铅掺杂铋铜硒氧的微波合成与热电性能研究

Microwave synthesis and thermoelectric properties of Pb-doped BiCuSeO oxyselenides

采用微波加热合成结合放电等离子烧结制备出Bi1-xPbxCuSeO(x=0,0.2,0.3)热电块体样品,并对它们的物相组成、微观结构、电输运机制和热输运机制进行了研究。研究结果表明,采用微波加热成功合成出高纯度Bi1-xPbxCuSeO,随后采用放电等离子体烧结获得了元素分布均匀、相对致密度99%的块体样品;Bi位铅的掺入显著降低了样品电阻率,导电性随铅浓度的增加而提高,Bi0.7Pb0.3CuSeO的电阻率仅为4.6~9.3μΩ·m;塞贝克系数有所降低,但功率因子大幅提高至约800μWm^-2·m^-1;Pb掺杂降低了样品晶格热导率,但由于导电性的提高导致电子热导率增高,使得掺杂样品总热导率略高于未掺杂样品;由于综合电性能的显著提高,Bi0.2Pb0.8CuSeO在773 K获得最大热电优值0.54,相比未掺杂样品提升25%。

A series of oxyselenides thermoelectric bulks Bi1-xPbxCuSeO(X=0,0.2,0.3)were successful fabricated via microwave heating synthesis combined with spark plasma sintering for the first time,and their phase composition,microstructure and thermoelectric transport properties were investigated.The experimental results show that high purity Bi1-xPbxCuSeO were successfully synthesized by microwave heating,and the corresponding bulks with uniform element distribution and relative density of 99%were obtained by using spark plasma sintering.Partial substitution of Pb to Bi resulting in significantly reduced the resistivity.The conductivity increased with the increasing Pb concentration.The Seebeck coefficient decreased with the increasing Pb concentration,whereas the power factor increased to about 800μW/(m·K^2).Pb-doping reduced the lattice thermal conductivity to some degree,however the total thermal conductivity were slightly higher than that of the undoped sample due to the increase of electron thermal conductivity caused by the improvement of electrical conductivity.Due to the significant improvement of comprehensive electrical performance,the Bi0.8Pb0.2CuSeO obtained highest thermoelectric figure of merit(ZT)of 0.54 at 773 K,which was 25%higher than that of the undoped sample.