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<p>The development of compatible p-type and n-type pairs within the same matrix is essential for high-efficiency thermoelectric devices. While substantial advancements have been achieved in the figure of merit for p-type GeSe, achieving high-performance n-type GeSe remains a formidable challenge due to the strong covalent bonding in the orthorhombic phase, which restricts dopant solubility, induces low cationic vacancy formation energy, and hence obstructs the critical p-to-n type transition. Here, we utilize AgBiTe<sub>2</sub> alloying to facilitate the transition of GeSe from its covalently bonded orthorhombic phase to the metavalently bonded cubic phase, thus enhancing dopability and enabling precise manipulation of point defects. The superior solubility of Bi relative to Ag in the GeSe matrix generates a dominant donor effect from Bi<sup>3+</sup>, while the concentration of anionic vacancies, particularly Te vacancies, progressively outbalances that of cationic vacancies, both of which accelerate the successful p-to-n type conversion of GeSe. By introducing a slight Te deficiency to optimize electron concentration, we attain a record-breaking <i>zT</i> of 0.51 at 723 K in n-type cubic (GeSe)<sub>0.5</sub>(AgBiTe<sub>1.93</sub>)<sub>0.5</sub>. This work not only unveils a promising route for high-performance n-type GeSe but also provides valuable insights into the interplay of chemical bonding, phase structure, dopability, and point defects in chalcogenides.</p>

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Chemical bonding-driven dopability and point defect engineering enable improved n-type GeSe thermoelectrics

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年6月16日

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  • Xinjian Li,
  • Yi Zeng,
  • Siyuan Song,
  • Huangshui Ma,
  • Tu Lyu,
  • Xiaohuan Luo,
  • Haoran Luo,
  • Moran Wang,
  • Hua-Lu Zhuang,
  • Chaohua Zhang,
  • Fusheng Liu,
  • Siqi Huo,
  • Min Hong,
  • Lipeng Hu

摘要

The development of compatible p-type and n-type pairs within the same matrix is essential for high-efficiency thermoelectric devices. While substantial advancements have been achieved in the figure of merit for p-type GeSe, achieving high-performance n-type GeSe remains a formidable challenge due to the strong covalent bonding in the orthorhombic phase, which restricts dopant solubility, induces low cationic vacancy formation energy, and hence obstructs the critical p-to-n type transition. Here, we utilize AgBiTe2 alloying to facilitate the transition of GeSe from its covalently bonded orthorhombic phase to the metavalently bonded cubic phase, thus enhancing dopability and enabling precise manipulation of point defects. The superior solubility of Bi relative to Ag in the GeSe matrix generates a dominant donor effect from Bi3+, while the concentration of anionic vacancies, particularly Te vacancies, progressively outbalances that of cationic vacancies, both of which accelerate the successful p-to-n type conversion of GeSe. By introducing a slight Te deficiency to optimize electron concentration, we attain a record-breaking zT of 0.51 at 723 K in n-type cubic (GeSe)0.5(AgBiTe1.93)0.5. This work not only unveils a promising route for high-performance n-type GeSe but also provides valuable insights into the interplay of chemical bonding, phase structure, dopability, and point defects in chalcogenides.