Sb₂Si₂Te₆ is a promising 2D material for medium-temperature thermoelectric applications, with the thermoelectric figure of merit zT approaching 1 at 823 K. However, its widespread use has been limited by relatively low power factor values. In this study, we successfully enhanced the performance of Sb₂Si₂Te₆ by introducing Yttrium nanocomposites. This modification fine-tuned the carrier concentration and electrical conductivity, and increased the power factor up to 946 μW K⁻¹ at 570 K. Jonker plot analysis revealed that increased carrier concentration did not affect the intrinsic electronic properties. SEM and TEM analyses revealed that Y nano-compositing introduced secondary phases, reducing the lattice thermal conductivity to values close to simulated ones using the Debye–Callaway model. Sb_1.98Y_0.02Si₂Te₆ exhibited the highest zT of 1.49 at 773 K due to the ultralow lattice thermal conductivity of 0.29 W m⁻¹ K⁻¹ and a moderate power factor of 858 μW K⁻¹ at the same temperature. The single parabolic band (SPB) model suggests that with further optimization of the Fermi level and additional reduction in lattice thermal conductivity, the zT value could potentially increase to 1.55. These results demonstrate the potential of Y nanocompositing for enhancing Sb₂Si₂Te₆ as an efficient medium-temperature thermoelectric material.

中文翻译：

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通过钇诱导纳米合成提高 Sb2Si2Te6 的热电效率


Sb₂Si₂Te₆ 是一种很有前途的中温热电应用二维材料，在 823 K 时热电品质因数 zT 接近 1。然而，它的广泛使用受到相对较低的功率因数值的限制。在这项研究中，我们通过引入钇纳米复合材料成功地提高了 Sb₂Si₂Te₆ 的性能。这种修改微调了载流子浓度和电导率，并在 570 K 时将功率因数提高到 946 μW ^K-1。Jonker 图分析表明，载流子浓度的增加不会影响本征电子特性。SEM 和 TEM 分析表明，Y 纳米合成引入了第二相，将晶格热导率降低到接近使用 Debye-Callaway 模型的模拟值。由于 Sb_1.98Y_0.02Si_{2 Te6} 在 773 K 时表现出最高的 zT，为 1.49，这是由于 0.29 W ^{m-1 K-1} 的超低晶格热导率和 858 μW ^K-1 的中等功率因数在相同的温度下。单抛物线带 （SPB） 模型表明，随着费米能级的进一步优化和晶格热导率的进一步降低，zT 值可能会增加到 1.55。 这些结果表明了 Y 纳米合成在增强 Sb₂Si₂Te₆ 作为高效中温热电材料方面的潜力。