Ga、K双掺杂P型Bi0.5Sb1.5Te3材料的制备及热电性能

Preparation and Thermoelectric Properties of Ga and K Dual Doped P-Type Bi0.5Sb1.5Te3

摘要:

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-xKxTe3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。

Abstract:

Ga and K dual doped Bi0.5Sb1.5Te3 thermoelectric materials were prepared by vacuum melting and hot pressing. XRD results indicate that all the characteristic peaks of the bulk Ga0.02Bi0.5Sb1.48-xKxTe3 can be indexed into Bi0.5Sb1.5Te3, but the diffraction peaks of the dual doped samples slightly lean to the left. Hot-pressed bulk materials exhibit the (00l) preferred orientation. SEM morphology shows that microstructure is dense and layered structure. The Seebeck coefficient of Bi0.5Sb1.5Te3 near the room temperature can be improved to some extent by Ga and K dual doping. The electrical conductivity of dual doped samples can be improved in different degrees, and electrical conductivity of Ga0.02Bi0.5Sb1.42K0.06Te3 samples is improved obviously. In the whole measured temperature range of 300~500 K, the thermal conductivity of the dual doped samples is higher than that of Bi0.5Sb1.5Te3. ZT values of the dual doped samples are improved at near 300 K, and the ZT value of Ga0.02Bi0.5Sb1.42K0.06Te3 sample reaches 1.5 at 300 K.