Lattice distortion and anisotropic thermoelectric properties in hot-deformed CuI-doped Bi2Te2·7Se0.3
JOURNAL OF ALLOYS AND COMPOUNDS(2020)
摘要
We investigated anisotropic thermoelectric properties of (CuI)(x)Bi2Te2.7Se0.3 (x = 0.0, 0.3, 0.6, and 0.9 mol.%) compounds, synthesized by the hot-press and hot-deformation process. In spite of poly-crystalline compound, the hot-deformed compounds exhibit preferred orientation along the c-axis, parallel with the applied press direction. The sample of x= 0.3 mol.% shows the maximum power factor (3.8 mW m(-1) K-2 at 300 K) and ZT value (0.97 at 423 K), which is relatively high thermoelectric performance in n-type thermoelectric materials as a mild-temperature operation. Notably, the in-plane lattice thermal conductivity of the x = 0.3% compound with covalent bonding layer has lower value than the one of out-of-plane lattice thermal conductivity with van der Waals bonding layer. From the high resolution transmission electron microscopy and electron diffraction measurements, we observe the lattice distortion of the x = 0.3% compound. Therefore, the unconventional anisotropic lattice thermal conductivity can be associated with the lattice distortion along the in-plane on the compound driven by the CuI doping. (C) 2019 Elsevier B.V. All rights reserved.
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关键词
Thermoelectric,High ZT,Lattice distortion,Hot deformation
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