Solution Synthesis of a New Thermoelectric Zn1-xSb Nanophase and Its Structure Determination Using Automated Electron Diffraction Tomography
Solution Synthesis of a New Thermoelectric Zn1-xSb Nanophase and Its Structure Determination Using Automated Electron Diffraction Tomography
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DOI：
10.1021/ja1035122
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发表时间：
2010-07-21
影响因子：
15
通讯作者：
Tremel, Wolfgang
中科院分区：
文献类型：
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作者：
Birkel, Christina S.;Mugnaioli, Enrico;Tremel, Wolfgang
具有特定物理性质的工程材料最近集中在10纳米尺度上的纳米不均匀性的影响。这样的特征预计会散射中波和长波声子，从而降低系统的导热性。低导热率是有效热电材料的先决条件，而挑战在于限制声子的热传输，同时不减少电荷传输。设计了一种液相法合成热电“Zn4Sb3”纳米晶，作为相偏析成ZnSb和新的Zn-Sb金属间相Zn1+ δ Sb的前驱体。我们的方法使用活化的金属纳米颗粒作为前体来合成这种金属间化合物。反应物的小粒径确保了最小的扩散路径、低激活障碍和低反应温度，从而消除了传统大规模固体合成中作为限速步骤的固-固扩散。采用自动电子衍射层析结合进动电子衍射对两相进行了结构表征。基于电子衍射数据的从头算结构解揭示了两种不同的相。在Zn-Sb相图的结构多样性中，发现了新的伪六方相Zn1+ δ Sb。
Engineering materials with specific physical properties have recently focused on the effect of nanoscopic inhomogeneities at the 10 nm scale. Such features are expected to scatter medium- and long-wavelength phonons thereby lowering the thermal conductivity of the system. Low thermal conductivity is a prerequisite for effective thermoelectric materials, and the challenge is to limit the transport of heat by phonons, without simultaneously decreasing charge transport. A solution-phase technique was devised for synthesis of thermoelectric "Zn4Sb3" nanocrystals as a precursor for phase segregation into ZnSb and a new Zn-Sb intermetallic phase, Zn1+delta Sb, in a peritectoid reaction. Our approach uses activated metal nanoparticles as precursors for the synthesis of this intermetallic compound. The small particle size of the reactants ensures minimum diffusion paths, low activation barriers, and low reaction temperatures, thereby eliminating solid-solid diffusion as the rate-limiting step in conventional bulk-scale solid-state synthesis. Both phases were identified and structurally characterized by automated electron diffraction tomography combined with precession electron diffraction. An ab initio structure solution based on electron diffraction data revealed two different phases. The new pseudo-hexagonal phase, Zn1+delta Sb, was identified and classified within the structural diversity of the Zn-Sb phase diagram.