CAREER: Controlled Dopant Migration by Atomic Trapping for Site-Specific Doping in Nanocrystals

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Dopants are impurity atoms that are intentionally introduced into host materials to improve physical properties and behavior (or functionality). Professor Zheng and his research group at Syracuse University are developing reliable methods for the effective incorporation of dopants into nanocrystals (of dimensions about 1/1000 times the width of human hair) at specific locations. This project represents a detailed investigation of dopant movement and migration behavior inside nanocrystals. The research addresses fundamental questions about the composition-dependent properties of nanomaterials. The results of this research could have implications in many emergent technologies such as solar energy harvesting, solid-state lighting, and quantum computing. The research performed under this project will be used as a tool to initiate anannual program of Materials Chemistry behind Table Tennis at the East Syracuse Minoa High School. The research on the dopant location dependent properties of nanocrystals will be linked to the micro-composition-dependent performance of table tennis gear. By discussing the science behind sport, the program will be highly interactive and make materials chemistry more approachable to students. The educational plan improves the active learning process among middle and high school students, fosters interest in STEM education at their early ages, and develops science teaching skills for STEM undergraduate and graduate students.Professor Zheng is supported by the Macromolecular, Supramolecular, and Nanochemistry Program of the NSF Division of Chemistry to explore directional dopant migration behavior and systematically control dopant location and distribution inside host semiconductor nanocrystals. The goal of the project is to determine how the dopant spatial distribution is modified under the influence of local lattice composition and strain during surface shell passivation and functionalization in core/shell nanocrystals. The team is utilizing local nanocrystal lattices with relatively small cationic size mismatch relative to that of the dopants as an "atomic trap". They initiate fast dopant migration inside nanocrystals under moderate temperatures. Controlled dopant migration for specific dopant locations inside core/shell NCs can fine tune the host-to-dopant coupling, which offers new opportunities to design novel nanomaterials with unprecedented properties for applications in dual-band optical sensors, white light emitters, and solar energy harvesters.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.