CAREER: Tunable Metal Oxide Materials via Coordination Assembly of Molecular Clusters

非技术综述：固态金属氧化物是一类对当前和新兴技术至关重要的材料。然而，由于缺乏对单个原子位置的精确控制，使这些材料具有目标和可预测的性质仍然是一个挑战。在材料研究部固态和材料化学项目的支持下，Schimpf教授使用预成型分子积木的组装作为一种方法，以获得定义明确、成分广泛可调和精确定制的金属氧化物。这项研究包括合成材料、测量性能和设计假设的迭代循环，以了解在这些分子组装的金属氧化物中观察到的结构-性能关系。这些研究使人们对以下因素有了新的理解：(1)控制从预成型的积木块合成具有不同或复杂组成的金属氧化物的能力；(2)决定所得到的固态材料的性质。该项目还为社区大学生提供了一个平台，让他们在设计和学习与能源相关的材料方面获得研究经验。加州大学圣地亚哥分校的研究人员与圣地亚哥地区为拉美裔服务的社区大学的教职员工合作，为这些机构的学生设计项目并提供指导。这些努力的目标是吸引学生从事科学、技术、工程和数学(STEM)的职业，并为他们在这一职业道路上的未来发展做好准备。技术概述：该项目由材料研究部的固态和材料化学计划支持，使用分子金属氧化物簇合物的配位组装，以促进获得具有不同组成和定制性能的广泛可调的新型金属氧化物材料。与统计掺杂半导体不同，基于分子的材料提供了获得复杂的金属氧化物化合物的途径，这些化合物具有精确的原子位置，从而能够进行仔细的结构性能评估。研究人员使用迭代过程来设计和了解由多金属氧酸盐(POM)阴离子与金属阳离子桥联的簇状金属氧化物骨架的模块化性质。该过程允许评估哪些金属和团簇特征在规定金属氧化物骨架的组装和所得到的性质方面是重要的。考察的因素包括金属电荷、氧化态、硬/软酸和团簇电荷、尺寸和稳定性。通过合作，理论建模支持对观察到的结构-性能趋势的解释，并由此对合理的材料设计原则进行预测。这项研究的结果有望为具有目标性质的分子基金属氧化物的合理设计提供指导。该项目也为社区学院学生提供研究经验奠定了基础。圣地亚哥地区的社区学院为来自弱势种族、民族或经济群体的大部分学生提供服务，从而提供机会让我们人口中人数较少的一部分参与科学、技术、工程和数学(STEM)研究和培训。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical summary: Solid-state metal oxides are a class of materials vital to current and emerging technologies. Making these materials with targeted and predictable properties, however, remains a challenge due to the lack of precise control over individual atom location. In this project, supported by the Solid State and Materials Chemistry Program in the Division of Materials Research, Prof. Schimpf uses the assembly of pre-formed molecular building-blocks as a route to metal oxides with well-defined, broadly tunable compositions and precisely tailored properties. This research consists of an iterative cycle of synthesizing materials, measuring properties and designing hypotheses to understand the structure-property relationships observed in these molecular-assembled metal oxides. The studies lead to new understanding of the factors that (1) govern the ability to synthesize metal oxides with diverse or complex compositions from pre-formed building-blocks and (2) dictate the properties of the resulting solid-state materials. This project also provides a platform for community college students to gain research experience designing and studying energy-relevant materials. The UC San Diego-based researchers work with faculty at Hispanic serving community colleges in the San Diego area to design projects for and mentor students at these institutions. The goals of these efforts are to attract students to careers in science, technology, engineering and mathematics (STEM) and to prepare them for future steps along this career path. Technical summary: This project, supported by the Solid State and Materials Chemistry Program in the Division of Materials Research, uses the coordination assembly of molecular metal oxide clusters to facilitate access to new and widely tunable metal oxide materials with diverse compositions and tailored properties. Unlike statistically doped semiconductors, molecule-based materials offer access to complex metal oxide compositions with precisely known atom positions, enabling careful structure-property evaluations. The researchers employ an iterative process to design and understand the modular properties of cluster-based metal oxide frameworks consisting of polyoxometalate (POM) anions bridged with metal cations. This process allows evaluation of which metal and cluster characteristics are important in dictating the assembly and resulting properties of metal oxide frameworks. Factors that are investigated include metal charge, oxidation state and hard/soft acidity and cluster charge, size and stability. Through a collaboration, theoretical modeling supports explanations of observed structure-property trends and resulting predictions for rational materials design principles. Results from this research are anticipated to provide guidelines for the rational design of molecule-based metal oxides with targeted properties. This project also forms the foundation to provide research experiences for community college students. Community colleges in the San Diego area serve a large percentage of students from disadvantaged racial, ethnic or economic groups, and thus offer an opportunity to engage an underrepresented part of our population in science, technology, engineering and mathematics (STEM) research and training.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.