Enhanced Thermoelectric Performance of N ‐Type SnS‐Based Polycrystals Enabled by Pb Alloying and Texture Engineering
Chun Yan, Hong Wu, Peng Chen, Tian Xie, Lei Wu, Bin Zhang, Yang Shao, Guiwen Wang, Guangqian Ding, Jun Liu, Yun Zhou, Xu Lu, Yanci Yan, Dengfeng LiABSTRACT
Recently, remarkable research progress in p ‐type SnS has been achieved through effective strategies, enabling its promising application potential in the thermoelectric field. However, optimizing the thermoelectric performance of n ‐type analogues remains challenging owing to limited doping efficiency. Here, it is found that Pb alloying effectively optimizes the electron density and enhances the density of states effective mass, thereby significantly improving the power factor. Meanwhile, Pb alloying remarkably reduces phonon group velocity and strengthens lattice anharmonicity verified by theoretical calculations, together with fabricated massive point defects, giving rise to a pronounced suppression of lattice thermal conductivity. Consequently, an outstanding zT value of ∼ 0.5 at 873 K is achieved in 2.5%PbBr 2 doped Sn 0.6 Pb 0.4 S sample. Furthermore, texture engineering is employed to manipulate the microstructural texture of 2.5%PbBr 2 ‐doped Sn 0.6 Pb 0.4 S sample, enabling more effective utilization of its unique three‐dimensional (3D) charge and two‐dimensional (2D) phonon transport behavior along the interlayer direction. Ultimately, a lower lattice thermal conductivity, together with modestly improved electrical properties, is achieved through texture engineering, delivering obviously enhanced quality factor and a peak zT of ∼ 0.6 at 873 K. This work not only advances the research progress of n ‐type SnS‐based compounds, but also sheds light on optimizing thermoelectric performance of other low‐dimensional materials.