Enhanced thermoelectric figure of merit in polycrystalline carbon nanostructures

©https://www.dpg-physik.de/

DPG Frühjahrstagung der Sektion Kondensierte Materie (SKM) | event contribution
March 19, 2015 | Berlin, Germany

Grain boundaries are commonly observed in carbon nanostructures, but their influence on thermal and electronic properties are still not completely understood. Using a combined approach of density functional tight-binding theory and non-equilibrium 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 large 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. While the effect depends on the grain boundary type, we demonstrate that grain boundaries are a viable tool to greatly enhance the thermoelectric figure of merit, paving the way for the design of new thermoelectric materials.


Authors

Enhanced thermoelectric figure of merit in polycrystalline carbon nanostructures

©https://www.dpg-physik.de/

DPG Frühjahrstagung der Sektion Kondensierte Materie (SKM) | event contribution
March 19, 2015 | Berlin, Germany

Grain boundaries are commonly observed in carbon nanostructures, but their influence on thermal and electronic properties are still not completely understood. Using a combined approach of density functional tight-binding theory and non-equilibrium 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 large 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. While the effect depends on the grain boundary type, we demonstrate that grain boundaries are a viable tool to greatly enhance the thermoelectric figure of merit, paving the way for the design of new thermoelectric materials.


Authors