Effects of Pd and Pt double doping on thermoelectric properties of CoSb₃

Abstract

Double doping of Pd and Pt in the skutterudite CoSb₃ as donor impurities has been studied to produce a prominent effect on improving the thermoelectric figure of merit values. The double doping was found to have a beneficial effect on increasing the carrier concentration, causing a large increase of electrical conductivity as compared with that for the single doping of Pd or Pt. The electrical conductivity of about 2000 S/cm was obtained at room temperature for hot-pressed samples with Pd and Pt of 5 atomic per cent (Co_0.9Pd_0.05Pt_0.05Sb₃). In addition, the double doping significantly affected the lattice thermal conductivity, resulting in a large reduction of thermal conductivity to 0.05W/cmK. As a result, the dimensionless thermoelectric figure of merit reached about 0.85 at 800K.