采用真空封管熔炼缓冷和热压法制备Pb9.6SbmTe3Se7合金样品（m=0.15,0.2,0.25,0.267,0.3,0.35,0.4）,研究Sb的掺杂量对热电性能的影响。结果显示,除m=0.4的样品由于Sb含量过多呈金属特性外,随着Sb含量的增加,载流子迁移率降低,电导率减小,热导率呈减小趋势,且都明显低于PbTe的热导率。HRTEM显示样品中广泛存在着不同形貌的纳米微区,增加了声子散射,有效降低热导,提高热电优值。其中Pb9.6Sb0.3Te3Se7样品在677K时ZT达到的1.14,与目前可复现的n型掺杂PbTe基材料的最大ZT值相比,增长近50%。
Pb9.6SbmTe3Se7 alloys(m=0.15,0.2,0.25,0.267,0.3,0.35,0.4) have been synthesized by slow cooling followed smelting in evacuated tubes and powder hot pressing,and the effect of Sb doping on the thermoelectric performance was investigated.As the Sb content increases,except for the alloy of m=0.4,carrier mobility decreases,electrical conductivity decreases,and thermal conductivity shows a decreasing trend,significantly lower than the thermal conductivity of PbTe.HRTEM images suggest the Pb9.6Sb0.3Te3Se7 phases are inhomogeneous with widely distributed nanosized islands with different shapes,which are favorable to the strong suppression of the lattice thermal conductivity.Finally,the thermoelectric properties of the materials have been improved by Sb doping.It is noteworthy that Pb9.6Sb0.3Te3Se7 exhibits a high thermoelectric figure of merit,with the highest ZT ~1.14 at 673 K,which is about 50% higher than that of the state-of-the-art n-type PbTe reported previously.
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