Phase transition and high temperature thermoelectric properties of copper selenide Cu_(2-x) Se (0 ≤ x ≤ 0.25)  

作　　者：肖星星 谢文杰 唐新峰 张清杰 

机构地区：[1]State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,Wuhan University of Technology

出　　处：《Chinese Physics B》2011年第8期340-347,共8页中国物理B（英文版）

基　　金：Project supported by the National Basic Research Program of China (Grant No. 2007CB607501);the National Natural Science Foundation of China (Grant Nos. 50731006 and 50672118) along with 111 Project (Grant No. B07040)

摘　　要：With good electrical properties and an inherently complex crystal structure, Cu2-xSe is a potential ＂phonon glass electron crystal＂ thermoelectric material that has previously not attracted much interest. In this study, Cu2-xSe （0 ≤ x ≤0.25） compounds were synthesized by a melting-quenching method, and then sintered by spark plasma sintering to obtain bulk material. The effect of Cu content on the phase transition and thermoelectric properties of Cu2-xSe were investigated in the temperature range of 300 K-750 K. The results of X-ray diffraction at room temperature show that Cu2-xSe compounds possess a cubic structure with a space group of Fm3m （#225） when 0.15 〈 x ≤ 0.25, whereas they adopt a composite of monoclinic and cubic phases when 0 ≤x ≤ 0.15. The thermoelectric property measurements show that with increasing Cu content, the electrical conductivity decreases, the Seebeck coefficient increases and the thermal conductivity decreases. Due to the relatively good power factor and low thermal conductivity, the nearly stoichiometric Cu2Se compound achieves the highest ZT of 0.38 at 750 K. It is expected that the thermoelectric performance can be further optimized by doping appropriate elements and/or via a nanostructuring approach.With good electrical properties and an inherently complex crystal structure, Cu2-xSe is a potential ＂phonon glass electron crystal＂ thermoelectric material that has previously not attracted much interest. In this study, Cu2-xSe （0 ≤ x ≤0.25） compounds were synthesized by a melting-quenching method, and then sintered by spark plasma sintering to obtain bulk material. The effect of Cu content on the phase transition and thermoelectric properties of Cu2-xSe were investigated in the temperature range of 300 K-750 K. The results of X-ray diffraction at room temperature show that Cu2-xSe compounds possess a cubic structure with a space group of Fm3m （#225） when 0.15 〈 x ≤ 0.25, whereas they adopt a composite of monoclinic and cubic phases when 0 ≤x ≤ 0.15. The thermoelectric property measurements show that with increasing Cu content, the electrical conductivity decreases, the Seebeck coefficient increases and the thermal conductivity decreases. Due to the relatively good power factor and low thermal conductivity, the nearly stoichiometric Cu2Se compound achieves the highest ZT of 0.38 at 750 K. It is expected that the thermoelectric performance can be further optimized by doping appropriate elements and/or via a nanostructuring approach.

关 键 词：copper selenide phase transition thermoelectric properties 

分 类 号：O611.3[理学—无机化学]