  p-type Ce1.05Fe4Sb12.04 filled skutterudites with much improved
thermoelectric properties have been synthesized by rapidly converting nearly
amorphous ribbons into crystalline pellets under pressure. It is found that
this process greatly suppresses grain growth and second phase
formation/segregation, and hence results in the samples consisting of
nano-sized grains with strongly-coupled grain boundaries, as observed by
transmission electron microscopy. The room temperature carrier mobility in
these samples is significantly higher (nearly double) than those in the samples
of the same starting composition made by the conventional solid-state reaction.
Nanostructure reduces the lattice thermal conductivity, while cleaner grain
boundaries permit higher electron conduction.
