Trap Assisted Dynamical Processes in Semiconductor Nanocrystals

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The Macromolecular, Supramolecular and Nanochemistry (MSN) Program supports Professors Xiaosong Li and David Gamelin of the University of Washington to develop new nanoscale chemical structures that are useful for the emergence of next-generation information processing or energy conversion technologies. Chemical processes in semiconductor nanostructures are ubiquitous in energy conversion, energy storage, and efficient lighting, as well as in information processing and storage technologies. This integrated approach of synthesis, spectroscopy, and theory yields new and powerful avenues for describing fundamental properties that govern the important chemical processes in functional semiconductor nanostructures. This collaborative project, which involves both theoretical calculations and experimental synthesis and measurement also provides a mechanism for advanced interdisciplinary education and training that spans materials science, theory, inorganic chemistry, electronic structure analysis, dynamics analysis, and spectroscopy, and prepares participating undergraduate and graduate students for future careers in science and technology. Through a combination of high-school and community outreach, undergraduate research mentoring, and engagement with faculty at primarily undergraduate institutions, this project promotes and fosters participation of a broad spectrum of youth in science and engineering activities.This project uses a balanced theoretical and experimental approach to develop a fundamental understanding of various trap-assisted dynamical processes in semiconductor nanostructures. New computational methods using a first-principles spin-Hamiltonian within the time-dependent density functional theory framework are being developed for predicting and modeling trap-assisted dynamical processes. New computational approaches in conjunction with spectroscopic/spectroelectrochemical techniques are applied to investigations of trap-state assisted energy transfer processes and excited state dynamics that allow their microscopic origins to be defined thoroughly. Key structural parameters within the nanocrystals are to be systematically chemically modified. Theoretical and experimental determination of the parameters allows modulation or control of trap-state assisted processes in impurity-containing semiconductor nanocrystals.