摘要
采用真空熔炼及热压烧结技术制备了Na和Al双掺杂P型Bi0．5Sb1．5Te3热电材料。利用X射线衍射（XRD）、扫描电子显微镜（SEM）对样品的物相结构和表面形貌进行了表征。XRD分析结果表明，Na0．04Bi0．5Sb1．46-xAlxTe3块体材料的XRD图谱与块体材料Bi0．5Sb1．5Te3的图谱完全对应，所有块体材料的衍射峰均与衍射卡JCPDS49-1713对应，这表明Na和Al元素已经完全固溶到Bi0．5sbl．5Te3晶体结构中，形成了单相固溶体合金。SEM形貌表明材料组织致密且有层状结构特征。Na和Al双掺杂提高了Bi0．5Sb1．5Te3在室温附近的Seebeck系数。在Na掺杂量为0．04时，同时Al掺杂量由x=0．04增加至0．12，电导率逐渐降低，在实验掺杂浓度范围内，Na和Al双掺杂会使P型Bi0．5Sb1．5Te3材料的电导率受到较大的损失。在300-500K时，通过Na和Al部分替代Sb，Nao．04Bi0．5Sb1．42Al0．04Te3和Na0．04Bi0．5Sb1．38Al0．08Te3样品的热导率均有不同程度地减小，在300K时双掺杂样品Na0．04Bi0．5Sb1．42A10．04Te3的最大ZT值达到1．45。
Na and AI dual doped P-type Bi0.5Sb1.5Te3 thermoelectric materials were synthesized by vacuum melting and hot pressing method. Phase structure and surface morphology were analyzed by X-ray diffraction （ XRD）, scanning electron microscope （ SEM ）. XRD results indicated that all the characteristic peaks of the bulk Na0.04Bi0.8Sb1.4-xAlxTe3 could be indexed into bulk Bi0.5Sb1.5Te3. All diffraction peaks of the bulk materials were consistent with the diffraction cards JCPDS 49-1713. This indicated that Na and AI ele- ments were completely dissolved into the crystal structure of Bi0.5Sb1.5Te3. The single-phase solid solution alloy was formed. SEM re- suits showed that the bulk samples were compact with the laminated structure. Na and A1 dual doping improved the Seebeck coefficient of Bi0.5Sb1.5Te3 near the room temperature. While the concentration of Na was 0.04, the concentrations of Al increased from x =0.04 to 0. 12, the electrical conductivity decreased gradually in the experimental concentration range. Na and AI dual doping could make the electrical conductivity of P-type Bi0.5Sb1.5Te3 material a great loss. The thermal conductivity of Na0.04 Bi0.5 SbL42 Al0.04 Te3 and Na0.04 Bi0.5Sb1.38Al0.08Te3 samples were decreased through Na and AI partial substitution of Sb in 300 - 500 K. The maximum ZT value reached 1.45 at 300 K for Na0.04Bi0.5SbL42Al0.04Te3 sample.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2013年第5期757-761,共5页
Chinese Journal of Rare Metals
基金
国家自然科学基金项目(51161009)
江西省教育厅科技项目(GJJ13722)资助
关键词
双掺杂
热压
微结构
热电性能
： dual doping
hot pressing
microstructure
thermoelectric properties
