Enabling Next Generation Quantum Dot Emitters via Correlated Photophysics and Atomic Structure

通过这一奖项，化学系的高分子、超分子和纳米化学项目将资助范德比尔特大学的桑德拉·罗森塔尔教授和詹姆斯·麦克布莱德教授加快亚微观半导体晶体或量子点的开发。这些结构发光，并被用于各种应用，例如固态照明和显示器，以及用于显微镜分析的生物结构的标记。PI已经开发了一种新的表征方法来确定量子点的光发射效率如何与其原子结构相关联。最终目标是优化不使用有毒铅和镉的量子点系统的光发射。作为这项工作的一部分，正在通过本科生研究机会和面向农村中学生的推广活动向下一代科学家介绍不断增长的纳米技术领域。拟议的工作是合成无镉的胶体核/壳纳米晶体，并使用飞秒荧光上转换光谱表征它们的整体载流子动力学。同时，通过将单个纳米晶体水平的荧光动力学与相同粒子的原子结构和化学成分相关联，使用高分辨率高角环形暗场扫描透射电子显微镜(HAADF-STEM)和使用Vanderbilt的Tecnai Osiris的能量色散光谱图(STEM-EDS)来确定性能最佳的结构。通过系综载流子动力学和相关性研究获得的信息为改进当前的合成方法提供了目标。

With this award, the Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division is funding Professors Sandra Rosenthal and James McBride at Vanderbilt University to accelerate the development of sub-microscopic crystals of semiconductors, or quantum dots. These structures emit light and are used in diverse applications such as solid state lighting and displays and labeling of biological structures for analysis using microscopy. The PIs have developed a new characterization method to determine how the efficiency of light emission from a quantum dot is correlated to its atomic structure. The ultimate goal is to optimize the light emission of quantum dot systems that do not utilize toxic lead and cadmium. As a part of this effort, the growing field of nanotechnology is being introduced to the next generation of scientists through undergraduate research opportunities and outreach activities for rural middle-school students.The proposed work is to synthesize cadmium free, colloidal core/shell nanocrystals and to characterize their ensemble charge carrier dynamics using femtosecond fluorescence upconversion spectroscopy. In parallel, the best performing structures will be identified by correlating fluorescence dynamics at the single nanocrystal level with the same particle's atomic structure and chemical composition determined using high resolution high angle annular darkfield scanning transmission electron microscopy (HAADF-STEM) in conjunction with energy dispersive spectroscopy mapping (STEM-EDS) utilizing Vanderbilt's Tecnai Osiris. The information gained through the ensemble carrier dynamics and the correlation study provides a target to improve the current synthesis methodology.