RUI: The Vibrational Structure of Atomically-Precise Nanostructures: From Molecular Clusters to Quantum Dots

在这个由化学系高分子、超分子和纳米化学计划支持的合作项目中，巴纳德学院的Andrew Crowther教授、哥伦比亚大学的Jonathan Owen教授和他们的本科生团队正在发展对原子精密量子点纳米结构的振动结构的理解。分子和材料中原子的振动是与化学键的伸展和收缩有关的一种基本类型的原子运动。通过了解分子振动以及这些运动如何影响结构和几何形状，科学家可以改进材料和设备的性能。本论文主要研究了硒化镉和硫化镉量子点的设计、合成和表征。这些材料被用作许多消费品中的光致抗蚀剂，如相机测光仪、闹钟收音机、警报设备和太阳能路灯。与巴纳德学院的项目、高等教育机会计划和大学科技入学计划建立合作伙伴关系，让低收入和代表性不足的大学和K-12学生参与研究。每年夏天，一个未被充分代表的学生会跟踪一个正在进行这个项目的研究生，加入实验室进行他们自己的研究。这项研究也被纳入了巴纳德学院一年一度的新的“纳米日”活动，让当地高需求学校的学生和教师接触纳米科学和材料化学。在这个项目中，拉曼光谱被用来确定一组不同的，但又相互关联的原子精确的团簇和量子点的振动结构。配体和金属阳离子交换反应探索了表面化学如何影响一系列大小和形状精确的硫化镉和硒镉量子点的振动结构。核壳量子点在尺寸和界面原子分布上具有单分散性，使得研究核、壳和界面的振动结构成为可能。最后，分子簇被连接起来形成二聚体、三聚体，并最终形成长的聚合物链，以确定振动结构如何从零维变化到一维极限。每年夏天，一个未被充分代表的学生在这个项目上跟踪一个当前的研究生，然后加入实验室进行他们自己的研究。这项研究还被纳入巴纳德学院一年一度的新的“纳米日”活动，让来自当地高需求学校的学生和教师接触到微观层面的物理化学系统、纳米科学以及它们的材料性质的研究。这些都是新科技发展的关键领域，新科技将推动美国未来的创新。

In this collaborative project, supported by the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Professor Andrew Crowther of Barnard College, Professor Jonathan Owen of Columbia University, and a team of their undergraduate research students are developing an understanding of the vibrational structure of atomically precise quantum dot nanostructures. The vibrations of atoms in molecules and materials are a fundamental type of atomic motion related to the stretching and contracting of chemical bonds. By understanding molecular vibrations and how these motions impact structure and geometry, scientists can improve the performance of materials and the devices. This research is focused on the design, synthesis and characterization of quantum dots of cadmium selenide and cadmium sulfide. These materials are used as photoresists in many consumer items such as camera light meters, clock radios, alarm devices, and solar street lights. Partnerships with programs at Barnard College, the Higher Education Opportunity Program and Collegiate Science and Technology Entry Program, to involve low-income and underrepresented college and K-12 students to research. Each summer an underrepresented student shadows a current research student on this project, joining the laboratory to conduct their own research. This research is also incorporated into a new, annual "NanoDay" at Barnard College that exposes students and teachers from local high-need schools to nanoscience and materials chemistry. In this project Raman spectroscopy is used to determine the vibrational structure of a diverse, yet related set of atomically precise clusters and quantum dots. Ligand and metal cation exchange reactions probe how surface chemistry affects the vibrational structure of a series of qadmium selenide and cadmium sulfide quantum dots of precise size and shape. Core-shell quantum dots with monodispersity in size and interfacial atomic distributions enable investigations of the core, shell, and interfacial vibrational structure. Finally, molecular clusters are linked to form dimers, trimers, and ultimately long polymer chains to determine how the vibrational structure changes from the zero-dimensional to the one-dimensional limit. Each summer an underrepresented student shadows a current research student on this project and subsequently joins the laboratory to conduct their own research. This research is also incorporated into a new, annual "NanoDay" at Barnard College that exposes students and teachers from local high-need schools to the study of physical and chemical systems at the microscopic level, nanoscience, as well as their material properties. These are key areas in the development of new science and technology, which will power American innovation in the future.