锗相的存在对Sr_8Ga_(16)Ge_(30) clathrates结构热电材料性能的影响

• 作 者: 王丽 赵德刚 侯小伟 史啸亚 孙正亮 江莞 陈立东
• 机 构: 中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室,中国科学院研究生院,
• 出 处: 稀有金属材料与工程
• 发表日期: 2009年S2期
• 关键词: clathrate结构 热电性能 锗 clathrate structure thermoelectric properties germanium (Ge)

无机clathrate结构化合物是非常有前景的热电材料。在镓取代的锗基clathrate结构热电材料的合成中,普遍存在锗的第二相。本研究合成了多晶Sr8Ga16Ge30clathrates结构热电材料。用X射线衍射结合样品抛光表面的背散射电子像对样品中锗相的含量进行表征。测试可知,材料表现为n型半导体,随着Ge相含量的增大,Seebeck系数绝对值增大,电导和热导率减小。功率因子最大为12.8μW.K-2cm-1。Sr8Ga16Ge30样品在650K的最大ZT值达到0.65。

Inorganic clathrate structural compounds are very promising thermoelectric materials. In the synthesis of gallium substituted germanium-based clathrate structure thermoelectric materials, the second phase of germanium is prevalent. In this study, polycrystalline Sr8Ga16Ge30clathrates thermoelectric materials were synthesized. The content of germanium phase in the sample was characterized by X-ray diffraction combined with the backscattered electron image of the polished surface of the sample. The results show that the material behaves as an n-type semiconductor. As the content of Ge phase increases, the absolute value of Seebeck coefficient increases, and the electrical conductivity and thermal conductivity decrease. The maximum power factor is 12.8μW.K-2cm-1. The maximum ZT value of the Sr8Ga16Ge30 sample at 650K reached 0.65.