Enhancing the thermoelectric performance of n-type polycrystalline SnSe is essential, addressing challenges posed by elevated thermal conductivity and compromised power factor inherent in its intrinsic p-type characteristics. This investigation utilized solid-state reactions and spark plasma sintering techniques for the synthesis of n-type SnSe. A significant improvement in the figure of merit (ZT) is achieved through strategic reduction in Se concentration and optimization of crystal orientation. The co-doping with Br and Ge further improves the material; Br amplifies carrier concentration, enhancing electrical conductivity, while Ge introduces effective phonon scattering centers. In the Br/Ge co-doped SnSe sample, thermal conductivity dropped to 0.38 Wm⁻¹K⁻¹, yielding a remarkable power factor of 662 µW mK⁻² at 773 K, culminating in a ZT of 1.34. This signifies a noteworthy 605% improvement over the pristine sample, underscoring the pivotal role of Ge doping in enhancing n-type material thermoelectric properties. The enhancement is attributed to Br doping introducing additional electronic states near the valence band, and Ge doping modifying the band structure, fostering resonant states near the conduction band. The Br/Ge co-doping further transforms the band structure, influencing electrical conductivity, Seebeck coefficient, and thermal conductivity, advancing the understanding and application of n-type SnSe materials for superior thermoelectric performance.

中文翻译：

---

阴离子/阳离子共掺杂提高富锡n型SnSe多晶的热电性能并抑制晶格热导率

增强 n 型多晶 SnSe 的热电性能至关重要，以解决其固有 p 型特性中固有的导热率升高和功率因数降低带来的挑战。这项研究利用固态反应和放电等离子体烧结技术来合成 n 型 SnSe。通过策略性降低 Se 浓度和优化晶体取向，实现了品质因数 (ZT) 的显着改善。 Br和Ge的共掺杂进一步改善了材料； Br 放大载流子浓度，增强电导率，而 Ge 则引入有效的声子散射中心。在 Br/Ge 共掺杂 SnSe 样品中，热导率降至 0.38 Wm-1K-1，在 773 K 时产生 662 µW mK ^{- 2}的出色功率因数，最终ZT为 1.34。这意味着比原始样品显着提高了 605%，强调了 Ge 掺杂在增强 n 型材料热电性能方面的关键作用。这种增强归因于 Br 掺杂在价带附近引入了额外的电子态，而 Ge 掺杂改变了能带结构，促进了导带附近的谐振态。 Br/Ge共掺杂进一步改变了能带结构，影响了电导率、塞贝克系数和热导率，促进了对n型SnSe材料卓越热电性能的理解和应用。