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<p>Thermoelectric (TE) materials enable direct thermal-electric energy conversion, but Bi<sub>2</sub>Te<sub>3</sub>-based alloys suffer from limited thermoelectric performance and controversial doping mechanisms of Cu, hindering their practical application in waste heat recovery. To address these issues, this work designs and synthesizes a series of zone-melted p-type Bi<sub>0.5</sub>Sb<sub>1.5*(1−<i>x</i>)</sub>Cu<sub>1.5*<i>x</i></sub>Te<sub>3</sub>+3 <i>wt</i>% Te (<i>x</i> = 0.0–2.0%) samples. The results show that Cu occupies interstitial sites, suppresses Te volatilization to increase the hole concentration, and enhances the electrical conductivity. Concurrently, lattice distortions and secondary phases reduced lattice thermal conductivity. The 1.0% Cu-doped sample achieves a maximum power factor of 4.74 mW·m<sup>− 1</sup>·K<sup>− 2</sup> at 300&#xa0;K, a peak <i>zT</i> of 1.03 at 412&#xa0;K, and an average <i>zT</i> of 0.91 (300–500&#xa0;K), representing improvements of 7%, 8.4%, and 18% over the undoped matrix. Subsequent hot deformation further reduced lattice thermal conductivity but did not enhance <i>zT</i> due to an anomalous rise in carrier concentration and decreased mobility. This study clarifies the interstitial Cu doping mechanism, providing a viable strategy for optimizing Bi<sub>2</sub>Te<sub>3</sub>-based materials.</p>

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Enhanced thermoelectric performance of p-type Bi0.5Sb1.5Te3 through Cu doping and zone melting

  • 期刊论文

  • 发表日期：

    2026年3月26日

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  • Xinli Du,
  • Jian Yu,
  • Shaoqiu Ke,
  • Mingxu Wei,
  • Xiurong Dong,
  • Xiaolei Nie,
  • Wanting Zhu,
  • Ping Wei,
  • Yu Zhang,
  • Danqi He,
  • Mingrui Liu,
  • Lin Hua,
  • Zhili Hu,
  • Wenyu Zhao,
  • Qingjie Zhang

摘要

Thermoelectric (TE) materials enable direct thermal-electric energy conversion, but Bi2Te3-based alloys suffer from limited thermoelectric performance and controversial doping mechanisms of Cu, hindering their practical application in waste heat recovery. To address these issues, this work designs and synthesizes a series of zone-melted p-type Bi0.5Sb1.5*(1−x)Cu1.5*xTe3+3 wt% Te (x = 0.0–2.0%) samples. The results show that Cu occupies interstitial sites, suppresses Te volatilization to increase the hole concentration, and enhances the electrical conductivity. Concurrently, lattice distortions and secondary phases reduced lattice thermal conductivity. The 1.0% Cu-doped sample achieves a maximum power factor of 4.74 mW·m− 1·K− 2 at 300 K, a peak zT of 1.03 at 412 K, and an average zT of 0.91 (300–500 K), representing improvements of 7%, 8.4%, and 18% over the undoped matrix. Subsequent hot deformation further reduced lattice thermal conductivity but did not enhance zT due to an anomalous rise in carrier concentration and decreased mobility. This study clarifies the interstitial Cu doping mechanism, providing a viable strategy for optimizing Bi2Te3-based materials.