQ)-doped SWCNTs- showed the highest ZT value of 1.96 × 10 at 300 K among SWCNTs-/small organic molecule hybrids known until now. These results demonstrated that the supramolecular functionalization of SWCNTs- with small organic molecules could be useful for enhancement of TE performance and applications in wearable/flexible thermoelectrics.