Lattice plainification and band sharpening through Ag doping for enhanced thermoelectric transport in polycrystalline SnS

作者：Yuxin Li, Liangsheng Wang, Tao Hong, Xiaojun Li, Heping An, Mengyue Wu, Xiaoqian Wang, Lizhong Su, Chongjian Zhou, Wenke He · 发表于：Transactions of Materials Research · 年份：2026 · DOI：10.1016/j.tramat.2026.100399 · 研究领域：Advanced Thermoelectric Materials and Devices、Chalcogenide Semiconductor Thin Films、Heusler alloys: electronic and magnetic properties

Low-cost and eco-friendly polycrystalline SnS shows great thermoelectric potential due to its intrinsically low thermal conductivity and excellent mechanical properties. However, its carrier mobility is strongly limited by multidimensional defects and a large effective mass, severely hindering the improvement of electrical performance. In this work, Ag is introduced to improve carrier mobility from two aspects, by filling intrinsic Sn vacancies to plainify the lattice (lattice plainification) and substituting for Sn atoms to sharpen the valance band (band sharpening). At the atomic scale, lattice plainification substantially reduces carrier scattering by defects, and at the electronic level, band sharpening decreases the effective mass. These two effects synergistically enhance carrier transport, resulting in a significant increase in the carrier mobility of SnS from ∼ 6.7 cm 2 V -1 s -1 to ∼ 29 cm 2 V -1 s -1 at room-temperature, along with an enhanced power factor ( PF ) over the working temperature range that peaks at ∼ 6 μW cm -1 K -2 at 473 K. Moreover, the critical roles of Ag have been directly confirmed by STEM characterization and electronic band structure calculations, respectively. Our approach yields a competitive figure of merit ( ZT ) of 0.81 at 773 K in polycrystalline SnS materials. This result highlight effective strategies for carrier mobility optimization and demonstrates its promise as a low-cost, high-efficiency thermoelectric candidate.