Nanostructures and enhanced thermoelectric properties in Ce-filled skutterudite bulk materials

The nanostructures induced by uniaxial compression in Ce0.29Fe1.40Co2.60Sb11.24 bulk thermoelectric material is reported. High-resolution transmission electron microscope images reveal that the nanostructures consist of Ce0.31Fe1.38Co2.62Sb11.56 crystals and Fe0.34Co0.66Sb1.99 minicrystal/noncrystal with grain sizes about 5-20 nm. It is shown that the Seebeck coefficient is increased by 21%, the phonon thermal conductivity is reduced by 19%, while the electrical conductivity rises slightly at 300 K. This leads to a surprising increase in the power factor by 51%. The significant increase of Seebeck coefficient and the remarkable reduction of phonon thermal conductivity are believed to be due to quantum effect and size effect of the nanostructures, respectively. (c) 2006 American Institute of Physics.