Ga、K双掺杂对N型Bi_2Te_(2.7)Se_(0.3)材料热电性能的影响

Effects of Ga and K Dual Doping on Thermoelectric Properties of N-type Bi_2Te_(2.7)Se_(0.3)

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。

N-type Bi2Te2.7Se0.3 thermoelectric materials with Ga and K dual doping were synthesized by vacuum melting and hot pressing. XRD results indicate that Ga and K elements have been completely dissolved into the crystal structure of Bi2Te2.7Se0.3. The single-phase solid solution alloy has been formed. SEM results show that the bulk samples are compact with the laminated structure. Ga and K dual doping increases the Seebeck coefficient of Bi2Te2.7Se0.3 through Ga and K partial substitution of Bi in the most range of 300-500 K, while the electrical conductivity of the dual doped samples is improved. The thermal conductivity of the dual doped samples is higher than that of Bi2Te2.7Se0.3. The maximum ZT value reaches 1.05 at 500 K for Ga0.02Bi1.94K0.04Te3Se0.3 sample.