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<p>Low-symmetry thermoelectric material GeSe exhibits inherently low thermal conductivity but suppressed electrical transport properties. Here, we demonstrate that Mn doping in AgBiTe<sub>2</sub>-alloyed rhombohedral GeSe introduces band engineering and further significantly enhances lattice symmetry. Mn-induced resonant energy levels enhance the density of states effective mass and significantly optimize the Seebeck coefficient. Crucially, elevated lattice symmetry reduces deformation potential and weakens phonon-electron coupling, triggering a 185% surge in carrier mobility despite a ~1.2-fold increase in the effective mass. The synergistically optimized Seebeck coefficient and electrical conductivity enable the high-symmetry (GeMn<sub>0.005</sub>Se)<sub>0.9</sub>(AgBiTe<sub>2</sub>)<sub>0.1</sub> sample to achieve a record average power factor of ~17 μW cm<sup>−1</sup> K<sup>−2</sup> over 300–673 K while retaining low lattice thermal conductivity. Consequently, a maximum <i>ZT</i> of ~1.50 at 673 K and an average <i>ZT</i> of ~0.94 (300–673 K) are achieved, yielding a single-leg thermoelectric conversion efficiency of ~6.1% under a temperature difference of 325 K. This lattice symmetry manipulation through rational doping provides a universal pathway to promote phonon-electron decoupling and enhances thermoelectric performance in low-symmetry thermoelectric materials.</p>

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Enhanced Lattice Symmetry via Mn Doping Boosts Electrical Transport Performance in Rhombohedral GeSe Thermoelectric Materials

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年11月24日

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  • Sining Wang,
  • Yi Wen,
  • Shulin Bai,
  • Lizhong Su,
  • Yongxin Qin,
  • Yingcai Zhu,
  • Yaokun Wang,
  • Yuting Qiu,
  • Li-Dong Zhao

摘要

Low-symmetry thermoelectric material GeSe exhibits inherently low thermal conductivity but suppressed electrical transport properties. Here, we demonstrate that Mn doping in AgBiTe2-alloyed rhombohedral GeSe introduces band engineering and further significantly enhances lattice symmetry. Mn-induced resonant energy levels enhance the density of states effective mass and significantly optimize the Seebeck coefficient. Crucially, elevated lattice symmetry reduces deformation potential and weakens phonon-electron coupling, triggering a 185% surge in carrier mobility despite a ~1.2-fold increase in the effective mass. The synergistically optimized Seebeck coefficient and electrical conductivity enable the high-symmetry (GeMn0.005Se)0.9(AgBiTe2)0.1 sample to achieve a record average power factor of ~17 μW cm−1 K−2 over 300–673 K while retaining low lattice thermal conductivity. Consequently, a maximum ZT of ~1.50 at 673 K and an average ZT of ~0.94 (300–673 K) are achieved, yielding a single-leg thermoelectric conversion efficiency of ~6.1% under a temperature difference of 325 K. This lattice symmetry manipulation through rational doping provides a universal pathway to promote phonon-electron decoupling and enhances thermoelectric performance in low-symmetry thermoelectric materials.