Synthesis and thermoelectric properties of nanosize CoSb$_{3}$ skutterudite by solvothermal route

Skutterudite CoSb$_{3}$ material has remarkable thermoelectric property and great potential applications for thermoelectric power generation and solid state cooling. In this work, we report the synthesis of the skutterudite CoSb$_{3}$ nanoparticles by solvothermal method with or without surfactants. Pure cubic phase of CoSb$_{3}$ has been synthesized with or without the surfactants; however, the size and shape of the CoSb$_{3}$ nanoparticles are affected by the surfactants. The small particles have an optical band gap of around 3.44 eV and a broad photoluminescence emission band with maximum at 409 nm. Thermoelectric measurements were performed on the nanosize CoSb$_{3}$ materials. A maximum power factor of 1.3$\times $10$^{-4}$Wm$^{-1}$K$^{-2}$, low thermal conductivity of 1.5 Wm$^{-1}$K$^{-1}$ and thermoelectric figure of merit (ZT) of 0.06 was obtained at 720 K. The skutterudite CoSb$_{3}$ nanostructures may be used to develop high efficiency thermoelectric devices.