Effects of doping on transport properties in Cu-Bi-Se-based thermoelectric materials.
Effects of doping on transport properties in Cu-Bi-Se-based thermoelectric materials.
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DOI：
10.1021/ic5014945
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发表时间：
2014-11
影响因子：
4.6
通讯作者：
Jae-Yeol Hwang;Hyeona Mun;Sang Il Kim;K. Lee;Jungeun Kim;Kyu Hyoung Lee;Sung Wng Kim
中科院分区：
文献类型：
--
作者：
Jae-Yeol Hwang;Hyeona Mun;Sang Il Kim;K. Lee;Jungeun Kim;Kyu Hyoung Lee;Sung Wng Kim
在 300 至 560 K 的温度范围内研究了 Zn、In 和 I 掺杂的 Cu1.7Bi4.7Se8 长方石同系物的热电性质。在使用 Rietveld 精修同步辐射衍射对具有固有无序晶体位点的 Cu(x+y)Bi(5-y)Se8 化合物进行全面结构分析的基础上，我们证明了 掺杂策略通过优化载流子浓度来同时控制增强的电子传输性能，并通过形成点缺陷来提供极低的晶格热导率。 Cu 位点上的取代 Zn 或 In 离子被发现是有效的声子散射中心以及电子供体，而 Bi 位点上的掺杂对声子散射表现出中等影响。此外，通过增加电导率和适度降低塞贝克系数，我们在铜位点掺杂少量In，从而大大提高了功率因数。再加上由主体 Cu 离子取代 In 离子增强点缺陷声子散射所产生的低晶格热导率，Cu1.6915In0.0085Bi4.7Se8 在 560 K 下的热电品质因数 ZT 达到 0.24，与相同温度下的原始 Cu1.7Bi4.7Se8 相比，热电品质因数 ZT 提高了 30%。
The thermoelectric properties of Zn-, In-, and I-doped Cu1.7Bi4.7Se8 pavonite homologues were investigated in the temperature range from 300 to 560 K. On the basis of the comprehensive structural analysis using Rietveld refinement of synchrotron radiation diffraction for Cu(x+y)Bi(5-y)Se8 compounds with the inherently disordered crystallographic sites, we demonstrate a doping strategy that provides a simultaneous control for enhanced electronic transport properties by the optimization of carrier concentration and exceptionally low lattice thermal conductivity by the formation of point defects. Substituted Zn or In ions on Cu site was found to be an effective phonon scattering center as well as an electron donor, while doping on Bi site showed a moderate effect for phonon scattering. In addition, we achieved largely enhanced power factor in small amount of In doping on Cu site by increased electrical conductivity and moderately decreased Seebeck coefficient. Coupled with a low lattice thermal conductivity originated from intensified point defect phonon scattering by substituted In ions with host Cu ions, a thermoelectric figure of merit ZT of 0.24 at 560 K for Cu1.6915In0.0085Bi4.7Se8 was achieved, yielding 30% enhancement compared with that of a pristine Cu1.7Bi4.7Se8 at the same temperature.