Temperature-Dependent Thermoelectric Transport in Polymer-Sorted Semiconducting Carbon Nanotube Networks with Different Diameter Distributions*

We report carrier density and temperature dependent field-effect mobility and on-chip Seebeck coeff. measurements of small diameter (6,5) (0.76 nm), ttmgb treated (6,5) and large diameter plasma torch (RN, 1.17-1.55 nm) SWCNT networks with different network densities to provide insights into their charge transport mechanisms and potential for thermoelectric applications. The Seebeck coeff. offers insights into transport energetics, potential contributions from electron-electron and electron-phonon interactions and the relative contributions of inter- versus intra-CNT transport.¹ A pure percolation theory and VRH description cannot explain both transport coefficients and instead intra-CNT transport depending on chirality needs to be considered as well. In the high network density regime, the density influences neither electric nor thermoelectric transport strongly, indicating both are dominated by tubes rather than tube-tube junctions. Despite generally lower mobilities, (6,5) SWCNTs show comparable power factors to RN networks. These findings provide design guidelines towards narrow DoS distr., large diameter SWCNT networks for both electronic and thermoelectric applications.²
[1] Statz, M. et al. Commun. Phys. 1, 16 (2018).
[2] Statz, M. et al., in prep. (2019).