文章基本信息

标题：Enhanced Thermoelectric Performance of Cu2CdSnSe4 by Mn Doping: Experimental and First Principles Studies
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作者：F. S. Liu ; J. X. Zheng ; M. J. Huang 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2015
卷号：4
期号：1
DOI：10.1038/srep05774
语种：English
出版社：Springer Nature
摘要：Serials of Mn doping by substituting Cd sites on Cu₂CdSnSe₄ are prepared by the melting method and the spark plasma sintering (SPS) technique to form Cu₂Cd_{1− x}Mn _x SnSe₄. Our experimental and theoretical studies show that the moderate Mn doping by substituting Cd sites is an effective method to improve the thermoelectric performance of Cu₂CdSnSe₄. The electrical resistivity is decreased by about a factor of 4 at 723 K after replacing Cd with Mn, but the seebeck coefficient decreases only slightly from 356 to 289 μV/K, resulting in the significant increase of the power factor. Although the thermal conductivity increases with the doping content of Mn, the figure of merit ( ZT ) is still increased from 0.06 ( x = 0) to 0.16 ( x = 0.10) at 723 K, by a factor of 2.6. To explore the mechanisms behind the experimental results, we have performed an ab initio study on the Mn doping effect and find that the Fermi level of Cu₂CdSnSe₄ is shifted downward to the valence band, thus improving the hole concentration and enhancing the electrical conductivity at the low level doping content. Optimizing the synthesis process and scaling Cu₂Cd_1−xMn_xSnSe₄ to nanoparticles may further improve the ZT value significantly by improving the electrical conductivity and enhancing the phonon scattering to decrease the thermal conductivity.