CAREER: Spectroscopic Imaging of Nanoscale Structure and Chemistry at Soft-Hard Interfaces

该项目由材料研究部固态和材料化学项目支持，结合了电子显微镜及其在软硬界面表征中的应用的研究、教育和推广。了解软硬界面的结构和化学是材料科学、化学和医学领域的一个关键挑战。表面原子代表了每个纳米晶体的很大一部分，这使得它们的表面化学性质具有决定性。本项目旨在利用最新一代的扫描透射电子显微镜，结合制备纳米颗粒的新方法，开发纳米颗粒表面分子排列的可视化方法，用于高分辨率成像。总之，这些技术将使研究能够测量分子分布的密度和均匀性如何与金属纳米颗粒表面的特性相关，包括其局部组成、晶体取向和几何形状。所获得的见解将加速下一代技术的设计和开发，包括微创癌症治疗、高效光伏和医疗显像剂。除了上述研究之外，该项目还包括一项教育和推广计划，旨在将尖端电子显微镜的范围扩大到下一代科学家和工程师。电子显微镜正在成为一种广泛使用的跨学科工具，用于在原子尺度上表征材料的组成。该项目包括电子显微镜的推广、教学和培训，涵盖K-12年级、本科生和研究生。这些努力包括：通过电子显微镜和纳米科学的展览吸引公众，通过高通量、主动的用户培训学习方法来加强国家研究基础设施，以及为研究生和本科生重新设计电子显微镜课程。这些努力还支持了一个多样化的、国家认可的用户设施，并对每年培训100多名电子显微镜理论和实践的新用户产生了直接影响。该项目由材料研究部固态和材料化学项目支持，旨在利用电子显微镜和光谱学对胶体纳米颗粒软硬界面的表面化学有一个基本的了解。实验将通过增加电子显微镜产生的定量信息的规模，然后挖掘结果数据集来研究单个纳米颗粒内部和之间的表面化学趋势和统计分布，从而产生新的见解。一个特别的焦点将是理解纳米颗粒表面分子的不均匀和各向异性分布的起源。这项工作将使直接测试和完善分子包装的理论模型成为可能，并为如何在纳米尺度上定制分子涂层提供见解。该项目包括电子显微镜的推广、教学和培训，涵盖K-12年级、本科生和研究生。这些努力包括：通过电子显微镜和纳米科学的展览吸引公众，通过高通量、主动的用户培训学习方法来加强国家研究基础设施，以及为研究生和本科生重新设计电子显微镜课程。该项目的教育和推广计划将利用最新可用的开源软件进行图像模拟、数据处理和远程操作，以扩大跨学科前沿分析电子显微镜的范围。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。

NON-TECHNICAL SUMMARY This NSF CAREER award project, supported by the Solid State and Materials Chemistry program in the Division of Materials Research, combines research, education, and outreach in electron microscopy and its application to characterizing soft-hard interfaces. Understanding the structure and chemistry at soft-hard interfaces is a key challenge across materials science, chemistry, and medicine. Surface atoms represent a large fraction of each nanocrystal, making their surface chemistry a defining property. This project aims to develop methods to visualize the arrangement of molecules on the surfaces of nanoparticles by using the latest generation of scanning transmission electron microscopes in combination with new methods to prepare nanoparticles for high resolution imaging. Together, these techniques will enable studies that measure how the density and uniformity of molecular distributions are related to properties of the metal nanoparticle surface, including its local composition, crystal orientation, and geometry. The insights gained will speed the design and development of next-generation technologies including minimally-invasive cancer therapies, high-efficiency photovoltaics, and medical imaging agents.In addition to the research described above, this project includes an education and outreach plan that aims to broaden the reach of cutting-edge electron microscopy to the next generation of scientists and engineers. Electron microscopes are becoming a widespread, cross-disciplinary tool for characterizing the composition of materials on the scale of atoms. This project includes outreach, teaching, and training in electron microscopy spanning K-12, undergraduate, and graduate students. These efforts include: engaging the public through exhibits on electron microscopy and nanoscience, enhancing the national research infrastructure via high-throughput, active learning methods for user training, and redesigning an electron microscopy course for graduate and undergraduate students. These efforts also support a diverse, nationally-recognized user facility and have direct impact in training over 100 new users in the theory and practice of electron microscopy each year. TECHNICAL SUMMARY This NSF CAREER award project, supported by the Solid State and Materials Chemistry program in the Division of Materials Research, aims to produce a fundamental understanding of the surface chemistry at soft-hard interfaces of colloidal nanoparticles using electron microscopy and spectroscopy. Experiments will generate new insights by increasing the scale of quantitative information generated through electron microscopy, and then mining the resulting datasets to study trends and statistical distributions in surface chemistry that occur within and between individual nanoparticles. A particular focus will be understanding the origins of inhomogeneous and anisotropic distributions of molecules on nanoparticle surfaces. This work will make it possible to directly test and refine theoretical models of molecular packing and provide insight into how molecular coatings can be tailored on the nanoscale. This project includes outreach, teaching, and training in electron microscopy spanning K-12, undergraduate, and graduate students. These efforts include: engaging the public through exhibits on electron microscopy and nanoscience, enhancing the national research infrastructure via high-throughput, active learning methods for user training, and redesigning an electron microscopy course for graduate and undergraduate students. The project's education and outreach plan will utilize newly available open-source software for image simulation, data processing, and remote operation in order to broaden the reach of cutting-edge analytical electron microscopy across disciplines.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.