Realizing High Thermoelectric Performance in ZnCl 2 -Doped N-Type Polycrystalline SnSe Through Band Engineering and Incorporating Multiple Defects

作者：Xiaowei Wu, Hong Wu, Jie Liu, Sikang Zheng, Qihong Xiong, Kaiqi Zhang, Hanjun Zou, Guiwen Wang, Guang Han, Guoyu Wang, Xu Lu, Bin Zhang, Xiaoyuan Zhou · 发表于：ACS Applied Materials & Interfaces · 年份：2025 · DOI：10.1021/acsami.4c22539 · 被引用次数：8 · 研究领域：Advanced Thermoelectric Materials and Devices、Chalcogenide Semiconductor Thin Films、Perovskite Materials and Applications

SnSe-based compounds, as promising thermoelectric materials, are well-known for their intrinsically low thermal conductivity and outstanding thermoelectric performance. However, the suboptimal electrical transport capacity for n-type polycrystalline SnSe significantly hinders the improvement of its thermoelectric performance. In this work, an effective approach for enhancing the thermoelectric performance of n-type SnSe polycrystalline materials through ZnCl 2 doping has been investigated. The enhanced density of state effective mass, which is related to the introduction of an impurity level and the facilitation of multivalley degeneracy after ZnCl 2 doping, can significantly improve the electrical transport coefficient. Additionally, multiple defects caused by ZnCl 2 doping, such as multiscale precipitates, amorphous tin chloride, and twin boundaries, effectively decrease the lattice thermal conductivity, leading to a subsequently enhanced quality factor. As a result, the SnSe 0.95 –2%ZnCl 2 sample achieves a maximum zT of ∼1.3 at 873 K parallel to the pressing direction, being 4 orders higher than that of the pristine SnSe 0.95 sample and better than that of most other halide-doped SnSe samples. This study presents a cost-effective and environmentally friendly strategy for improving the thermoelectric properties of n-type polycrystalline SnSe.