Abstract
Using nonequilibrium molecular dynamics simulations and nonequilibrium Green's function method, we investigate the thermoelectric properties of a series of zigzag and chiral carbon nanotubes which exhibit interesting diameter and chirality dependence. Our calculated results indicate that these carbon nanotubes could have higher ZT values at appropriate carrier concentration and operating temperature. Moreover, their thermoelectric performance can be significantly enhanced via isotope substitution, isoelectronic impurities, and hydrogen adsorption. It is thus reasonable to expect that carbon nanotubes may be promising candidates for high-performance thermoelectric materials.
Highlights
As it can directly convert waste heat into electric power, thermoelectric material is expected to be one of the promising candidates to meet the challenge of energy crisis
An ideal thermoelectric material requires glass-like thermal transport and crystal-like electronic properties [1], i.e., one should try to improve the ZT value by increasing the power factor [S2s] and/ or decreasing the thermal conductivity ( = e + p) at an appropriate temperature
We begin with the phonon transport of these CNTs using the NEMD simulations, where the phonon-induced thermal conductivity [p] is calculated according to Fourier’s law κp
Summary
As it can directly convert waste heat into electric power, thermoelectric material is expected to be one of the promising candidates to meet the challenge of energy crisis. An ideal thermoelectric material requires glass-like thermal transport and crystal-like electronic properties [1], i.e., one should try to improve the ZT value by increasing the power factor [S2s] and/ or decreasing the thermal conductivity ( = e + p) at an appropriate temperature. Such a task is usually very difficult since there is a strong correlation of those transport coefficients according to the WiedemannFranz law [2]. The mixing rate of the electronic Hamiltonian is set as 0.1, and the convergent criterion for the total energy is 4 × 10-5eV
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