The successful application of nanotechnologies in enhancing thermoelectric properties of n-type Bi2Te3 alloys remains a formidable challenge, despite significant advancements in their p-type counterparts. The distinctive challenges inherent to n-type materials include the complex relationships between defect structures and electron concentration, and the strong anisotropy of thermoelectric properties. Electrons originate from various defect structures, such as impurity dopants, vacancies, antisite defects, and grain/domain boundaries, which sensitively varies depending on material synthesis processes. Moreover, the pronounced anisotropic nature of thermoelectric properties requires grain alignment along specific crystallographic directions. Therefore, the challenges in achieving high-performance n-type Bi2Te3 alloys lie in the difficulties of independently controlling defect structures (electron concentration), textured microstructures (electron/phonon transport property), and nanofeatures. This review aims to provide a comprehensive understanding of the difficulties and challenges associated with these aspects, and to discuss potential routes for realizing high-performance n-type Bi2Te3 alloys.

中文翻译：

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为什么提高n型Bi2Te3合金的热电性能具有挑战性？


尽管纳米技术在 p 型合金方面取得了重大进展，但成功应用纳米技术来增强 n 型 Bi2Te3 合金的热电性能仍然是一项艰巨的挑战。 n型材料固有的独特挑战包括缺陷结构和电子浓度之间的复杂关系，以及热电性能的强各向异性。电子源自各种缺陷结构，例如杂质掺杂剂、空位、反位缺陷和晶粒/域边界，这些缺陷结构根据材料合成过程而敏感地变化。此外，热电特性明显的各向异性需要沿特定晶体方向排列晶粒。因此，实现高性能n型Bi2Te3合金的挑战在于难以独立控制缺陷结构（电子浓度）、织构微观结构（电子/声子输运性质）和纳米特征。本综述旨在全面了解与这些方面相关的困难和挑战，并讨论实现高性能 n 型 Bi2Te3 合金的潜在途径。