Traveling solvent crystal growth of anisotropic Zintl thermoelectrics.

各向异性 Zintl 热电材料的流动溶剂晶体生长。

• 批准号: 1709158
• 负责人: Alexandra Zevalkink
• 金额: $ 32.88万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1709158&HistoricalAwards=false
• 关键词: Traveling; solvent; crystal; growth; anisotropic

Part 1: Non-Technical SummaryThermoelectric materials are used to convert heat into electricity. They have applications ranging from industrial waste-heat recovery, to remote sensing, to space exploration. High efficiency thermoelectric materials need to simultaneously exhibit high electrical conductivity, a large Seebeck coefficient and low thermal conductivity. This combination of properties is exceptionally difficult to achieve. Materials with highly anisotropic crystal structures offer a potential strategy to increase the thermoelectric efficiency, because their physical properties display different values when measured along different crystallographic directions. The goal of the research funded by this award from the Solid State and Materials Chemistry program is to develop a powerful and adaptable method for single crystal growth of compounds with complex, anisotropic crystal structures. Characterizing these large crystals advances our understanding of the fundamental connection between the atomic structure of materials and the anisotropic thermal and electronic behavior, providing routes to enhanced thermoelectric efficiency. This interdisciplinary and collaborative project utilizes facilities at the NSF-supported PARADIM Materials Innovation Platform. With this Solid State and Materials Chemistry funded award graduate and undergraduate students are trained in solid state synthesis and physics of materials; the principal investigator also leverages results from this grant for outreach activities such as the 'Introduce a Girl to Engineering' day, the 'Lady Spartans Engineering Summer Camp' and in-class activities at local high schools. Part 2: Technical SummaryThe research for this award is based on the understanding that one of the most fundamental conflicts in the design of thermoelectric materials - the need for simultaneous high electronic mobility and a high density of states near the Fermi level - can be circumvented by exploiting anisotropic electronic transport. Zintl intermetallic phases, with their vast structural variety and excellent high-temperature thermoelectric performance, stand out as an intriguing subject area for the study of thermal and electronic transport anisotropy. Although theoretical studies predict significant thermoelectric efficiency gains along the covalently-bonded, high-conductivity directions in some Zintl phases, experimental confirmation is lacking due to the difficulty of growing single crystals suitable for transport measurements. With this grant from the Solid State Materials Chemistry program the principal investigator aims to bridge this gap between theory and experiment by adapting the traveling-solvent floating-zone (TSFZ) crystal growth technique to the growth of large Zintl single crystals. The TSFZ technique is a crucible-less method that combines flux growth and directional solidification and is particularly well-suited for refractory compounds with incongruent melting transitions. It is a natural extension of flux growth - a historically successful method for the growth of Zintl crystals - but it allows for the growth of larger crystals suitable for transport measurements. Zintl antimonides, which exhibit high thermoelectric efficiency even in polycrystalline form, are the focus of this work. Characterization of the grown crystals combined with first principles investigations are used to explore the link between polyanion dimensionality and transport, with an emphasis on the anisotropy of electron and phonon velocities and scattering rates. This project applies a closed-loop approach to material design and selection by directly validating theoretical predictions, thus leading to a more complete picture of anisotropic transport behavior in complex semiconductors used in a broad range of applications. At the same time results from this research are leveraged for outreach activities such as the 'Introduce a Girl to Engineering' day, the 'Lady Spartans Engineering Summer Camp' and in-class activities at local high schools.

第1部分：非技术概述热电材料用于将热转化为电。它们的应用范围从工业废热回收到遥感，再到空间探索。高效热电材料需要同时具有高导电性、大塞贝克系数和低导热性。这种性质的结合是非常难以实现的。具有高度各向异性晶体结构的材料提供了一种潜在的提高热电效率的策略，因为它们的物理性质在沿着不同的晶体学方向测量时显示不同的值。这项由固态和材料化学项目资助的研究的目标是开发一种强大的、适应性强的方法，用于具有复杂、各向异性晶体结构的化合物的单晶生长。表征这些大晶体促进了我们对材料原子结构与各向异性热和电子行为之间基本联系的理解，为提高热电效率提供了途径。这个跨学科的合作项目利用了nsf支持的PARADIM材料创新平台的设施。通过固态和材料化学资助的奖项，研究生和本科生在固态合成和材料物理方面进行培训；首席研究员还利用这笔拨款的成果开展外展活动，如“介绍女孩接触工程”日、“斯巴达女士工程夏令营”和当地高中的课堂活动。本奖项的研究基于这样一种认识，即热电材料设计中最基本的冲突之一-同时需要高电子迁移率和费米能级附近的高密度态-可以通过利用各向异性电子输运来规避。Zintl金属间相具有丰富的结构多样性和优异的高温热电性能，是研究热电输运各向异性的一个有趣的课题。虽然理论研究预测在一些Zintl相中沿共价键、高导电性方向有显著的热电效率提高，但由于难以生长适合输运测量的单晶，缺乏实验证实。在固态材料化学项目的资助下，首席研究员的目标是通过采用流动溶剂漂浮区（TSFZ）晶体生长技术来生长大的Zintl单晶，从而弥合理论和实验之间的差距。TSFZ技术是一种无坩埚的方法，结合了通量增长和定向凝固，特别适合于具有不一致熔化转变的难熔化合物。这是通量生长的自然延伸——历史上一种成功的Zintl晶体生长方法——但它允许生长适合输运测量的更大的晶体。锑化锌即使在多晶形式下也表现出较高的热电效率，是本研究的重点。结合第一性原理研究，利用生长晶体的表征来探索聚阴离子维度与输运之间的联系，重点研究了电子和声子速度和散射率的各向异性。该项目通过直接验证理论预测，将闭环方法应用于材料设计和选择，从而更全面地了解广泛应用的复杂半导体的各向异性输运行为。与此同时，这项研究的结果被用于推广活动，如“介绍一个女孩到工程”日，“斯巴达女士工程夏令营”和当地高中的课堂活动。

项目成果

An Unlikely Route to Low Lattice Thermal Conductivity: Small Atoms in a Simple Layered Structure

• DOI: 10.1016/j.joule.2018.06.014
• 发表时间: 2018-09-19
• 期刊: JOULE
• 影响因子: 39.8
• 作者: Peng, Wanyue;Petretto, Guido;Zevalkink, Alexandra
• 通讯作者: Zevalkink, Alexandra

Thermoelectric Properties of Scandium Sesquitelluride

• DOI: 10.3390/ma12050734
• 发表时间: 2019-03-01
• 期刊: MATERIALS
• 影响因子: 3.4
• 作者: Cheikh, Dean;Lee, Kathleen;Bux, Sabah K.
• 通讯作者: Bux, Sabah K.

Investigation of (001), (010), and (100) Surface Termination and Surface Energies of the Zintl Ca5Ga2Sb6

• DOI: 10.1016/j.susc.2021.121918
• 发表时间: 2021-08
• 期刊: Surface Science
• 影响因子: 1.9
• 作者: Monique N. Noel;David M. Smiadak;Jie Pan;Y. Qi;A. Zevalkink

Single crystal growth and characterization of new Zintl phase Ca9Zn3.1In0.9Sb9

• DOI: 10.1016/j.jssc.2020.121947
• 发表时间: 2021-01
• 期刊: Journal of Solid State Chemistry
• 影响因子: 3.3
• 作者: David M. Smiadak;S. Baranets;Megan Rylko;M. Marshall;Mario Calderón-Cueva;S. Bobev;A. Zevalkink

Ultralow Thermal Conductivity in Diamond-Like Semiconductors: Selective Scattering of Phonons from Antisite Defects

类金刚石半导体中的超低导热率：反位缺陷选择性散射声子

• DOI: 10.1021/acs.chemmater.8b00890
• 发表时间: 2018
• 期刊: Chemistry of Materials
• 影响因子: 8.6
• 作者: Ortiz, Brenden R.;Peng, Wanyue;Gomes, Lídia C.;Gorai, Prashun;Zhu, Taishan;Smiadak, David M.;Snyder, G. Jeffrey;Stevanović, Vladan;Ertekin, Elif;Zevalkink, Alexandra
• 通讯作者: Zevalkink, Alexandra