Waqar Mahmood

Pronounced effect of ZnTe nanoinclusions on thermoelectric properties of Cu 2−x Se chalcogenides

Metal chalcogenides especially Cu2−xSe has gained much attention in thermoelectric community due to its complex crystal structure and superionic behavior. Here, we report a facile method to improve the thermoelectric efficiency by introducing ZnTe nanoinclusions into the matrix of Cu2−xSe. As a result, a substantial improvement of 32% in electrical conductivity of Cu2−xSe-ZnTe composite is observed. The increase in electrical conductivity is at the expense of Seebeck coefficient, which slightly decreases the power factor of the composite samples than that of pure Cu2−xSe. Furthermore, the introduction of secondary phase facilitates in declining the total thermal conductivity of Cu2−xSe-ZnTe composite up to 34% by suppressing the lattice thermal contributions. Thus, the moderate power factor and lower thermal conductivity values result in an improved figure of merit (zT) value of ∼0.40 in mid-range temperature (750 K) for Cu2−xSe-ZnTe composite with 10 wt.% of ZnTe, which is about 40% higher than that of its pure counterpart. Hence, it is believed that the incorporation of ZnTe nanoinclusions in the matrix of Cu2−xSe may be an important route to improve the thermoelectric properties of Cu2−xSe based compounds.摘要由于具有复杂的晶体结构和超离子导体行为, 金属硫属化合物特别是Cu2−xSe在热电领域得到了广泛的关注. 本文报道了一种简单易行的提高热电效率的方法:在基体材料Cu2−xSe中添加纳米ZnTe插层, 用来提高Cu2−xSe材料的热电性能. 实验结果表明, Cu2−xSe-ZnTe复合材料的电导率提高了32%, 电导率的增加牺牲了塞贝克系数, 导致复合材料的功率因子稍微低于纯Cu2−xSe基体材料; 第二相的引入抑制了晶格热扩散, 使得Cu2−xSe-ZnTe复合材料的热导率降低了34%. 由此可知, 适中的功率因子和较低的热导率致使含有10 wt.%ZnTe的Cu2−xSe-ZnTe复合材料在中温条件(750 K)下的zT值提高至0.40, 相比于纯Cu2−xSe基体材料该数值提高了40%. 因此, 向Cu2−xSe材料中添加纳米ZnTe插层, 是提高Cu2−xSe基材料热电性能的一个有效途径.

Pronounced effect of ZnTe nanoinclusions on thermoelectric properties of Cu2−xx

Metal chalcogenides especially Cu2−xSe has gained much attention in thermoelectric community due to its complex crystal structure and superionic behavior. Here, we report a facile method to improve the thermoelectric efficiency by introducing ZnTe nanoinclusions into the matrix of Cu2−xSe. As a result, a substantial improvement of 32% in electrical conductivity of Cu2−xSe-ZnTe composite is observed. The increase in electrical conductivity is at the expense of Seebeck coefficient, which slightly decreases the power factor of the composite samples than that of pure Cu2−xSe. Furthermore, the introduction of secondary phase facilitates in declining the total thermal conductivity of Cu2−xSe-ZnTe composite up to 34% by suppressing the lattice thermal contributions. Thus, the moderate power factor and lower thermal conductivity values result in an improved figure of merit (zT) value of ∼0.40 in mid-range temperature (750 K) for Cu2−xSe-ZnTe composite with 10 wt.% of ZnTe, which is about 40% higher than that of its pure counterpart. Hence, it is believed that the incorporation of ZnTe nanoinclusions in the matrix of Cu2−xSe may be an important route to improve the thermoelectric properties of Cu2−xSe based compounds.摘要由于具有复杂的晶体结构和超离子导体行为, 金属硫属化合物特别是Cu2−xSe在热电领域得到了广泛的关注. 本文报道了一种简单易行的提高热电效率的方法:在基体材料Cu2−xSe中添加纳米ZnTe插层, 用来提高Cu2−xSe材料的热电性能. 实验结果表明, Cu2−xSe-ZnTe复合材料的电导率提高了32%, 电导率的增加牺牲了塞贝克系数, 导致复合材料的功率因子稍微低于纯Cu2−xSe基体材料; 第二相的引入抑制了晶格热扩散, 使得Cu2−xSe-ZnTe复合材料的热导率降低了34%. 由此可知, 适中的功率因子和较低的热导率致使含有10 wt.%ZnTe的Cu2−xSe-ZnTe复合材料在中温条件(750 K)下的zT值提高至0.40, 相比于纯Cu2−xSe基体材料该数值提高了40%. 因此, 向Cu2−xSe材料中添加纳米ZnTe插层, 是提高Cu2−xSe基材料热电性能的一个有效途径.