Design and Preparation of Organic-Metal Halide Hybrids Exhibiting Charge Transfer

在过去的十年里，基于含有有机和无机成分的混合材料的太阳能电池表现出了迅速提高的性能，现在已经达到了与商业硅板竞争的水平。通过这个由美国国家科学基金会固态和材料化学项目支持的项目，南加州大学的研究团队对这些材料性能如此出色的原因有了更深入的了解，并研究了在未来推动这些混合材料性能更高的策略。这项工作是高度跨学科的，结合了有机合成、计算化学和物理性质测量的努力，以研究光如何与这些复杂材料相互作用。该项目还招募了附近喜瑞都社区学院的本科生（其中54%是拉丁裔，8%是非裔美国人）和美国本土高中生参与研究。该项目由美国国家科学基金会固态和材料化学项目支持，加深了我们对有机分子在激发态中如何在周期性无机结构中相互作用的基本理解。在以前的研究中，有机成分在性质上主要是结构性的，不积极参与价带或导带。在这个项目中，南加州大学的研究团队将重点放在有机成分是有源光学或电子元件的材料上，通过使其成为杂化固体的价带和/或导带的主要贡献者。主要研究人员开发了新的材料设计原则，以促进光激发载流子通过固态的增强电荷输运。在此过程中，对如何将有机染料的最高占据轨道（HOMO）和最低未占据轨道（LUMO）与扩展框架的导电带或价带对齐有了新的认识。在本研究中开发的材料作为模型系统来研究有机分子上的局部激子如何转移到晶体金属卤化物区域的非局部带中。系统的研究包括材料设计、合成、密度泛函理论计算和物理性质测量的结合，以回答关于晶体结构中有机和无机成分如何相互作用的基本问题。此外，该项目还招募了附近喜瑞都社区学院的本科生（其中54%是拉丁裔，8%是非裔美国人）和美国本土高中生参与研究。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。

PART 1: NON-TECHNICAL SUMMARY In the last ten years, solar cells based on hybrid materials that contain organic and inorganic components have exhibited rapidly improving performance that has now reached levels competitive with commercial silicon panels. Through this project, which is supported by the Solid State and Materials Chemistry program at NSF, the research team at the University of Southern California develops a deeper understanding of why these materials perform so exceptionally well and investigates strategies to push the performance of these hybrid materials even higher in the future. The work is highly interdisciplinary, combining efforts in organic synthesis, computational chemistry, and physical property measurements to examine how light interacts with these complex materials. The project also engages undergraduates from the nearby Cerritos Community College (which is 54% Latino, 8% African American) and Native American High School students in the research. PART 2: TECHNICAL SUMMARYThis project, which is supported by the Solid State and Materials Chemistry program at NSF, deepens our fundamental understanding of how organic molecules in their excited state interact within periodic inorganic structures. In previous studies the organic component has been predominantly structural in nature, not actively participating in the valence or conduction bands. In this project the research team at the University of Southern California focuses on materials where the organic component is an active optical or electronic element, by making it a major contributor to the valance and/or conduction bands of the hybrid solid. The principle investigators develop new material design principles to promote enhanced charge transport of photoexcited carriers through the solid state. In the process, new understanding is achieved about how to align the highest occupied (HOMO) and lowest unoccupied molecular orbitals (LUMO) of organic dyes with the conduction or valence bands of the extended framework. The materials that are developed during this study act as model systems to investigate how localized excitons on the organic molecules can be transferred into the far more delocalized bands of the metal halide region of the crystal. The systematic investigation involves a combination of materials design, synthesis, Density Functional Theory calculations, and physical property measurement to answer fundamental questions about how the organic and inorganic components interact within the crystal structure. Additionally, the project engages undergraduates from the nearby Cerritos Community College (which is 54% Latino, 8% African American) and Native American High School students in the research.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.