Enhancing thermoelectric performance of single-walled carbon nanotube/reduced graphene oxide composites with small organic molecules as a novel additive

• Published in: New journal of chemistry Vol. 47; no. 47; pp. 21692 - 21699
• Main Authors: Jang, Jae Gyu, Kim, Tae-hoon, Kim, Sung Hyun, Hong, Jong-In
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 04.12.2023
• Subjects: Carrier transport; Figure of merit; Graphene; Imidazole; Organic chemistry; Reduction; Seebeck effect; Single wall carbon nanotubes; Thermal conductivity; Thermoelectricity; Transport properties
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d3nj03568a

A small organic molecule (SOM), 2,2′-(3,3′′-dihexyl-[2,2′:5′,2′′-terthiophene]-5,5′′-diyl)bis(1-octyl-1 H -phenanthro[9,10- d ]imidazole) ( 1 ), was utilised as an additive to intercalate with reduced graphene oxides (rGOs- 1 ) in a single walled-carbon nanotube (SWCNT) composite. The ternary composite formed by incorporating rGOs- 1 into the SWCNTs exhibited improvements in thermoelectric (TE) and carrier transport properties through the strong interfacial π-π interaction between the rGOs- 1 and SWCNTs. The SOM 1 hybridised with the SWCNT composite induced significant interfacial phonon scattering, resulting in a reduction in the thermal conductivity ( κ ) of the SWCNT composite with rGOs- 1 . As a result, the SWCNT composite incorporating rGOs- 1 demonstrated a simultaneous improvement of the Seebeck coefficient by 15% and a reduction in κ by 32%, resulting in an enhancement in the TE figure of merit (6.8 ± 0.7 × 10 −3 at 297 K), which was 2.3 times higher than that of the SWCNTs alone (2.9 ± 0.5 × 10 −3 ). Intercalating 1 into a composite of single-walled carbon nanotubes (SWCNTs) and reduced graphene oxides achieved a ZT over 6.8 × 10 −3 , 2.3 times higher than SWCNTs (2.9 × 10 −3 ), by improving Seebeck coefficient and reducing thermal conductivity.