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

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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.