Enhanced thermoelectric figure of merit in polycrystalline carbon nanostructures
Physical Review B 92, 035418 (2015).
T. Lehmann, D. A. Ryndyk, and G. Cuniberti.
https://doi.org/10.1103/PhysRevB.92.035418

Grain boundaries are commonly observed in carbon nanostructures, but their influence on thermal and electric properties is still not completely understood. Using a combined approach of density functional tight-binding theory and nonequilibrium Green functions we investigate electron and phonon transport in carbon-based systems. In this work, quantum transport and thermoelectric properties are summarized for graphene sheets, graphene nanoribbons, and carbon nanotubes with a variety of grain boundary types in a wide temperature range. Motivated by previous findings that disorder scatters phonons more effectively than electrons, a significant improvement in the thermoelectric performance for polycrystalline systems is expected. As the effect is marginally sensitive to the grain boundary type, we demonstrate that grain boundaries are a viable tool to greatly enhance the figure of merit, paving the way for the design of new thermoelectric materials.

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Enhanced thermoelectric figure of merit in polycrystalline carbon nanostructures
Physical Review B 92, 035418 (2015).
T. Lehmann, D. A. Ryndyk, and G. Cuniberti.
https://doi.org/10.1103/PhysRevB.92.035418

Grain boundaries are commonly observed in carbon nanostructures, but their influence on thermal and electric properties is still not completely understood. Using a combined approach of density functional tight-binding theory and nonequilibrium Green functions we investigate electron and phonon transport in carbon-based systems. In this work, quantum transport and thermoelectric properties are summarized for graphene sheets, graphene nanoribbons, and carbon nanotubes with a variety of grain boundary types in a wide temperature range. Motivated by previous findings that disorder scatters phonons more effectively than electrons, a significant improvement in the thermoelectric performance for polycrystalline systems is expected. As the effect is marginally sensitive to the grain boundary type, we demonstrate that grain boundaries are a viable tool to greatly enhance the figure of merit, paving the way for the design of new thermoelectric materials.

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Involved Scientists