Effect of Lone-pair Electron on Thermoelectric Transmission Performance of Tellurium
LI Rong1, CHEN Shaoping1, FAN Wenhao2, CHEN Yanzuo1, XU Libin1, WANG Wenxian1, WU Yucheng1
1 College of Material Science and Engineering, Taiyuan University of Technology, Taiyuan 030024; 2 College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024
Abstract: Tellurium is an excellent thermoelectric (TE) material, has very high Seebeck coefficient, mobility and extra low thermal conductivity. In this paper, polycrystalline samples of pure Te and SbxTe1-x were prepared using melt-alloying and hot-pressing techniques, and Te crystals were prepared by vertical Bridgman-Stockbarge method. Then thermoelectric properties of the obtained crystals were studied. The results show that Te has a high Seebeck coefficient and conductivity, and Sb doping effectively improves the thermoelectric properties of Te, the conductivity of Te crystals prepared by vertical Bridgman-Stockbarge method shows obvious anisotropy. These results are mainly attributed to degenerate band in valance band, step-like DOS distribution near Fermi level and large phonon scattering phase. This effect can be attributed to the lone-pair electrons in Te lattice, which enable these characters benefiting TE transport properties. This study illustrates the lone-pair electrons of Te are origins of these properties by decoupling σ, α and κ, which also offer a new character to look for good TE materials.
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2018, Vol. 32 
