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采用真空熔炼和热压方法制备了Ga和K双掺杂Bi0.5Sb1.5Te3热电材料。XRD结果表明,Ga0.02Bi0.5Sb1.48-x Kx Te3块体材料的XRD图谱与Bi0.5Sb1.5Te3的XRD图谱对应一致,但双掺杂样品的衍射峰略微向左偏移。热压块体材料中存在明显的(00l)晶面择优取向。SEM形貌表明材料组织致密且有层状结构特征。Ga和K双掺杂可使Bi0.5Sb1.5Te3在室温附近的Seebeck系数有一定的提高,而双掺杂样品的电导率均得到了不同程度的提高,其中Ga0.02Bi0.5Sb1.42K0.06Te3样品的电导率得到较明显的改善。在300~500 K测量温度范围内,所有双掺杂样品的热导率高于Bi0.5Sb1.5Te3的热导率,在300 K附近双掺杂样品的ZT值得到提高,其中Ga0.02Bi0.5Sb1.42K0.06Te3样品在300 K时ZT值达到1.5。
Ga and K double-doped Bi0.5Sb1.5Te3 thermoelectric materials were prepared by vacuum melting and hot pressing. The XRD results show that the XRD pattern of Ga0.02Bi0.5Sb1.48-xKxTe3 bulk material is consistent with the XRD pattern of Bi0.5Sb1.5Te3, but the diffraction peak of the double-doped sample is slightly shifted to the left. There are obvious preferential orientation of (001) plane in the hot-pressed bulk material. The SEM morphology shows that the material has a dense and layered structure. Ga and K double doping can Bi0.5Sb1.5Te3 Seebeck coefficient near room temperature have a certain increase, while the conductivity of double doped samples have been improved to varying degrees, in which Ga0.02Bi0Sb1.42K0.06Te3 The conductivity of the sample was significantly improved. The thermal conductivities of all the doping samples are higher than that of Bi0.5Sb1.5Te3 in the temperature range of 300 ~ 500 K. The ZT value of the doping samples near 300 K is improved, in which Ga0.02Bi0. The ZS value of the 5Sb1.42K0.06Te3 sample reached 1.5 at 300 K.