Grain boundary decoration by electroless plating Ag enhances the thermoelectric performance of polycrystalline SnSe

作者：Zhizhi Wang, Xinjian Hu, Haiyan Lyu, Ming Liu, Zhang Zhang, Junping Li, Haoyuan He, Chaohua Zhang, Yuan Yu · 发表于：Journal of Alloys and Compounds · 年份：2025 · DOI：10.1016/j.jallcom.2025.179125 · 被引用次数：4 · 研究领域：Advanced Thermoelectric Materials and Devices、Chalcogenide Semiconductor Thin Films、Quantum Dots Synthesis And Properties

Tin selenide (SnSe) is a rising-start thermoelectric compound that holds record-high ZT values for bulk thermoelectrics. Yet, the performance of polycrystalline SnSe is significantly lower than that of monocrystalline SnSe due to the presence of grain boundaries (GBs). Thus, tailoring the microstructures and properties at GBs provides a route to tuning the overall thermoelectric performance. In this work, different GB phases associated with different properties are introduced in polycrystalline SnSe through chemical plating Ag. Two different phases, i.e., AgSnSe 2 and Ag 8 SnSe 6 are formed at the GB by controlling the content of Ag. While AgSnSe 2 dominates with the Ag content below 0.08 wt%, Ag 8 SnSe 6 is more prominent in the sample with 0.1 wt% Ag. Both phases improve the electrical conductivity and power factor of the material due to the reduced GB resistance. However, the thermal conductivity is also increased with the presence of AgSnSe 2 . In contrast, the formation of Ag 8 SnSe 6 further lowers the thermal conductivity of polycrystalline SnSe owing to the intrinsically ultralow thermal conductivity of Ag 8 SnSe 6 . As a result, a more significant enhancement of ZT is achieved with the presence of Ag 8 SnSe 6 at GBs. Our work provides a facile way to tune the transport properties at GBs by controlling the chemical plating process, which can be easily adapted to other polycrystalline materials. • A facile electroless plating method is used to tune the grain boundary p...