Enhancement of thermoelectric properties of In-filled and Te-doped CoSb3 synthesized by high pressure technique

Bulk In-filled and Te-doped CoSb3 materials have been synthesized by high pressure and high temperature (HPHT) method directly. XRD and SEM images showed that In0.3Co4Sb11.5Te0.5 with fine grain sizes could be quickly synthesized by HPHT, using only half an hour. HRTEM observation revealed the different kinds of defects in the high pressure synthesized samples. The different synthesis pressures dramatically reduced the lattice thermal conductivity due to enhance the multiple microstructures and defects phonon scattering effects, and simultaneously enhanced the Seebeck coefficient. Finally, the figure of merit (ZT) values of samples increased with the increase of synthesis pressures.