Nanopowders of elements doped Bi2Te3thermoelectric 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 signifcant 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 coeffcient are not improved much by Ce doping,the thermal conductivity is supressed greatly.As a result the fgure of merit(ZT) of Ce0.2Bi1.8Te3is improved and reaches 1.29 at 398 K,which is higher than the Bi2Te3ingots made by the traditional zone-melting method Nanopowders of elements doped Bi2Te3 thermoelectric composite 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 signifcant effects on the morphologies of the synthesized nanopowders and thermoelectric properties. Amd the doping elements, Ce doping is a superiority dopant. Although the electrical conductivity and Seebeck coeffcient are not improved much by Ce doping, the thermal conductivity is supressed greatly. As a result of the fgure of merit (ZT) of Ce0.2Bi1.8Te3is improved and reached 1.29 at 398 K, which is higher than the Bi2Te3ingots made by the traditional zone-melting method