Abstract Pure phase NbFeSb1-xSnx (where x = 0, 0.04, 0.08, 0.12, 0.16) half-Heusler samples were prepared by direct mechanical alloying followed by spark plasma sintering. The results showed that the substitution of Sb by Sn can effectively enhance the peak figure of merit (ZT) to 0.55 at 923 K in NbFeSb0.88Sn0.12 through optimized carrier concentration. To further reduce the lattice thermal conductivity (κL), we substituted Nb by Hf to enhance the point defect scattering of phonon transport. A maximum reduction of ~80% in κL was observed in Nb0.8Hf0.2FeSb0.88Sn0.12 when compared to undoped NbFeSb at 573 K. We realized a minimum κL of ~2.96 W m−1 K−1 at 673 K and a peak ZT of ~0.82 at 973 K for Nb0.88Hf0.12FeSb0.88Sn0.12.

中文翻译：

---

通过 Sn/Hf 共掺杂调节 NbFeSb 半赫斯勒化合物的电子和声子特性

摘要 通过直接机械合金化和放电等离子烧结制备纯相 NbFeSb1-xSnx（其中 x = 0、0.04、0.08、0.12、0.16）半赫斯勒样品。结果表明，通过优化载流子浓度，用 Sn 替代 Sb 可以有效地将 NbFeSb0.88Sn0.12 中的峰值品质因数 (ZT) 在 923 K 处提高到 0.55。为了进一步降低晶格热导率（κL），我们用 Hf 代替 Nb 以增强声子传输的点缺陷散射。与 573 K 下未掺杂的 NbFeSb 相比，在 Nb0.8Hf0.2FeSb0.88Sn0.12 中观察到的 κL 最大减少了约 80%。我们在 673 K 下实现了约 2.96 W m-1 K-1 的最小 κL，并且Nb0.88Hf0.12FeSb0.88Sn0.12 在 973 K 时的峰值 ZT 为 ~0.82。