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

Influence of Ag_2Te Doping on the Thermoelectric Properties of p-type Bi_(0.5)Sb_(1.5)Te_3 Bulk Alloys

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%.

（Ag2Te）x（Bi0.5Sb1.5Te3）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（Bi0.5Sb1.5Te3）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（Bi0.5Sb1.5Te3）0.95.Compared with the one without doping,the ZT value is increased by almost 20%.