Thickness-dependent thermoelectric power factor of polymer-functionalized semiconducting carbon nanotube thin films

Abstract

The effects of polymer structures on the thermoelectric properties of polymer-wrapped semiconducting carbon nanotubes have yet to be clarified for elucidating intrinsic transport properties. We systematically investigate thickness dependence of thermoelectric transport in thin films containing networks of conjugated polymer-wrapped semiconducting carbon nanotubes. Well-controlled doping experiments suggest that the doping homogeneity and then in-plane electrical conductivity significantly depend on film thickness and polymer species. This understanding leads to achieving thermoelectric power factors as high as 412 μW m−1 K−2 in thin carbon nanotube films. This work presents a standard platform for investigating the thermoelectric properties of nanotubes.

Unconventional Thermoelectric Materials for Energy Harvesting and Sensing Applications

“…9,235,252,253 Nonoguchi et al demonstrated that the plasmon resonance of free charge carriers in the infrared can also be used to systematically track relative carrier density in s-SWCNTs (Figure 21c). 254 While most molecular doping strategies do not modify the Fermi level strongly enough to quench the relatively high-energy excitonic transitions of m-SWCNTs, 255 the plasmon resonance intensity can report on systematic changes to the carrier density in m-SWCNTs. 256 However, electrostatic gating has been shown to be effective in modulating the Fermi level to a large enough degree to quench m-SWCNT excitonic transitions (Figure 21d,e), and the doping-induced tuning of the Fermi level increases the conductivity for both sand m-SWCNTs, as shown in Figure 21f,g for electrostatic doping of m-SWCNTs.…”

“…200 nm thick films. 254 Doping also appears to lower the thermal conductivity, 9,252 although further studies are needed to determine the precise mechanism at play. With respect to stability, s-SWCNT networks tend to be less stable to environmental degradation of n-type conductivity than their mixed and metallic counterparts.…”

“…(c) Plasma-torch s-SWCNTs progressively doped with AgTFSI, showing that the plasma resonance (PR) grows in as the S 11 is quenched. Reproduced with permission from ref . Copyright 2018 Taylor & Francis.…”

“…Nonoguchi et al demonstrated that the plasmon resonance of free charge carriers in the infrared can also be used to systematically track relative carrier density in s-SWCNTs (Figure c) . While most molecular doping strategies do not modify the Fermi level strongly enough to quench the relatively high-energy excitonic transitions of m-SWCNTs, the plasmon resonance intensity can report on systematic changes to the carrier density in m-SWCNTs .…”

Series Photothermoelectric Coupling Between Two Composite Materials for a Freely Attachable Broadband Imaging Sheet

“…[ 7 ] Among these candidates, randomly stacked CNT films demonstrate remarkable properties. A large Seebeck coefficient over 200 μV K −1 has been reported in enriched semiconducting CNT films, [ 8–10 ] and a larger value of 2500 μV K −1 has been well theorized in individual semiconducting CNTs with small diameters. [ 11 ] Simultaneously, CNT film‐based materials exhibit excellent broadband photoabsorption characteristics, [ 12 ] flexibility, [ 13 ] mechanical strength, [ 14 ] and corrosion resistance, [ 15 ] potentially leading to promising PTE photomonitoring applications.…”