CAREER: Semiconductor Clusters: Chemistry at the Interface of Small Molecules and Quantum Dots

这项由大分子、超分子和纳米化学（MSN）计划颁发的职业奖支持了哥伦比亚大学的Jonathan Owen教授的工作，该大学致力于了解纳米晶体半导体的成核和生长及其与前体分子转化的关系。拟议工作的核心重点包括两个部分：（一）前体转化的动力学和机制及其与团簇结晶的关系，以及它们随后转化为更大的纳米晶体，无论是通过组装还是原子接原子的生长过程;（二）通过对簇配位的系统剪裁来表征和修饰这些材料中引起表面态发光的表面结构特征化学.通过研究原子级精确的簇，负责捕获激子的特定结构元素的分配和晶体生长机制的研究都成为可能，其细节程度使用传统材料和方法是不可能的。这一建议的更广泛的影响在于它的重要性，表面张力和胶体晶体的成核的经典模型。理解簇稳定性的起源将澄清簇如何不同于较大的纳米晶体，其中根据吉布斯-汤普森关系，稳定性随颗粒尺寸增加。这种差异具有重要的后果，为结晶形核和生长机制，并在鲜明的对比，以支持经典的成核理论的自由能参数。结构功能关系的研究被整合到K-8课程中，该课程教授分子结构对日常生活有形方面的重要性。通过将这一背景融入科学概念的教学，化学结构与年轻学生相关，促进了对科学思维的广泛兴趣。

This CAREER award by the Macromolecular, Supramolecular, and Nanochemistry (MSN) program supports work by Professor Jonathan Owen at Columbia University - endowed to understand the nucleation and growth of nanocrystalline semiconductors and their relationship to the conversion of precursor molecules. The core focus of the proposed work consists of two parts: (i) The kinetics and mechanisms of precursor conversion and their relationship to the crystallization of clusters and their subsequent conversion into larger nanocrystals, whether by assembly or atom-by-atom growth processes; (ii) To characterize and modify the surface structural features that cause surface state luminescence in these materials by systematic tailoring of cluster coordination chemistry. By studying atomically precise clusters, the assignment of specific structural elements responsible for trapping of excitons and investigations of crystal growth mechanisms all become possible with a level of detail not possible using traditional materials and methods. The broader impact of this proposal rests in its importance to classical models of surface tension and the nucleation of colloidal crystals. Understanding the origins of cluster stability will clarify how clusters are distinct from larger nanocrystals where the stability increases with the particles dimensions according to the Gibbs-Thompson relationship. This difference has important consequences for nanocrystal nucleation and growth mechanisms and is in stark contrast to the free energy arguments that underpin classical nucleation theory. The study of structure function relationships is integrated into a K-8 curriculum that teaches the importance of molecular structure to tangible aspects of everyday life. By integrating this context into the teaching of scientific concepts, chemical structure is made relevant to young students, promoting broad interest in scientific thinking.