Doped networks of semiconducting single-walled carbon nanotubes (s-SWCNTs) have recently demonstrated high thermoelectric (TE) power factors and figures of merit. Efforts to further improve the TE performance of s-SWCNT networks hinge upon deeper understanding of the mechanisms underlying charge transport. This study explores the dependence of conductivity, thermopower, and resulting TE power factor on carrier density and temperature in s-SWCNT networks. Careful control of charge-carrier density illustrates a distinct transition between transport that is limited by energetic barriers between nanotube bundles to an 'intrinsic' regime where these barriers are small enough to reveal the intrinsic transport mechanism of the nanotubes. Transport is activated in the s-SWCNT networks, although a critical survey of the literature demonstrates that the activation energies in s-SWCNT networks are appreciably smaller than typical semiconducting polymers. At high conductivity, transport behavior is consistent with deformation potential scattering. The analysis demonstrates that mitigation of the 'extrinsic' limitations to transport (e.g., inter-nanotube junctions), and the concomitant reduction of conductivity activation energies, can lead to at least a doubling of the TE power factor. Further comparison to prototypical semiconducting polymers demonstrates that this strategy likely represents a general design principle for improving the TE performance of organic materials.
Blackburn, Jeffrey L., Kang, Stephen D., Roos, Michael J., Norton-Baker, Brenna, Miller, Elisa M., & Ferguson, Andrew J. (2019). Intrinsic and Extrinsically Limited Thermoelectric Transport within Semiconducting Single-Walled Carbon Nanotube Networks. Advanced Electronic Materials, 5(11). https://doi.org/10.1002/aelm.201800910
Blackburn, Jeffrey L., Kang, Stephen D., Roos, Michael J., et al., "Intrinsic and Extrinsically Limited Thermoelectric Transport within Semiconducting Single-Walled Carbon Nanotube Networks," Advanced Electronic Materials 5, no. 11 (2019), https://doi.org/10.1002/aelm.201800910
@article{osti_1501658,
author = {Blackburn, Jeffrey L. and Kang, Stephen D. and Roos, Michael J. and Norton-Baker, Brenna and Miller, Elisa M. and Ferguson, Andrew J.},
title = {Intrinsic and Extrinsically Limited Thermoelectric Transport within Semiconducting Single-Walled Carbon Nanotube Networks},
annote = {Doped networks of semiconducting single-walled carbon nanotubes (s-SWCNTs) have recently demonstrated high thermoelectric (TE) power factors and figures of merit. Efforts to further improve the TE performance of s-SWCNT networks hinge upon deeper understanding of the mechanisms underlying charge transport. This study explores the dependence of conductivity, thermopower, and resulting TE power factor on carrier density and temperature in s-SWCNT networks. Careful control of charge-carrier density illustrates a distinct transition between transport that is limited by energetic barriers between nanotube bundles to an 'intrinsic' regime where these barriers are small enough to reveal the intrinsic transport mechanism of the nanotubes. Transport is activated in the s-SWCNT networks, although a critical survey of the literature demonstrates that the activation energies in s-SWCNT networks are appreciably smaller than typical semiconducting polymers. At high conductivity, transport behavior is consistent with deformation potential scattering. The analysis demonstrates that mitigation of the 'extrinsic' limitations to transport (e.g., inter-nanotube junctions), and the concomitant reduction of conductivity activation energies, can lead to at least a doubling of the TE power factor. Further comparison to prototypical semiconducting polymers demonstrates that this strategy likely represents a general design principle for improving the TE performance of organic materials.},
doi = {10.1002/aelm.201800910},
url = {https://www.osti.gov/biblio/1501658},
journal = {Advanced Electronic Materials},
issn = {ISSN 2199-160X},
number = {11},
volume = {5},
place = {United States},
publisher = {Wiley},
year = {2019},
month = {02}}