Thermoelectric properties of sorted semiconducting single-walled carbon nanotube sheets

Wenxin Huang; Eriko Tokunaga; Yuki Nakashima; Tsuyohiko Fujigaya

doi:10.1080/14686996.2019.1567107

Thermoelectric properties of sorted semiconducting single-walled carbon nanotube sheets

Sci Technol Adv Mater. 2019 Mar 1;20(1):97-104. doi: 10.1080/14686996.2019.1567107. eCollection 2019.

Authors

Wenxin Huang¹, Eriko Tokunaga¹, Yuki Nakashima¹, Tsuyohiko Fujigaya^{1

2

3

4}

Affiliations

¹ Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, Fukuoka, Japan.
² The World Premier International Research Center Initiative, International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, Fukuoka, Japan.
³ Japan Science and Technology Agency (JST-PRESTO), Kawaguchi, Japan.
⁴ Center for Molecular Systems (CMS), Kyushu University, Fukuoka, Japan.

Abstract

Single-walled carbon nanotubes (SWNTs), especially their semiconducting type, are promising thermoelectric (TE) materials due to their high Seebeck coefficient. In this study, the in-plane Seebeck coefficient (S), electrical conductivity (σ), and thermal conductivity (κ) of sorted semiconducting SWNT (s-SWNT) free-standing sheets with different s-SWNT purities are measured to determine the figure of merit ZT. We find that the ZT value of the sheets increases with increasing s-SWNT purity, mainly due to an increase in Seebeck coefficient while the thermal conductivity remaining constant, which experimentally proved the superiority of the high purity s-SWNT as TE materials for the first time. In addition, from the comparison between sorted and unsorted SWNT sheets, it is recognized that the difference of ZT between unsorted SWNT and high-purity s-SWNT sheet is not remarkable, which suggests the control of carrier density is necessary to further clarify the superiority of SWNT sorting for TE applications.

Keywords: 104 Carbon and related materials; 105 Low-Dimension (1D/2D) materials; 206 Energy conversion / transport / storage / recovery; 210 Thermoelectronics / Thermal transport / insulators; 50 Energy Materials; Seebeck coefficient; Semiconducting carbon nanotubes; figure of merit; thermal conductivity; thermoelectric conversion.

Grants and funding

This work was supported by the Nanotechnology Platform Project, from the Ministry of Education, Culture, Sports, Science and Technology, Japan, KAKENHI [No. JP18H01816, JP16K14084, and JP16H06056]; Japan Society for the Promotion of Science, and PRESTO [JPMJPR15R6].