CAS: Design and discovery of lead-free hybrid layered perovskite dielectrics

CAS：无铅混合层状钙钛矿电介质的设计和发现

• 批准号: 2003793
• 负责人: Patrick Woodward
• 金额: $ 43.53万
• 依托单位: Ohio State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2003793&HistoricalAwards=false
• 关键词: CAS; Design; discovery; lead; free

Non-Technical Abstract:Dielectric materials find widespread application in modern society. Ferroelectrics are used to make circuit elements such capacitors, antennas and filters; piezoelectrics are used in sonar and ultrasound imaging technologies; pyroelectrics are used in infrared imaging devices among other applications. The vast majority of dielectric materials are inorganic oxides, many of which contain lead. With support from the Solid State and Materials Chemistry Program and the Electronic and Photonic Materials Program in the Division of Materials Research the principle investigator and his group discover and develop new dielectric materials within the emerging family of hybrid layered perovskites, materials that are made up of alternating layers of positively charged organic cations and negatively charged, corner-connected metal-halide octahedra. Through an iterative program of synthesis and characterization the rules governing the complex crystal chemistry of these materials are studied. The new knowledge is then used to design new dielectric and magnetic materials that can serve as alternatives to the lead-based oxide dielectrics that are widely used today. In addition, authentic in-class research experiments are developed and implemented in general chemistry courses at Ohio State University that impact hundreds of students per year, introducing them to research and key materials chemistry concepts at an early stage of their college education. Finally, the graduate and undergraduate students supported by this project gain training that prepares them for successful careers in academia and industry. Technical Abstract:The research, supported by the Solid State and Materials Chemistry Program and the Electronic and Photonic Materials Program in the Division of Materials Research, can be divided into two thrust areas. The first thrust involves synthesis and characterization of layered double perovskites that contain a checkerboard pattern of 1+ and 3+ cations on the octahedral sites of the inorganic layers. When paired with the appropriate organic cations these materials are able to mimic the promising dielectric properties that have recently been seen in lead-based hybrid layered perovskites, while avoiding incorporation of toxic elements such as lead and cadmium. Phase transitions are studied to understand the structure directing forces in these materials and reveal the mechanisms by which various distortion mechanisms couple to one another. The second thrust brings a similar approach to compounds that contain magnetic cations, like Cu2+, Mn2+ and Fe2+. The research leverages the interactions between organic and inorganic layers to amplify the electrical polarization seen in polar crystals and enhance the coupling between magnetic and ferroelectric order parameters. The overarching theme of the research program is to develop an understanding of the complex crystal chemistry of these hybrid materials and use that knowledge to design and develop new ferroelectrics, antiferroelectrics, piezoelectrics, multiferroics, ferroelectric semiconductors, and related classes of multifunctional dielectric materials.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

摘要：介电材料在现代社会得到了广泛的应用。铁电体用于制造电容器、天线和滤波器等电路元件；压电材料用于声纳和超声成像技术；热释电器件被用于红外成像器件和其他应用。绝大多数电介质材料是无机氧化物，其中许多含有铅。在材料研究部固态与材料化学项目和电子与光子材料项目的支持下，首席研究员和他的团队在新兴的混合层状钙钛矿家族中发现并开发了新的介电材料，这种材料由带正电的有机阳离子和带负电的角连接金属卤化物八面体交替层组成。通过一个迭代程序的合成和表征，研究了这些材料的复杂晶体化学规律。然后，这些新知识被用于设计新的介电和磁性材料，这些材料可以作为目前广泛使用的铅基氧化物介电材料的替代品。此外，俄亥俄州立大学在普通化学课程中开发并实施了真实的课堂研究实验，每年影响数百名学生，在他们大学教育的早期阶段向他们介绍研究和关键材料化学概念。最后，该项目支持的研究生和本科生获得培训，为他们在学术界和工业界的成功职业生涯做好准备。技术摘要：该研究由材料研究部固体与材料化学方向和电子与光子材料方向支持，可分为两个重点领域。第一个任务涉及层状双钙钛矿的合成和表征，该双层钙钛矿在无机层的八面体位置上含有1+和3+阳离子的棋盘状图案。当与适当的有机阳离子配对时，这些材料能够模拟最近在铅基混合层状钙钛矿中看到的有前途的介电性能，同时避免了铅和镉等有毒元素的掺入。研究相变是为了了解这些材料的结构导向力，揭示各种变形机制相互耦合的机制。第二次推力带来了类似的方法来处理含有磁性阳离子的化合物，如Cu2+， Mn2+和Fe2+。该研究利用有机层和无机层之间的相互作用来放大极性晶体中的电极化，并增强磁性和铁电序参数之间的耦合。研究计划的首要主题是发展对这些混合材料的复杂晶体化学的理解，并利用这些知识来设计和开发新的铁电体、反铁电体、压电体、多铁体、铁电半导体和相关类别的多功能介电材料。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Exploring the Stability of Mixed-Halide Vacancy-Ordered Quadruple Perovskites

• DOI: 10.1021/acs.chemmater.0c04951
• 发表时间: 2021-03-12
• 期刊: CHEMISTRY OF MATERIALS
• 影响因子: 8.6
• 作者: Gray, Matthew B.;Majher, Jackson D.;Woodward, Patrick M.
• 通讯作者: Woodward, Patrick M.

Exploring the AgSb1−xBixI4 phase diagram: Thermochromism in layered CdCl2-type semiconductors

• DOI: 10.1016/j.jssc.2021.121997
• 发表时间: 2021-05
• 期刊: Journal of Solid State Chemistry
• 影响因子: 3.3
• 作者: M. Gray;Eric T. McClure;N. Holzapfel;Felipe Pacci Evaristo;W. Windl;P. Woodward