Wei Qiang-Lin, Zhu Xue-Liang, Liu Peng-Fei, Wu Yi-Yuan, Ma Jiang-Jiang, Liu Yi-Bao, Li Yu-Hong, Wang Bao-Tian
School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China.
Phys Chem Chem Phys. 2021 Mar 21;23(11):6388-6396. doi: 10.1039/d1cp00469g. Epub 2021 Mar 11.
Through first-principles calculations, we report the thermoelectric properties of two-dimensional (2D) hexagonal group-IV tellurides XTe (X = Ge, Sn and Pb), with quadruple layers (QL) in the Te-X-X-Te stacking sequence, as promising candidates for mid-temperature thermoelectric (TE) materials. The results show that 2D PbTe exhibits a high Seebeck coefficient (∼1996 μV K) and a high power factor (6.10 × 10 W K m s) at 700 K. The lattice thermal conductivities of QL GeTe, SnTe and PbTe are calculated to be 2.29, 0.29 and 0.15 W m K at 700 K, respectively. Using our calculated transport parameters, large values of the thermoelectric figure of merit (ZT) of 0.67, 1.90, and 2.44 can be obtained at 700 K under n-type doping for 2D GeTe, SnTe, and PbTe, respectively. Among the three compounds, 2D PbTe exhibits low average values of sound velocity (0.42 km s), large Grüneisen parameters (∼2.03), and strong phonon scattering. Thus, 2D PbTe shows remarkable mid-temperature TE performance with a high ZT value under both p-type (2.39) and n-type (2.44) doping. The present results may motivate further experimental efforts to verify our predictions.
通过第一性原理计算，我们报道了二维（2D）六方IV族碲化物XTe（X = Ge、Sn和Pb）在Te-X-X-Te堆叠序列中具有四层（QL）的热电性能，它们是中温热电（TE）材料的有前途的候选者。结果表明，二维PbTe在700 K时表现出高塞贝克系数（约1996 μV K）和高功率因子（6.10×10 W K m s）。QL GeTe、SnTe和PbTe在700 K时的晶格热导率分别计算为2.29、0.29和0.15 W m K。使用我们计算的输运参数，在700 K下对二维GeTe、SnTe和PbTe进行n型掺杂时，热电优值（ZT）分别可获得0.67、1.90和2.44的大值。在这三种化合物中，二维PbTe表现出低的平均声速值（0.42 km s）、大的格林艾森参数（约2.03）和强的声子散射。因此，二维PbTe在p型（2.39）和n型（2.44）掺杂下均表现出具有高ZT值的卓越中温TE性能。目前的结果可能会促使进一步的实验努力来验证我们的预测。
