School of Materials Science and Engineering, Shanghai University , 99 Shangda Road, Shanghai 200444, China.
Materials Genome Institute, Shanghai University , 99 Shangda Road, Shanghai 200444, China.
ACS Appl Mater Interfaces. 2017 Mar 15;9(10):8729-8736. doi: 10.1021/acsami.6b16060. Epub 2017 Mar 3.
Thermoelectric properties of Na-doped PbTe-SrTe system have been improved by the addition of Mn. The substitution of Mn for Pb modifies the band structure of the PbTe-SrTe alloy, which enlarges the band gap and increases the valence band degeneracy. This leads to increased thermopowers and power factors near room temperature, and the electronic contribution to the total thermal conductivity is also substantially reduced due to increased resistivity. Moreover, alloying of MnTe within the PbTe matrix introduces low angle grain boundaries, and significantly reduces the lattice thermal conductivity due to the dislocation scattering. A thermoelectric figure of merit as high as 1.98 and an enhancement of the average thermoelectric figure of merit by 18% are achieved for the sample with 4 at% Mn with respect to the Mn-free sample, which can be mainly attributed to the synergistic effects of the band structure modification and the dislocation scattering on phonon transport, both induced by alloying with MnTe. Our experimental results demonstrate the promising potential of PbTe-SrTe-MnTe system for the application of waste heat recovery.
通过添加 Mn，改善了 Na 掺杂 PbTe-SrTe 体系的热电性能。Mn 取代 Pb 会改变 PbTe-SrTe 合金的能带结构，从而增大带隙并增加价带简并度。这导致在室温附近的热电势和功率因子增加，并且由于电阻率增加，电子对总热导率的贡献也大大降低。此外，MnTe 在 PbTe 基体中的合金化会引入小角度晶界，并由于位错散射而显著降低晶格热导率。与不含 Mn 的样品相比，添加 4 at% Mn 的样品的热电优值高达 1.98，平均热电优值提高了 18%，这主要归因于 MnTe 合金化引起的能带结构改性和位错散射对声子输运的协同效应。我们的实验结果表明，PbTe-SrTe-MnTe 体系在余热回收方面具有广阔的应用前景。
