In the pursuit of high-performance thermoelectric materials, the challenge often lies in achieving high doping concentrations, which are essential for enhancing electrical properties. Traditional doping methods may prove insufficient, as the solid solution effect is not optimal. In this study, we introduce a doping approach termed “quasi-homogenization”. This doping strategy utilizes two structurally and compositionally similar compounds, allowing for a more efficient solid solution of Ge in Cu₃SbSe₄.This approach demonstrates superior efficiency compared to prior endeavors aimed at optimizing the thermoelectric properties of Cu₃SbSe₄ through Ge doping. The efficient solid solution of Ge not only provides a substantial number of carriers, thereby enhancing the electrical properties of the material, but also induces notable changes in its microstructure. Following Ge solid solution, the material exhibits increased porosity and reduced grain size, dislocations and second phase generation. These structural modifications contribute to a significant reduction in the lattice thermal conductivity of the material. In the Cu₃SbSe₄ + 1.0 wt % Cu₂GeSe₃ sample, a peak ZT of 1.0 was attained at 723 K, while an average ZT of 0.56 was achieved within the temperature range of 323 to 723 K. Furthermore, nanoindentation tests revealed a significant enhancement in the mechanical properties of the material, evidenced by a 10% increase in hardness and a 6% increase in modulus. This work underscores the feasibility of enhancing the efficient solid solution of ternary elements through “quasi-homogenization”, a doping method that holds promise for broader applications across various ternary systems.

中文翻译：

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通过准均质掺杂在 Cu3SbSe4–Cu2GeSe3 块状材料中实现高热电和机械性能的高效固溶


在追求高性能热电材料的过程中，挑战往往在于实现高掺杂浓度，这对于增强电气性能至关重要。传统的掺杂方法可能被证明是不够的，因为固溶效果不是最佳的。在这项研究中，我们引入了一种称为“准均质化”的掺杂方法。这种掺杂策略利用了两种结构和成分相似的化合物，从而可以在 Cu₃SbSe₄ 中实现更有效的 Ge 固溶体。与之前旨在通过 Ge 掺杂优化 Cu₃SbSe₄ 的热电性能的努力相比，这种方法表现出卓越的效率。Ge 的高效固溶体不仅提供了大量的载流子，从而增强了材料的电性能，而且还诱导了其微观结构的显着变化。在 Ge 固溶体之后，该材料表现出孔隙率增加，晶粒尺寸、位错和第二相生成减小。这些结构修改有助于显著降低材料的晶格热导率。在 Cu₃SbSe₄ + 1.0 wt % Cu₂GeSe₃ 样品中，在 723 K 处达到 1.0 的峰值 ZT，而在 323 至 723 K 的温度范围内达到平均 ZT 为 0.56。此外，纳米压痕测试显示材料的机械性能显着增强，硬度增加了 10%，模量增加了 6%。 这项工作强调了通过“准均质化”增强三元元素高效固溶的可行性，这种掺杂方法有望在各种三元系统中得到更广泛的应用。