Abstract The microstructure, oxidation state and thermoelectric transport properties of Mg and Pb co-doped p -type Bi 1–2 x Mg x Pb x CuSeO oxyselenides have been investigated. Pure single BiCuSeO phase are obtained for all the samples without preferential growth in the crystallites. X-ray photoelectron spectroscopy (XPS) results indicate that both Mg and Pb dopants are in the 2+ oxidation state whereas other than the expected Bi 3+ , higher-oxidation-state Bi ions also exist in both the pristine and doped BiCuSeO compounds. The Mg and Pb co-doping yields a remarkable enhancement in the electrical conductivity coupled with a moderate Seebeck coefficient. A pronounced increment in power factor is achieved from 2.54 μW cm −1 K −2 for the pristine BiCuSeO to 11.1 μW cm −1 K −2 for Bi 0.88 Mg 0.06 Pb 0.06 CuSeO at 750 K. In addition to increasing the power factor, Mg and Pb co-doping reduces the lattice thermal conductivity owing to the dopant-induced point defect scattering of phonon. The combination of optimized power factor and intrinsically low lattice thermal conductivity results in a high Z T of 1.19 at 750 K for Bi 0.88 Mg 0.06 Pb 0.06 CuSeO, which is about 3.1 times as large as that for the pristine BiCuSeO.

中文翻译：

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共掺杂显着改善 p 型 Bi 1-2x Mg x Pb x CuSeO 氧硒化物的热电品质因数

摘要 研究了 Mg 和 Pb 共掺杂 p 型 Bi 1-2 x Mg x Pb x CuSeO 氧硒化物的微观结构、氧化态和热电传输性能。所有样品都获得了纯单 BiCuSeO 相，而没有在微晶中优先生长。X 射线光电子能谱 (XPS) 结果表明，Mg 和 Pb 掺杂剂都处于 2+ 氧化态，而除了预期的 Bi 3+ 之外，原始和掺杂的 BiCuSeO 化合物中也存在更高氧化态的 Bi 离子。Mg 和 Pb 共掺杂显着提高了电导率，同时具有适中的塞贝克系数。在 750 K 时，功率因数从原始 BiCuSeO 的 2.54 μW cm -1 K -2 到 Bi 0.88 Mg 0.06 Pb 0.06 CuSeO 的 11.1 μW cm -1 K -2 显着增加。除了提高功率因数外，Mg 和 Pb 共掺杂还降低了由于掺杂剂引起的声子点缺陷散射而导致的晶格热导率。优化的功率因数和固有的低晶格热导率相结合，导致 Bi 0.88 Mg 0.06 Pb 0.06 CuSeO 在 750 K 下的 ZT 为 1.19，约为原始 BiCuSeO 的 3.1 倍。