Contrasting the Role of Mg and Ba Doping on the Microstructure and Thermoelectric Properties of p-Type AgSbSe2

详细信息    查看全文

• 作者：Zihang Liu ; Jing Shuai ; Huiyuan Geng ; Jun Mao ; Yan Feng ; Xu Zhao ; Xianfu Meng ; Ran He ; Wei Cai ; Jiehe Sui
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：October 21, 2015
• 年：2015
• 卷：7
• 期：41
• 页码：23047-23055
• 全文大小：574K
• ISSN：1944-8252

文摘

Microstructure has a critical influence on the mechanical and functional properties. For thermoelectric materials, deep understanding of the relationship of microstructure and thermoelectric properties will enable the rational optimization of the ZT value and efficiency. Herein, taking AgSbSe₂ as an example, we first report a different role of alkaline-earth metal ions (Mg²⁺ and Ba²⁺) doping in the microstructure and thermoelectric properties of p-type AgSbSe₂. For Mg doping, it monotonously increases the carrier concentration and then reduces the electrical resistivity, leading to a substantially enhanced power factor in comparison to those of other dopant elements (Bi³⁺, Pb²⁺, Zn²⁺, Na⁺, and Cd²⁺) in the AgSbSe₂ system. Meanwhile, the lattice thermal conductivity is gradually suppressed by point defects scattering. In contrast, the electrical resistivity first decreases and then slightly rises with the increased Ba-doping concentrations due to the presence of BaSe₃ nanoprecipitates, exhibiting a different variation tendency compared with the corresponding Mg-doped samples. More significantly, the total thermal conductivity is obviously reduced with the increased Ba-doping concentrations partially because of the strong scattering of medium and long wavelength phonons via the nanoprecipitates, consistent with the theoretical calculation and analysis. Collectively, ZT value 鈭? at 673 K and calculated leg efficiency 鈭?.5% with T_c = 300 K and T_h = 673 K are obtained for both AgSb_0.98Mg_0.02Se₂ and AgSb_0.98Ba_0.02Se₂ samples.