Effects of Doping on Transport Properties in Cu鈥揃i鈥揝e-Based Thermoelectric Materials

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• 作者：Jae-Yeol Hwang ; Hyeon A. Mun ; Sang Il Kim ; Ki Moon Lee ; Jungeun Kim ; Kyu Hyoung Lee ; Sung Wng Kim
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：December 15, 2014
• 年：2014
• 卷：53
• 期：24
• 页码：12732-12738
• 全文大小：620K
• ISSN：1520-510X

文摘

The thermoelectric properties of Zn-, In-, and I-doped Cu_1.7Bi_4.7Se₈ 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+yBi_5鈥?i>ySe₈ 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 Cu_1.6915In_0.0085Bi_4.7Se₈ was achieved, yielding 30% enhancement compared with that of a pristine Cu_1.7Bi_4.7Se₈ at the same temperature.