Beneficial effect of Se substitution on thermoelectric properties of Co4Sb11.9-xTexSe0.1 skutterudites
Skutterudite-based compounds, Co4Sb12-x-yTexSey (x=0.4, 0.5, 0.6 and y=0.0, 0.1), are synthesized by the solid state reaction and the spark plasma sintering methods, and their structure and the thermoelectric properties have been investigated systematically. It is found that Se doping results in decrease of the lattice parameter and refinement of the particle size compared with those of Se-free samples. The Se-doped samples do not yield a certain increase in the power factor, but show a significant depression in the lattice thermal conductivity. The highest dimensionless figure of merit ZT=1.09 is achieved at 800 K for the Co4Sb11.3Te0.6Se0.1 compound, which is improved by 15% compared with that of Te alone doped Co4Sb11.4Te0.6 compound at the corresponding temperature.