Promoting the Thermoelectric Performance of Single-Walled Carbon Nanotubes by Inserting Discotic Liquid-Crystal Molecules

Single-walled carbon nanotubes (SWCNTs) are desirable flexible thermoelectric materials in applications of large-scale low-grade thermal energy. However, weak Seebeck coefficients of SWCNTs around room temperature limit their development as a flexible power generator. In this work, we significantly improve the Seebeck coefficients of SWCNT-based composites by integrating the discotic liquid-crystal 2,3,6,7,10,11-hexakis­(hexyloxy) triphenylene (HAT6) through the energy-filtering effect. The Seebeck coefficients of SWCNT/HAT6 composite films are about more than twice that of the pristine SWCNT films, and a maximum power factor of 408.23 ± 48.96 μW m–1 K–2 is achieved at room temperature, which is one of the highest values among organic small-molecule-based thermoelectric composites reported so far. The flexible power generator based on p-type SWCNT/HAT6 films is first assembled. An outstanding power density of 0.64 μW cm–2 with a thermoelectric voltage of 17.64 mV at a temperature gradient of 56 K is achieved. This study demonstrates that SWCNT/discotic liquid-crystal composites show great promise in thermoelectric (TE) materials and open a new avenue for the development of TE devices.