Thermal and Thermoelectrical Properties of Carbon Nanotube Beds

摘要

We measured the thermal conductivity, electrical conductivity and Seebeck coefficient of carbon nanotube (CNT) beds at variable CNT volume fractions and CNT doping levels. Unlike individual CNTs, which are known for having the highest thermal conductivity, the thermal conductivity of CNT beds is found as low as that of a thermal insulator. This unexpected low thermal conductivity can be caused by the phonon particle scattering at tube conjunctions and the interference effect of phonon wave transport between adjacent junctions. The electrical conductivity also decreases but not as much as the thermal conductivity does. The Seebeck coefficient is still on the same order of magnitude compared to that of individual nanotubes. These findings may suggest an effective way to enhance the figure of merit for thermoelectric applications.