Synthesis, Synthetic Mechanism, and Single Particle Microscopy of Colloidal Semiconductor Nanocrystals

在这个由化学学部大分子、超分子和纳米化学项目资助的项目中，罗切斯特大学的Todd Krauss教授正在研究被称为胶体半导体纳米晶体（NCs）的微小无机颗粒。由于它们的尺寸依赖性，这些nc具有影响许多活跃研究和技术领域的潜力。然而，缺乏合理的合成机制阻碍了数控设计和应用的进步。该项目研究了低温数控合成的新基本策略，这些策略有可能扩展到工业规模，因此与当前的化学制造程序兼容。大规模合成半导体纳米材料，特别是那些具有低毒性的纳米材料，可能会在生物学和医学、光学和光子学方面发展新的应用。本项目提供两名研究生和一名本科生的教育和培训。这两位研究生还通过与罗切斯特博物馆和科学中心的对接，组织和指导外联工作。胶体半导体NCs领域长期存在的重大挑战是在基本层面上理解NCs是如何合成的，并利用这些知识以合理的方式改进NCs。该项目的总体目标是对NC合成机制有更详细的了解，从而合成具有改进化学或光物理性质的NC。利用光学、质量和核磁共振波谱进行了几次实验，以更全面地了解感兴趣的nc的化学反应机理。此外，还确定了掺杂半导体nc的电荷、光致发光和杂质原子浓度之间的重要关系。这些研究将有助于理解各种纳米结构材料中无法解释的光物理现象。

In this project funded by the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Professor Todd Krauss of the University of Rochester is studying tiny inorganic particles called colloidal semiconductor nanocrystals (NCs). These NCs have the potential to impact numerous areas of active research and technology due to their size-dependent properties. However, the lack of a rational synthetic mechanism has impeded advances in NC design and applications. This project investigates new fundamental strategies for low-temperature NC syntheses that are potentially scalable to industrial volumes, and thus are compatible with current chemical manufacturing procedures. Large-scale synthesis of semiconductor NCs, especially those with reduced toxicity, may enable the development of new applications in biology and medicine, optics and photonics. This project provides for the education and training of two graduate students and one undergraduate student. The two graduate students also organize and direct outreach efforts through interfacing with the Rochester Museum and Science Center. A long-standing and significant challenge in the field of colloidal semiconductor NCs is to understand at a fundamental level how NCs are synthesized, and to use this knowledge to make improved NCs in a rational manner. The overall goal in this project is to develop a more detailed understanding of NC synthesis mechanisms in route to synthesizing NCs with improved chemical or photophysical properties. Several experiments are conducted utilizing optical, mass and nuclear magnetic resonance spectroscopies to obtain more complete understanding of the chemical reaction mechanism for the NCs of interest. Also, the important relationship between charge, photoluminescence and impurity atom concentration for doped semiconductor NCs are being determined. These studies will aid in the understanding of unexplained photophysical phenomena in a wide class of nanostructured materials.