CAREER: Theory-Guided Design of Porous Organic Frameworks for Energy Conversion and Storage

该职业奖支持计算和理论研究，以开发和应用专门的计算机模拟，以了解电子和能量如何在一类被称为共价有机框架的材料中转移。这些材料在单分子尺度上是多孔的，使它们成为气体储存和分离技术的有力候选者；初步工作表明，它们也可能为可再生能源的收集和转化提供有价值的支架。例如，这些分子框架可用于固定和定向材料的吸光部分，以实现有效的能量转移或增加能量存储密度。该项目将通过提供有针对性的计算机模拟策略来预测这些材料中电子在吸收可见光后的行为，从而加速这类有前途的可再生能源应用材料的发展。PI在模拟的开发和应用方面指导一个由本科生和硕士生组成的研究团队。他们的跨学科培训将有助于为物理和计算科学领域的强大STEM劳动力做好准备。这项研究的目标也直接与PI作为教育工作者的努力相结合，以提高大学生和高中生的能源素养。将与学生研究人员合作开发说明在这里研究的材料中发挥作用的能量转换机制的教育模拟；在PI的能源、材料和化学教室工作；并与公众分享，以扩大获得能源科学资源的途径。这些研究和教育目标与世界海洋大学的PI最近建立的由本科生推动的能源知识普及计划直接相关，该计划将通过发展成为服务学习计划而进一步得到加强。该职业奖支持共价有机框架的光学和电子性质的计算和理论研究。由于缺乏将这些框架的光学和电子特性与其底层结构联系起来的扩展长度和时间尺度的预测模型，阻碍了光活性和电活性共价有机框架的合理设计。该项目旨在通过开发一种多参考计算方法来解决这一知识差距，该方法战略性地将半经验基态和激发态电子结构计算联系起来，以预测电活性和光活性共价有机框架中的光物理性质、能量转移和载流子迁移率。该方法建立在PI对密度功能紧密结合的低洼激发态的时间无关方法的实现之上，以结合这些材料中的电荷转移激发以及电子状态之间的耦合。这种基于约束密度功能紧密结合的构型相互作用（CDFTB-CI）方法将用于研究选定的共价有机框架作为单线态裂变材料和光开关储能材料中的光激发和电子/能量转移。这里开发和应用的模型也将为计算材料科学家提供部分蓝图，以量化其他拓扑复杂环境（如金属有机框架）中结构和电子特性之间的联系。该项目将直接培训和指导一所主要本科院校的15-20名本科生和硕士研究生。为了扩大这项工作的教育影响，并向公众传播能量转换和存储概念，PI将创建和评估增强材料模拟的有效性，以支持能量转换的数学和物理模型的流畅性。该项目还将为PI的能源大使计划建立可持续发展的轨迹，该计划将能源科学、工程、经济、政策和商业领域的本科生研究与跨学科沟通技能培养和K-12外展结合起来。材料研究部和化学部为该奖项提供资金。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。

NONTECHNICAL SUMMARYThis CAREER award supports computational and theoretical research to develop and apply specialized computer simulations to understand how electrons and energy are transferred within a class of materials known as covalent organic frameworks. These materials can be porous at the scale of single molecules, making them strong candidates for the storage of gasses and for separation technologies; preliminary work suggests that they may also provide a valuable scaffold for applications in renewable energy harvesting and conversion. For example, these frameworks of molecules may be used to anchor and orient the light-absorbing parts of a material for efficient energy transfer or increased energy storage density. This project will accelerate the development of this promising class of materials for renewable energy applications by providing a targeted computer simulation strategy to predict the behavior of electrons in these materials after they absorb visible light.The PI mentors a team of undergraduate and Master's student researchers in the development and application of simulations. Their cross-disciplinary training will contribute to the preparation of a robust STEM workforce in the physical and computational sciences. The goals of this research also directly integrate with the PI's efforts as an educator to enhance energy literacy among undergraduate and high school students. Educational simulations that illustrate the energy conversion mechanisms at play in the materials studied here will be developed in collaboration with student researchers; employed in the PI's energy, materials, and chemistry classrooms; and shared with the public to broaden access to energy science resources. These research and educational objectives are directly linked to an undergraduate student-driven energy literacy outreach initiative, recently established by the PI at WWU, which will be further enhanced through development into a service learning program.TECHNICAL SUMMARYThis CAREER award supports computational and theoretical research on optical and electronic properties of covalent organic frameworks. The rational design of photoactive and electroactive covalent organic frameworks is hindered by a lack of predictive models at extended length and time scales to link the optical and electronic properties of these frameworks to their underlying structure. This project aims to address this knowledge gap through the development of a multireference computational approach that strategically links semiempirical ground- and excited-state electronic structure calculations to predict photophysical properties, energy transfer, and charge carrier mobility in electroactive and photoactive covalent organic frameworks. The approach builds on the PI's implementation of a time-independent approach to low-lying excited states in density-functional tight-binding to incorporate charge-transfer excitations as well as couplings between electronic states in these materials. This constrained density-functional tight-binding based configuration interaction (CDFTB-CI) approach will be deployed to study photoexcitation and electron/energy transfer in selected covalent organic frameworks as singlet fission materials and as photoswitchable energy storage materials. The models developed and applied here will also provide a partial blueprint for computational materials scientists to quantify links between structural and electronic properties in other topologically complex environments such as metal-organic frameworks.This project will directly enable the training and mentoring of a diverse group of 15-20 undergraduate and masters-level research students at a primarily undergraduate institution. To broaden the educational impact of this work and to communicate energy conversion and storage concepts to the public, the PI will create and assess the effectiveness of augmented materials simulations that support fluency in mathematical and physical models of energy conversion. This project will also establish a sustainable trajectory for the PI's Energy Ambassadors initiative, a program that couples undergraduate research across the science, engineering, economics, policy, and business of energy with cross-disciplinary communication skill-building and K-12 outreach.The Division of Materials Research and the Division of Chemistry contribute funds to this award.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.