CAREER: Ligand Engineering of Structure and Electronic Function in Complex Metal Oxyfluorides

职业：复杂金属氟氧化物结构和电子功能的配体工程

• 批准号: 1454688
• 负责人: James Rondinelli
• 金额: $ 50万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2021-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1454688&HistoricalAwards=false
• 关键词: CAREER; Ligand; Engineering; Structure; Electronic

NON-TECHNICAL SUMMARYThe CAREER project supports computational materials science research and education aimed at understanding and designing electronic properties of materials, including electrical resistivity and optical behavior, by control over material structure at the level of atoms. The specific compounds of interest include oxides with transition metal cations, and focus on the effect that fluorine, which can substitute for oxygen in the materials, has on the electronic functionality. Previous research on transition metal oxides has established the importance of atomic structure engineering of electronic responses in many crystal families. Most conventional property-by-design routes rely, however, on changing the transition metal cation in oxides. This project seeks to apply another route - tuning the interactions in the crystal through anion (fluorine and oxygen) substitution. Changes in the geometry, arrangement and composition of the anion atoms will be explored through a confluence of materials theory techniques based on symmetry analyses, materials informatics (machine learning), and quantum mechanical calculations. The PI has ongoing collaborations with leading experts in synthesis and characterization of such materials composed of transition metals, oxygen, and fluorine; understanding derived here will stimulate experimental methods and vice versa. Continued investigation of known materials, while valuable, is inadequate to formulate strategies for deterministic property control. Knowledge obtained here will facilitate the selection and design of materials with tunable electronic states. It will benefit society by advancing the repertoire of structure-based design strategies to control electronic structure, which could lead to the discovery of new functional materials, e.g. for better performing energy storage and conversion systems, materials for transparent electronics, and optical technologies relying on laser generated light.This project will further the educational opportunities of students at Northwestern University and other academic institutions, precollege students, and contribute to the professional development of high school teachers. The PI will implement an educational plan to foster awareness, understanding, and appreciation of advanced technology materials and data-driven scientific methods through two main tasks. First, he will create Engineering Design Modules capable of engaging students in grades 9 through 12 by fostering model building skills to analyze and communicate concepts taught in secondary chemistry and physics courses that underpin many modern technologies, and support teachers preparing for the recently adopted Next Generation Science Standards. Second, he will create a Materials Informatics Curriculum to engage university students in modern informatics-based science problem-solving methods. All contextual learning activities will build knowledge, promote scientific and engineering literacy, and provide greater insight into the societal needs for engineering solutions, fostering cognitive skills through an emphasis on cause/effect relationships that are axiomatic to the research objectives and vital to the next-generation workforce. Assessment of the proposed educational activities and broad dissemination through multiple platforms will determine the efficacy of the educational activities, improve their implementation, and maximize impact.TECHNICAL SUMMARYThis CAREER award supports synergistic research, education, and outreach activities which focus on the design of functional electronic behavior in transition metal oxyfluorides using control over the ligand sublattice by oxygen/fluorine substitution and ordering. Conventional routes to direct the responses in transition metal oxides primarily rely on cation substitution and interfacial effects in thin films and superlattices, which offer limited control owing to a single (oxygen) anion - this makes materials discovery challenging. Remarkably, ligand (anion) engineering with mixed anion polyhedral building blocks remains to be fully exploited for property control and design, especially in these materials which already find use in energy generation and storage, phosphors, and catalysis. Combinations of applied group theory, informatics, and density functional theory calculations will be applied to achieve the main research objectives, which include (1) Advancing new theoretical methods to establish structure-function axioms for how anion order can be used to direct crystal structure and properties; (2) Formulating a quantitative theory of structure stability based on understanding the ligand sublattice symmetry and local bonding interactions; and (3) Understanding the consequences of mixed-anion polyhedral topologies on electronic properties. Structure-property axioms will be extracted by studying the consequences of anion substitution using oxyfluoride building blocks on physical properties in cryolite and elpasolite structures. With that knowledge, quantitative guidelines will be constructed to tailor electronic structure and properties in new oxyfluorides: metal-insulator transitions, electronic band gaps, and large non-linear optical responses. Success in this research will produce new knowledge underlying crystal stability, chemical bonding, and electronic behavior. It will articulate predictive rules for selecting new oxyfluorides, accelerate discovery, and enable an unprecedented expansion of compounds with varying electronic functions. Ultimately, interactions with experimental groups will lead to the discovery of functional properties in structurally and chemically more complex (hybrid) organic and inorganic materials than those proposed. Such collaborations will ensure that the virtual predictions translate into realistic models and new materials, which may transform the discovery process for materials deployed in glasses, phosphors, fuel-conversion, and Li-ion batteries technologies.This project will further the educational opportunities of students at Northwestern University and other academic institutions, precollege students, and contribute to the professional development of high school teachers. The PI will implement an educational plan to foster awareness, understanding, and appreciation of advanced technology materials and data-driven scientific methods through two main tasks. First, he will create Engineering Design Modules capable of engaging students in grades 9 through 12 by fostering model building skills to analyze and communicate concepts taught in secondary chemistry and physics courses that underpin many modern technologies, and support teachers preparing for the recently adopted Next Generation Science Standards. Second, he will create a Materials Informatics Curriculum to engage university students in modern informatics-based science problem-solving methods. All contextual learning activities will build knowledge, promote scientific and engineering literacy, and provide greater insight into the societal needs for engineering solutions, fostering cognitive skills through an emphasis on cause/effect relationships that are axiomatic to the research objectives and vital to the next-generation workforce. Assessment of the proposed educational activities and broad dissemination through multiple platforms will determine the efficacy of the educational activities, improve their implementation, and maximize impact.

CAREER项目支持计算材料科学研究和教育，旨在通过在原子水平上控制材料结构来理解和设计材料的电子特性，包括电阻率和光学行为。我们感兴趣的具体化合物包括带有过渡金属阳离子的氧化物，并重点研究了氟对材料中氧的替代作用对电子功能的影响。以往对过渡金属氧化物的研究表明，在许多晶体族中，电子响应的原子结构工程具有重要意义。然而，大多数传统的设计特性路线依赖于改变氧化物中的过渡金属阳离子。这个项目试图应用另一种途径——通过阴离子（氟和氧）取代来调节晶体中的相互作用。阴离子原子的几何、排列和组成的变化将通过基于对称分析、材料信息学（机器学习）和量子力学计算的材料理论技术的融合来探索。PI正在与由过渡金属、氧和氟组成的这类材料的合成和表征方面的主要专家进行合作；这里得到的理解将刺激实验方法，反之亦然。对已知材料的持续调查虽然有价值，但不足以制定确定性财产控制的战略。在这里获得的知识将有助于选择和设计具有可调谐电子态的材料。它将通过推进基于结构的设计策略来控制电子结构，从而使社会受益，这可能导致发现新的功能材料，例如用于性能更好的能量存储和转换系统，透明电子材料和依赖于激光产生光的光学技术。该项目将进一步增加西北大学和其他学术机构学生、大学预科学生的教育机会，并为高中教师的专业发展做出贡献。PI将通过两个主要任务，培养对先进技术材料和数据驱动科学方法的认识、理解和欣赏的教育计划。首先，他将创建工程设计模块，通过培养模型构建技能来吸引9至12年级的学生，以分析和交流中学化学和物理课程中教授的概念，这些概念是许多现代技术的基础，并支持教师为最近通过的下一代科学标准做准备。其次，他将创建一门材料信息学课程，让大学生学习基于现代信息学的科学问题解决方法。所有情境学习活动都将建立知识，促进科学和工程素养，并提供对工程解决方案的社会需求的更深入的了解，通过强调因果关系来培养认知技能，这些因果关系对于研究目标是不言自明的，对下一代劳动力至关重要。对建议的教育活动进行评估，并通过多个平台进行广泛传播，以确定教育活动的有效性，改善其实施，并最大限度地发挥影响。本职业奖支持协同研究、教育和推广活动，重点是通过氧/氟取代和有序控制配体亚晶格来设计过渡金属氟氧化物的功能电子行为。引导过渡金属氧化物反应的传统途径主要依赖于薄膜和超晶格中的阳离子取代和界面效应，由于单个（氧）阴离子的限制，它们提供有限的控制-这使得材料发现具有挑战性。值得注意的是，混合阴离子多面体构建块的配体（阴离子）工程在性能控制和设计方面仍有待充分利用，特别是在这些已经在能源产生和储存、荧光粉和催化方面得到应用的材料中。应用群论、信息学和密度泛函理论计算的结合将实现主要的研究目标，包括：(1)提出新的理论方法来建立结构-功能公理，以了解阴离子顺序如何用于指导晶体结构和性质；(2)在理解配体亚晶格对称性和局部键相互作用的基础上，建立了结构稳定性的定量理论；(3)了解混合阴离子多面体拓扑结构对电子性质的影响。结构-性质公理将通过研究使用氟氧基块的阴离子取代对冰晶石和斜冰晶石结构的物理性质的影响来提取。有了这些知识，将构建定量指南来定制新的氟氧化物的电子结构和性质：金属绝缘体跃迁，电子带隙和大型非线性光学响应。这项研究的成功将产生晶体稳定性、化学键和电子行为的新知识。它将阐明选择新的氟氧化物的预测规则，加速发现，并使具有不同电子功能的化合物得到前所未有的扩展。最终，与实验组的相互作用将导致在结构和化学上更复杂的有机和无机材料的功能特性的发现。这样的合作将确保虚拟预测转化为现实模型和新材料，这可能会改变玻璃，荧光粉，燃料转换和锂离子电池技术中部署的材料的发现过程。该项目将进一步增加西北大学和其他学术机构学生、大学预科学生的教育机会，并为高中教师的专业发展做出贡献。PI将通过两个主要任务，培养对先进技术材料和数据驱动科学方法的认识、理解和欣赏的教育计划。首先，他将创建工程设计模块，通过培养模型构建技能来吸引9至12年级的学生，以分析和交流中学化学和物理课程中教授的概念，这些概念是许多现代技术的基础，并支持教师为最近通过的下一代科学标准做准备。其次，他将创建一门材料信息学课程，让大学生学习基于现代信息学的科学问题解决方法。所有情境学习活动都将建立知识，促进科学和工程素养，并提供对工程解决方案的社会需求的更深入的了解，通过强调因果关系来培养认知技能，这些因果关系对于研究目标是不言自明的，对下一代劳动力至关重要。对建议的教育活动进行评估，并通过多个平台进行广泛传播，以确定教育活动的有效性，改善其实施，并最大限度地发挥影响。