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采用真空熔炼及热压方法制备了Ga和K双掺杂N型Bi2Te2.7Se0.3热电材料。XRD分析结果表明,Ga和K已经完全固溶到Bi2Te2.7Se0.3晶体结构中,形成了单相固溶体合金。SEM分析表明,材料组织致密且有层状结构特征。通过Ga和K部分替代Bi,在300~500 K的大部分温度范围内,Ga和K双掺杂对提高Bi2Te2.7Se0.3的Seebeck系数产生了积极的作用,同时双掺杂样品的电导率也得到明显的提高。Ga和K双掺杂样品的热导率都大于未掺杂的Bi2Te2.7Se0.3,Ga0.02Bi1.94K0.04Te2.7Se0.3合金在500 K获得ZT最大值为1.05。
Ga and K double-doped N-type Bi2Te2.7Se0.3 thermoelectric materials were prepared by vacuum melting and hot pressing. The results of XRD analysis show that Ga and K have been completely dissolved into the crystal structure of Bi2Te2.7Se0.3, forming single-phase solid solution alloy. SEM analysis shows that the material has dense and layered structure. By Ga and K partial replacement of Bi, Ga and K double doping in the most temperature range of 300 ~ 500 K have a positive effect on improving the Seebeck coefficient of Bi2Te2.7Se0.3, while the conductivity of double doping samples Have also been significantly improved. The thermal conductivities of both Ga and K doping samples are larger than that of undoped Bi2Te2.7Se0.3. The maximum ZT value of Ga0.02Bi1.94K0.04Te2.7Se0.3 alloy obtained at 500 K is 1.05.