Effect of Nb doping on microstructures and thermoelectric properties of SrTiO3 ceramics

• 来源期刊: 中国物理B（英文版）
• 关键词: thermoelectric materials SrTiO3 Nb-doped sintering temperature
• 年，卷（期）: 2018,（4）
• 页码范围: 90-95
• 页数: 6页
• 语种: 英文
• DOI: 10.1088/1674-1056/27/4/047205

摘要

Nb-doped SrTiO3 thermoelectric ceramics with different niobium concentrations, sintering temperatures and Sr-site vacancies are successfully prepared by high energy ball milling combined with carbon burial sintering. For fully under-standing the effect of niobium doping on SrTiO3, thermoelectric transport properties are systematically investigated in a temperature range from 300 K to 1100 K. The carrier mobility can be significantly enhanced, and the electrical conductivity is quadrupled, when the sintering temperature rises from 1673 K to 1773 K (beyond the eutectic temperature (1713 K) of SrTiO3–TiO2). The lattice vibration can be suppressed by the lattice distortion introduced by the doped niobium atoms. However, Sr-site vacancies compensate for the lattice distortion and increase the lattice thermal conductivity more or less. Finally, we achieve a maximum value of figure-of-merit zT of 0.21 at 1100 K for SrTi0.9Nb0.1O3 ceramic sintered at 1773 K.