Influence of a Nano Phase Segregation on the Thermoelectric Properties of the p-Type Doped Stannite Compound Cu2+xZn1鈥?i>xGeSe4

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• 作者：Wolfgang G. Zeier ; Aaron LaLonde ; Zachary M. Gibbs ; Christophe P. Heinrich ; Martin Panth枚fer ; G. Jeffrey Snyder ; Wolfgang Tremel
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：April 25, 2012
• 年：2012
• 卷：134
• 期：16
• 页码：7147-7154
• 全文大小：550K
• 年卷期：v.134,no.16(April 25, 2012)
• ISSN：1520-5126

文摘

Engineering nanostructure in bulk thermoelectric materials has recently been established as an effective approach to scatter phonons, reducing the phonon mean free path, without simultaneously decreasing the electron mean free path for an improvement of the performance of thermoelectric materials. Herein the synthesis, phase stability, and thermoelectric properties of the solid solutions Cu_2+xZn_1鈥?i>xGeSe₄ (x = 0鈥?.1) are reported. The substitution of Zn²⁺ with Cu⁺ introduces holes as charge carriers in the system and results in an enhancement of the thermoelectric efficiency. Nano-sized impurities formed via phase segregation at higher dopant contents have been identified and are located at the grain boundaries of the material. The impurities lead to enhanced phonon scattering, a significant reduction in lattice thermal conductivity, and therefore an increase in the thermoelectric figure of merit in these materials. This study also reveals the existence of an insulator-to-metal transition at 450 K.