CAREER: Towards a Paradigm of Molecular-Level Control of Solid-State Chemistry

本项目将寻求创新的方法来设计和合成新材料；具有新特性的无机固体的发现可以为各种社会挑战带来解决方案。材料设计的范例将有助于改变我们创造和使用新材料的方式。人们可以预测，然后创造出一种原子结构，从而产生期望的特性。然而，这种有针对性的功能材料设计仍然是一项艰巨的任务。该项目将通过理解和修改材料化学形成的途径来研究合成科学。这项基础研究具有发现新的化学转化的额外潜力，可以用于有效的能量转换和储存。材料化学教育是培养科学、技术、工程和数学（STEM）技能劳动力的重要组成部分。然而，普通化学教育往往以分子结构为中心。该项目将创建STEM教育工具包，让K-12学生学习材料化学，同时与K-12州科学标准保持一致。外展活动将与“职前教师研究经验”项目合作，以改进工具包的实施，并为教师提供科学研究经验。与有机分子的合成相反，合理设计生成扩展无机材料的化学反应仍然是一个长期存在的问题。这个CAREER项目提供了一个系统的方法来解决这个问题，并试图通过理解和改变分子水平上的合成途径来创造亚稳的无机氧化物、硫族化合物和肽。该项目主要研究固态复分解反应是如何发生的，并努力发明有选择地改变其途径的方法。固态化学反应通常受到固态扩散的限制，这就排除了在固态化学中产生动力学控制所需的选择性断键/成键的任何概念。该项目利用小分子来规避固态反应中的扩散速率限制步骤，解决了这一挑战。利用原位x射线和中子散射方法，包括总散射和对分布函数分析，可以进行基本的机理研究。在这项研究中获得的知识有可能发现新的和亚稳态的功能材料，无论是具有低缺陷浓度的太阳能电池，能够进行可逆修饰的电池电极，还是分层结构的催化剂和宿主。通过创建K-12 STEM教育工具包以及职前教师积极参与功能材料的发现和合成，这些努力与教育紧密结合。

Non-Technical AbstractThis project will pursue innovative approaches to design and synthesize new materials; the discovery of inorganic solids with novel properties can bring solutions to various societal challenges. A paradigm of materials design would serve to transform the way in which we create and use novel materials. One could predict, and then create, an atomistic structure that gives rise to the desired properties. However, this targeted design of functional materials remains to be a difficult task. This project will study the science of synthesis by understanding and modifying the pathways through which materials are formed chemically. This fundamental research has the additional potential to discover new chemical transformations that can be exploited for efficient energy conversion and storage. Materials chemistry education is an important ingredient for a Science, Technology, Engineering, and Mathematics (STEM) skilled workforce. However, general chemical education often centers on molecular structures. This project will create STEM education kits that engage K-12 students with materials chemistry while aligning with K-12 State Science Standards. The outreach activities will be partnered with a Research Experience for Preservice Teachers program to improve the kit implementation and to provide teachers with experience in scientific research.Technical AbstractIn contrast to the synthesis of organic molecules, the rational design of chemical reactions that yield extended inorganic materials remains a long-standing problem. This CAREER project provides a systematic approach to this problem and seeks to create metastable inorganic oxides, chalcogenides and pnictides by understanding and altering synthesis pathways at the molecular level. The project primarily studies how solid-state metathesis reactions take place and strives to invent approaches to selectively alter their pathways. Solid-state chemical reactions are often limited by solid-state diffusion, which precludes any notion of selective bond breaking/making as needed to engender kinetic control in solid-state chemistry. This project approaches this challenge using small molecules to circumvent diffusion rate-limiting steps in solid-state reactions. The fundamental mechanistic studies are enabled using in situ X-ray and neutron scattering methods, including total scattering and pair distribution function analysis. The knowledge that will be gained in this research has potential to discover new and metastable functional materials, be it solar cells with low defect concentrations, battery electrodes that enable reversible modification, or hierarchically-structured catalysts and hosts. These efforts are closely integrated with education through the creation of K-12 STEM education kits and the active participation of pre-service teachers in the discovery and synthesis of functional materials.