【作者】 曹一琦； 朱铁军； 赵新兵；

【Author】 CAO Yi-qi ZHU Tie-jun ZHAO Xin-bing (State Key Laboratory of Silicon Materials,Department of Materials Science and Engineering,Zhejiang University,Hangzhou 310027,China)

【机构】 浙江大学材料科学与工程系,硅材料国家重点实验室；

【摘要】 研究了用低温湿化学法和水热法制备纳米级的 Bi₂Te₃和 Sb₂Te₃颗粒,并通过透射电镜观察其微观形貌, Bi₂Te₃粉末的微观形貌为直径在30～50nm 之间的片状小颗粒,而 Sb₂Te₃颗粒的微观形貌为薄带状,直径约为 70nm,长度则为从150～300nm 不等,并对其晶体的形核和长大机理进行了讨论。认为,纳米小颗粒状的 Bi₂Te₃ 晶体可能是通过“表面形核和侧向生长”形成的产物,而薄带状的 Sb₂Te₃晶体可能是在 Te 块解体形成的条带状碎屑基础上形成的,用放电等离子烧结法（spark plasma sintering）制备不同比例的 Bi₂Te₃/Sb₂Te₃块状复合材料, 测量并比较了其热电性能。通过改变 Bi₂Te₃的量,可以提高复合材料的电性能,成分不同的层片间的散射,能更有效地降低块体材料的热导率。在500K 的温度下, Bi₂We₃和 Sb₂Te₃以摩尔比为1：1复合烧结的试样的热导率低达0．7W／（m·K）．进一步优化 Bi₂Te₃和 Sb₂Te₃的复合比例,其热电性能可能会有进一步的提高。更多还原

【Abstract】 Bi₂Te₃ and Sb₂Te₃ thermoelectric materials have been synthesized by low temperature aqueous chemical method in an open beaker and hydrothermal synthesis in a closed autoclave,respectively.The microstructure investigations show that the Bi₂Te₃ flakes have an average diameter of about 40nm,while about 70 nm for the Sb₂Te₃ belts, and with the length varying from about 150 to 300 nm.It indicates that the low-temperature aqueous chemical method can synthesize the nanostructure powders more easily than the hydrothermal method.Four bulk samples were prepared by spark plasma sintering with different ratios of Bi₂Te₃ and Sb₂Te₃.The materials have remarkably low thermal conductivity, the lowest thermal conductivity was found to be 0.7W/（m·K）in the sample with the ratio of Bi₂Te₃:Sb₂Te₃ of 1:1. Improved thermoelectric properties could be expected by the doping optimization of the composites.更多还原