Ag_2Te掺杂对p型Bi_(0.5)Sb_(1.5)Te_3块状合金热电性能的影响

采用真空熔炼、机械球磨及放电等离子烧结技术(SPS)制备得到了(Ag2Te)x(Bi0.5Sb1.5Te3)1-x(x=0,0.025,0.05,0.1)系列样品,性能测试表明,Ag2Te的掺入可以显著改变材料的热电性能变化趋势,掺杂样品在温度为450~550K范围内具有较未掺杂样品更优的热电性能.适当量的Ag2Te掺入能够有效地提高材料的声子散射,降低材料的热导率.在测试温度范围内,(Ag2Te)0.05(Bi0.5Sb1.5Te3)0.95具有最低的晶格热导,室温至575K范围内保持在0.2~0.3W/(m·K)之间,在575K时,(Ag2Te)0.05(Bi0.5Sb1.5Te3)0.95试样具有最大热电优值ZT=0.84,相较于未掺杂样品提高了约20%.

Influence of Ag2Te Doping on the Thermoelectric Properties of p-type Bi0.5Sb1.5Te3 Bulk Alloys

(Ag₂Te)_x(Bi_0.5Sb_1.5Te₃)_1-x(x=0, 0.025, 0.05, 0.1) alloys were synthesized by “Melting-Ball Milling-Spark Plasma Sintering” method. Transport properties measurements indicate that the Ag₂Te-doping can affect the temperature dependence of thermoelectric properties of the samples significantly. Samples with Ag₂Te-doping have better thermoelectric performances in the temperature range from 450 K to 550 K. Appropriate amount of Ag₂Te can enhance the phonon scattering of the alloys effectively, which lead to the lower thermal conductivities for these samples. Over the entire temperature range, sample (Ag₂Te)_0.05(Bi_0.5Sb_1.5Te₃)_0.95 exhibits the lowest lattice thermal conductivities, ranging within 0.2-0.3 W/(m·K) from room temperature to 575 K. The maximum ZT value of 0.84  is obtained at 575 K for the sample (Ag₂Te)_0.05(Bi_0.5Sb_1.5Te₃)_0.95. Compared with the one without doping, the ZT value is increased by almost 20%.