Na/Se掺杂p-型AgSbTe_2化合物热电性能研究

Enhanced Thermoelectric Performance in Na/Se Doped p-type AgSbTe_2 Compound

采用熔融-淬火-放电等离子烧结方法制备了两种不同掺杂方式的Na单掺和Na/Se共掺p型AgSbTe2多晶块体材料(Ⅰ:掺杂元素以过量形式添加AgNa0.01SbTe2,AgNa0.01SbTe2Se0.04;Ⅱ:掺杂元素以置换对应元素形式添加Ag0.99Na0.01SbTe2,Ag0.99Na0.01SbTe1.96Se0.04).研究了Na单掺、Na/Se共掺及不同掺杂方式对材料电、热输运性能的影响规律.通过比较不同掺杂方式样品的电、热传输性能确定了最佳的Na/Se掺杂方式:Na置换Ag,Se置换Te并结合适当的Se过量加入.由于Na掺杂对Seebeck系数的提高及Se掺杂对电导率和热导率的优化,Ag0.99Na0.01SbTe1.96Se0.04化合物ZT最大值在620 K达到1.4,较未掺杂AgSbTe2化合物提高约17%.

Two types of Na-doped and Na/Se co-doped polycrystalline,sintered samples of p-type AgSbTe2 thermo-electric compounds were prepared from high purity elements by a melt-quench technique followed by spark plasma sintering（Ⅰ： with excess Na or Na/Se,AgNa0.01SbTe2,AgNa0.01SbTe2Se0.04;Ⅱ ： replacing corresponding elements by Na or Na/Se,Ag0.99Na0.01SbTe2,Ag0.99Na0.01SbTe1.96Se0.04）.The impacts of Na-doping,Na/Se co-doping and doping form on electrical and thermal transport properties were investigated.Meanwhile,by comparing the thermoelectric performance of samples with different kinds of doping form,the optimal doping method is obtained.That is Na re-placing Ag,Se replacing Te with appropriate amount of excess Se.Due to the elevation of Seebeck coefficient by Na-doping and optimization of electrical and thermal conductivities by Se-doping,a maximum of ZT merit of 1.4 is achieved at 620 K for sample Ag0.99Na0.01SbTe1.96Se0.04,representing a 17% enhancement with respect to the undoped sample at the same temperature.