Enhanced Thermoelectric Properties of Cu₂SnSe₃ by (Ag,In)-Co-Doping

详细信息    查看全文

• 作者：Yuyang Li ; Guanghua Liu ; Tengfei Cao ; LiMin Liu ; Jiangtao Li ; Kexin Chen ; Laifeng Li ; Yemao Han and Min Zhou
• 刊名：Advanced Functional Materials
• 出版年：2016
• 出版时间：September 6, 2016
• 年：2016
• 卷：26
• 期：33
• 页码：6025-6032
• 全文大小：1963K
• ISSN：1616-3028

文摘

Dense bulk samples of (Ag,In)-co-doped Cu₂SnSe₃ have been prepared by a fast and one-step method of combustion synthesis, and their thermoelectric properties have been investigated from 323 to 823 K. The experimental results show that Ag-doping at Cu site remarkably enhances the Seebeck coefficient, reduces both electrical and thermal conductivities, and finally increases the figure of merit (ZT) value. The ZT of the Cu_1.85Ag_0.15SnSe₃ sample reaches 0.80 at 773 K, which is improved by about 70% compared with the unadulterated sample (ZT = 0.46 at 773 K). First principle calculation indicates that Ag-doping changes the electronic structure of Cu₂SnSe₃ and results in larger effective mass of carriers, thus enhancing the Seebeck coefficient and reducing the electrical conductivity. The low electrical conductivity caused by Ag-doping can be repaired by accompanying In-doping at Sn site, and by (Ag,In)-co-doping the thermoelectric properties are further promoted. The (Ag,In)-co-doped sample of Cu_1.85Ag_0.15Sn_0.9In_0.1Se₃ shows the maximum ZT of 1.42 at 823 K, which is likely the best result for Cu₂SnSe₃-based materials up to now. This work indicates that co-doping may provide an effective solution to optimize the conflicting material properties for increasing ZT.