SnSe-based thermoelectric materials are being explored since they have potential high thermoelectric figure of merit. We synthesized polycrystalline Al_xSn_1-xSe (x = 0.01, 0.02, 0.03 and 0.04) by hot-pressing method, and combined theoretical estimation with experimental measurement to investigate the influence of Al doping on thermoelectric properties of SnSe. It was found that dopant Al can effectively adjust the band structure of SnSe by introducing intermediate band. Al doping with low content (x = 0.01 and 0.02) can introduce a single intermediate band close to the valence band maximum or conduction band minimum, achieving band engineering optimization. In high temperature region (498 K < T < 823 K), the electronic transport properties significantly enhance with thermal excitation. The lattice thermal conductivity reduces with the Al atomic point defect scattering, leading to a low thermal conductivity of 0.47 W m⁻¹K⁻¹ in Al_0.04Sn_0.96Se at 823 K. As a result, a high ZT of 0.84 at 823 K is obtained from the Al_0.04Sn_0.96Se perpendicular to the pressing direction, which is 58.5% larger than that of SnSe. In addition, dopant Al can adjust the anisotropy of polycrystalline SnSe. The anisotropy of electronic properties are enhanced with low doping level (x = 0.01, 0.02) and suppressed with high doping level (x = 0.03, 0.04).

正在探索基于 SnSe 的热电材料，因为它们具有潜在的高热电品质因数。我们采用热压法合成了多晶Al _x Sn _1-x Se（x = 0.01、0.02、0.03和0.04），并结合理论估计和实验测量研究了Al掺杂对SnSe热电性能的影响。发现掺杂剂Al通过引入中间能带可以有效调节SnSe的能带结构。低含量的Al掺杂（x = 0.01和0.02）可以引入接近价带最大值或导带最小值的单个中间带，实现能带工程优化。在高温区（498 K <  T < 823 K)，电子传输特性随着热激发显着增强。晶格热导率随着 Al 原子点缺陷散射而降低，导致Al _0.04 Sn _0.96 Se 在 823 K 时的低热导率为 0.47 W m ^-1 K ^-1。结果，在 823 K 时ZT为 0.84由垂直于压制方向的Al _0.04 Sn _0.96 Se 获得，比SnSe 大58.5%。此外，掺杂剂Al可以调节多晶SnSe的各向异性。低掺杂水平（x = 0.01, 0.02）增强了电子特性的各向异性，而高掺杂水平（x = 0.03, 0.04）则抑制了电子特性的各向异性。