Enhanced Thermoelectric Properties of Boron-Substituted Single-Walled Carbon Nanotube Films

Abstract

Atomic doping is the most fundamental approach to modulating the transport properties of carbon nanotubes. In this paper, we demonstrate the enhanced thermoelectric properties of boron-substituted single-walled carbon nanotube (B-SWCNT) films. The developed two-step synthesis of large quantities of B-SWCNTs readily enables the measurements of thermoelectricity of bulk B-SWCNT films. Complementary structural characterization implies the unique configuration of boron atoms at the doping sites of SWCNTs, successfully enabling carrier doping to SWCNTs. The developed boron substitution, in combination with chemical doping, is found to substantially improve the thermoelectric properties.

The Impacts of Polyisoprene Physical Interactions on Sorting of Single‐Wall Carbon Nanotubes

“…CVD synthesized SWCNTs d ≤ 2.0 nm following the previously reported procedure. [22,27] PFO M w 11 800 g mol −1 (PFO 12k ), PI M w 25 000 g mol −1 , and PFO 12k -b-PI with different PI monomer units were synthesized following the procedure reported in the authors' previous literature. [28] Sorting Procedure: 2 mg SWCNTs (d ≤ 1.0 nm & ≤ 2.0 nm) and 10 mL of toluene were used in all the experiments, but each polymer was controlled at the same concentration of ≈0.0024 mol L −1 .…”

Boron-Doped Single-Walled Carbon Nanotubes with Enhanced Thermoelectric Power Factor for Flexible Thermoelectric Devices

“…27 Very recently, the power factor, S 2 σ of SWCNT films has been improved via after-synthesis boron doping. 29 However, the TE effect of substitutional boron doping on SWCNTs is still unclear. For example, the atomic dopants increase the charge carrier number in nanotubes but also cause charge carrier scattering at the "defect" sites during TE transport processes.…”

“…By tuning the charge carrier concentration, chemical doping in SWCNTs modulates the Seebeck coefficient, S , and electrical conductivity, σ, of SWCNTs and significantly improves their TE power factor, S 2 σ . Currently, chemical doping in SWCNTs refers to charge transfer doping with the molecular/polymeric dopants chemisorbed on or encapsulated in the nanotubes. − , However, the efficiency of molecularly doping in carbon nanotubes is low and this necessitates employing dopant concentrations on the order of percent in practical applications. ,, Such bulky dopants may hinder the carrier transport across the nanotube–nanotube junctions, resulting in unsatisfactory σ values of the doped SWCNT networks. , Besides, the vulnerable organic dopants (degeneration at atmospheric condition/decomposition above 200 °C) narrow the operating range of the doped SWCNTs during processing or practical applications. − Substitutional doping is an alternative chemical doping scheme for SWCNTs, where heteroatoms (e.g., boron and nitrogen) substitute for the carbon in sp 2 lattice. , Thanks to the covalent interaction between the dopant and host atoms, a small amount of atomic dopants could efficiently increase the charge carrier number in SWCNTs and the resulted doped SWCNTs would have high structural stability. , To date, heteroatoms, such as nitrogen, boron, sulfur, silicon, and phosphorus, have been doped into carbon nanotubes, but atomically doped SWCNTs are rarely reported in the context of TE energy conversion applications. − …”

Carbon-Defect-Driven Boron Carbide for Dual-Modal NIR-II/Photoacoustic Imaging and Photothermal Therapy

“…The strong peak in the C 1s spectral region as well confirm the existence of a large number of carbon defects in the B 4 C@C nanosheets. The C 1s peaks located at 284.7 and 285.6 eV are assigned to the sp 2 carbon atoms and sp 3 carbon atoms, respectively (Figures S10 and S11). This further demonstrates that there are more carbon defects existing in B 4 C@C. The HRTEM results show that the rich defects in B 4 C@C may be caused by the interaction between the B 4 C and carbon layers.…”