High-performance thermoelectric (TE) devices require not only a high figure of merit (ZT) but also mechanical strength and thermal stability. Here, a simultaneous enhancement of ZT as well as mechanical properties is obtained in GeTe-based alloys by adding boron. This material is then assembled with n-type CoSb₃ skutterudite into TE modules. The improved ZT values result from the increase in charge carrier mobility due to the reduced interfacial barrier height. A peak ZT of 2.2 at 773 K can be achieved in Ge_0.84Pb_0.1Sb_0.06TeB_0.07, which shows a negligible change in the coefficient of thermal expansion upon the phase transition from the rhombohedral to the cubic phase, ensuring good thermal stability of the device. Resulting from the boron-induced grain refinement and dispersion strengthening, the average compressive strength and Vickers hardness of Ge_0.9Sb_0.1TeB_0.07 can be enhanced to ≈227 MPa and ≈202 H_v, respectively. The improved mechanical properties facilitate the assembly of devices and lower the interfacial contact resistance. As a synergy of increased ZT and mechanical strength, a high output power density of ≈1.76 W cm⁻² at ΔT = 425 K and an energy conversion efficiency of 7.4% at ΔT = 477 K can be achieved in the TE modules.

中文翻译：

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用于具有高输出功率密度的坚固热电器件的硼强化 GeTe 基合金

高性能热电 (TE) 器件不仅需要高品质因数 ( ZT )，还需要机械强度和热稳定性。在这里，通过添加硼在 GeTe 基合金中获得了ZT和机械性能的同时增强。然后将该材料与 n 型 CoSb ₃方钴矿组装成 TE 模块。改进的ZT值导致从在电荷载体迁移率的增加是由于降低的界面势垒高度。Ge _0.84 Pb _0.1 Sb _0.06 TeB _0.07在 773 K 时可以达到 2.2的峰值ZT，这表明从菱形相到立方相的相变过程中热膨胀系数的变化可以忽略不计，确保了器件的良好热稳定性。由于硼诱导的晶粒细化和弥散强化，Ge _0.9 Sb _0.1 TeB _0.07的平均抗压强度和维氏硬度可以分别提高到≈227 MPa 和≈202 H _v。改进的机械性能有利于器件的组装并降低界面接触电阻。作为增加的ZT和机械强度的协同作用，在ΔT 下具有 ≈1.76 W cm ^-2的高输出功率密度 = 425 K，在 Δ T  = 477 K 时，TE 模块可以实现7.4% 的能量转换效率。