Effects of Ce, Y, and Sm doping on the thermoelectric properties of Bi2Te3 alloy

Nanopowders of elements doped Bi2Te3 thermoelectric alloy R0.2Bi1.8Te3 (R=Ce, Y and Sm) were synthesized by the hydrothermal method. The nanopowders were hot-pressed into pellets and their thermoelectric properties were investigated. The results show that Ce, Y, and Sm doping has significant effects on the morphologies of the synthesized nanopowders and thermoelectric properties. Among the doping elements, Ce doping is a superiority dopant. Although the electrical conductivity and Seebeck coefficient are not improved much by Ce doping, the thermal conductivity is supressed greatly. As a result the figure of merit (ZT) of Ce0.2Bi1.8Te3 is improved and reaches 1.29 at 398 K, which is higher than the Bi2Te3 ingots made by the traditional zone-melting method