Synergistic Impacts of Electrolyte Adsorption on the Thermoelectric Properties of Single-Walled Carbon Nanotubes

Single-walled carbon nanotubes are promising candidates for light-weight and flexible energy materials. Recently, the thermoelectric properties of single-walled carbon nanotubes have been dramatically improved by ionic liquid addition; however, controlling factors remain unsolved. Here the thermoelectric properties of single-walled carbon nanotubes enhanced by electrolytes are investigated. Complementary characterization with absorption, Raman, and X-ray photoelectron spectroscopy reveals that shallow hole doping plays a partial role in the enhanced electrical conductivity. The molecular factors controlling the thermoelectric properties of carbon nanotubes are systematically investigated in terms of the ionic functionalities of ionic liquids. It is revealed that appropriate ionic liquids show a synergistic enhancement in conductivity and the Seebeck coefficient. The discovery of significantly precise doping enables the generation of thermoelectric power factor exceeding 460 µW m^-1 K^-2 .

Air-tolerant Fabrication and Enhanced Thermoelectric Performance of n-Type Single-walled Carbon Nanotubes Encapsulating 1,1'-Bis(diphenylphosphino)ferrocene

The thermally-triggered n-type doping of single-walled carbon nanotubes is demonstrated using 1,1'-bis(diphenylphosphino)ferrocene, a novel n-type dopant. Through a simple thermal vacuum process, the phosphine compounds are moderately encapsulated inside single-walled carbon nanotubes. The encapsulation into SWNTs is carefully characterized using Raman/X-ray spectroscopy and transmission electron microscopy. This easy-to-handle doping with air-stable precursors for n-type SWNTs enables the large-scale fabrication of thermoelectric materials showing an excellent power factor exceeding approximately 240 μW mK(-2) .

Solid-state, individual dispersion of single-walled carbon nanotubes in ionic liquid-derived polymers and its impact on thermoelectric properties

The enhanced thermoelectric properties of single-walled carbon nanotubes exfoliated in an ionic liquid polymer is reported.

Dispersion of Synthetic MoS2 Flakes and Their Spontaneous Adsorption on Single-Walled Carbon Nanotubes

Noncovalent interactions play a critical, but not yet understood, role in enhancing the thermoelectric properties of carbon nanotube composites. We herein report the dispersion of synthetic MoS₂ flakes and their self-assembly with single-walled carbon nanotubes via in-plane and multipoint S-π interactions. The hybridization of MoS₂ and carbon nanotubes leads to improved electrical and thermoelectric transport, and resulted in a tenfold enhancement of the thermoelectric figure-of-merit of nanotube-based films. The present technique could contribute to advancing the flexible energy materials that harvest abundant waste heat.