Low-temperature soft-chemical synthesis and thermoelectric properties of barium-filled p-type skutterudite nanocrystals

Bulk skutterudites, such as cobalt triantimonide (CoSb3) are promising inorganic materials for thermoelectric power generation at high temperatures. Generally, bulk CoSb3 is synthesized by high temperature solid state reactions. Herein, we demonstrate the low temperature solution phase synthesis of p-type nanocrystalline CoSb3 and Ba-filled CoSb3. Increase in the temperature dependent Seebeck coefficient with simultaneous increase in temperature dependent electrical conductivity has been observed in the present nanocrystalline samples, which is unusual in the case of bulk CoSb3. Efficient phonon scattering by nanoscale grain boundaries and the additional phonon damping due to the rattling of Ba in the void of nanocrystalline CoSb3 give rise to low thermal conductivity, which results in improved thermoelectric performance in nanocrystalline p-type Ba0.048CoSb3.