Effect of Isovalent Substitution on the Thermoelectric Properties of the Cu2ZnGeSe4–xSx Series of Solid Solutions

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• 作者：Christophe P. Heinrich ; Tristan W. Day ; Wolfgang G. Zeier ; G. Jeffrey Snyder ; Wolfgang Tremel
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：January 8, 2014
• 年：2014
• 卷：136
• 期：1
• 页码：442-448
• 全文大小：466K
• ISSN：1520-5126

文摘

Knowledge of structure鈥損roperty relationships is a key feature of materials design. The control of thermal transport has proven to be crucial for the optimization of thermoelectric materials. We report the synthesis, chemical characterization, thermoelectric transport properties, and thermal transport calculations of the complete solid solution series Cu₂ZnGeSe_4鈥?i>xS_x (x = 0鈥?). Throughout the substitution series a continuous Vegard-like behavior of the lattice parameters, bond distances, optical band gap energies, and sound velocities are found, which enables the tuning of these properties adjusting the initial composition. Refinements of the special chalcogen positions revealed a change in bonding angles, resulting in crystallographic strain possibly affecting transport properties. Thermal transport measurements showed a reduction in the room-temperature thermal conductivity of 42% triggered by the introduced disorder. Thermal transport calculations of mass and strain contrast revealed that 34% of the reduction in thermal conductivity is due to the mass contrast only and 8% is due to crystallographic strain.