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<p>Elemental doping plays a crucial role in optimizing carrier concentration and suppressing lattice thermal conductivity in thermoelectric materials. In this study, Cu atoms were doped in both n- and p-type Mg<sub>3</sub>Sb<sub>2</sub>-based thermoelectric compounds. The results indicate that the incorporation of Cu effectively improves the electrical transport properties of Mg<sub>3</sub>Sb<sub>2</sub>-based thermoelectric compounds while simultaneously suppressing their thermal transport, ultimately achieving enhanced thermoelectric properties: (a) For p-type Mg<sub>3</sub>Sb<sub>2</sub>, a small quantity of Cu atoms provides electrons in the lattice interstitial and thus compensates holes, leading to a decreased carrier concentration and electrical conductivity. However, with increasing Cu content, Cu atoms preferentially occupy Mg2 sites, thereby increasing hole concentration, and thus improving electrical conductivity. Further increasing Cu content, an MgCuSb secondary phase forms, which is unfavorable for overall p-type thermoelectric performance of the Mg<sub>3</sub>Sb<sub>2</sub>-based matrix due to the n-type transport of the MgCuSb compound. (b) For n-type Mg<sub>3</sub>Sb<sub>2</sub>, no such secondary phase was observed despite the same Cu-doping content, which involves a distinct doping mechanism from the p-type one. Consequently, the <i>zT</i> values of p-type Mg<sub>3</sub>Sb<sub>2</sub> materials are improved by 17%–33% over the whole temperature range. And regarding the n-type Mg<sub>3</sub>Sb<sub>2</sub> materials, the highest peak <i>zT</i> value of ~1.4 and average <i>zT</i><sub>avg</sub> of ~1.04 are achieved. Therefore, the doping of the Cu element proves to be an effective way in optimizing thermoelectric properties of both p-type and n-type Mg<sub>3</sub>Sb<sub>2</sub>-based materials.</p>

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The role of Cu in the thermoelectric transport properties of Mg3Sb2-based materials

  • 期刊论文

  • 发表日期：

    2026年5月18日

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  • Peifeng Ren,
  • Xingchen Gao,
  • Wenhao Fan,
  • Qiang Zhang,
  • Shaoping Chen,
  • Jianfeng Fan

摘要

Elemental doping plays a crucial role in optimizing carrier concentration and suppressing lattice thermal conductivity in thermoelectric materials. In this study, Cu atoms were doped in both n- and p-type Mg3Sb2-based thermoelectric compounds. The results indicate that the incorporation of Cu effectively improves the electrical transport properties of Mg3Sb2-based thermoelectric compounds while simultaneously suppressing their thermal transport, ultimately achieving enhanced thermoelectric properties: (a) For p-type Mg3Sb2, a small quantity of Cu atoms provides electrons in the lattice interstitial and thus compensates holes, leading to a decreased carrier concentration and electrical conductivity. However, with increasing Cu content, Cu atoms preferentially occupy Mg2 sites, thereby increasing hole concentration, and thus improving electrical conductivity. Further increasing Cu content, an MgCuSb secondary phase forms, which is unfavorable for overall p-type thermoelectric performance of the Mg3Sb2-based matrix due to the n-type transport of the MgCuSb compound. (b) For n-type Mg3Sb2, no such secondary phase was observed despite the same Cu-doping content, which involves a distinct doping mechanism from the p-type one. Consequently, the zT values of p-type Mg3Sb2 materials are improved by 17%–33% over the whole temperature range. And regarding the n-type Mg3Sb2 materials, the highest peak zT value of ~1.4 and average zTavg of ~1.04 are achieved. Therefore, the doping of the Cu element proves to be an effective way in optimizing thermoelectric properties of both p-type and n-type Mg3Sb2-based materials.