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

在这个由化学系高分子、超分子和纳米化学计划资助的项目中，罗切斯特大学的托德·克劳斯教授正在研究被称为胶体半导体纳米晶(NCS)的微小无机颗粒。由于其大小相关的特性，这些NC有可能影响许多活跃的研究和技术领域。然而，缺乏合理的综合机构阻碍了NC设计和应用的进步。该项目研究低温NC合成的新基本策略，这些策略可能可扩展到工业规模，从而与当前的化学制造程序兼容。大规模合成半导体纳米碳管，特别是那些毒性较低的纳米碳管，可能会在生物、医学、光学和光子学等领域开发新的应用。该项目提供两名研究生和一名本科生的教育和培训。这两名研究生还通过与罗切斯特博物馆和科学中心的互动来组织和指导外展工作。胶体半导体NCS领域的一个长期而重大的挑战是在基础水平上了解NCS是如何合成的，并利用这些知识以合理的方式制造改进的NCS。本项目的总体目标是在合成具有更好的化学或光物理性能的NC的过程中，对NC的合成机理有一个更详细的了解。利用光学、质量和核磁共振光谱进行了几个实验，以获得对感兴趣的NCS的化学反应机理的更完整的了解。还确定了掺杂半导体纳米管的电荷、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一大类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.