Strong anharmonicity induced low lattice thermal conductivity and high thermoelectric performance in (CuInTe2)1−<i>x</i>(AgSbTe2)<i>x</i> system
Qihong Xiong, Yanci Yan, Nanhai Li, Bin Zhang, Sikang Zheng, Yajie Feng, Guiwen Wang, Guiwen Wang, Huijun Liao, Zhengyong Huang, Jian Li, Guoyu Wang, Guoyu Wang, Xu Lu, Xiaoyuan Zhou
Abstract
The suppression of lattice thermal conductivity of thermoelectric CuInTe2 was often realized by complex micrometer-structure control. Herein, we demonstrate that simple alloying AgSbTe2 in CuInTe2 is capable of strongly strengthening lattice anharmonicity, which gives rise to an extremely low lattice thermal conductivity of ∼ 0.62 W m−1 K−1 at 823 K for (CuInTe2)0.95(AgSbTe2)0.05. In addition, the intentionally introduced copper vacancies can effectively increase the carrier concentration and dramatically improve the electrical performance of (CuInTe2)0.95(AgSbTe2)0.05. As a result, the sample with nominal composition of (Cu0.95InTe2)0.95(AgSbTe2)0.05 reaches a maximum zT value of ∼ 1.3 at 823 K. This study provides some insight into designing thermoelectric compounds in the diamond-like semiconductor family by inducing strong anharmonicity through a small amount of alloying.