The Macromolecular, Supramolecular, and Nanochemistry (MSN) program of the Division of Chemistry supports the CAREER Award's research and education program of Prof. Javier Vela at Iowa State University. Prof. Vela and his students investigate new surface ligand doping strategies that enable to control the degree of functionalization or valency per nanocrystal. As part of this effort, Prof. Vela's group will investigate the changes in ligand organization, surface chemistry and nanocrystal properties that result from surface modification. Controlling the degree of functionalization per nanocrystal remains an unsolved challenge in colloidal semiconductors. Surface modification is routinely performed by ligand exchange with excess carboxylate- or amine-terminated thiols. However, this method fails to control the extent of surface modification. To solve this problem, Prof. Vela and his students will synthesize surface-doped quantum dots capped with chemically-active native ligands and characterize their surface microstructures, synthesize modular functional polydentate ligands for surface-doping and study their ligand exchange behavior with quantum dots, and explore the use of surface-doped quantum dots for lanthanide optical activation and rationing of rare earths. This research will positively impact our ability to fine-tune the number and relative configuration of energy- and charge-transfer donors and acceptors, providing unprecedented control over exciton decay pathways across the inorganic-organic-solvent interface.
Success of this research will result in powerful strategies to fabricate, assemble and discover functional nanomaterials for imaging, biology, energy and catalysis. For example, the extent of surface coverage by a particular functional group will impact a nanocrystal's surface affinity and permeability, and its ability to localize, penetrate, and be transported across biological tissues and subcellular structures. In addition, advanced characterization of surface-doped nanocrystals will further our understanding of surface-ligand organization and of how this affects optoelectronic properties. The educational goals of this proposal are to close gaps in nanotechnology research and education by introducing a university-wide nano seminar series and a nanochemistry course at Iowa State University, and to broaden participation via diverse recruiting and bilingual activities for Hispanic and Latino/a students and families. A weekly seminar and a formal course will promote interactions and facilitate exchanges among nanotechnology researchers across departments. By communicating science in two languages, Prof. Vela will directly address a growing demographic to raise awareness and advocacy for nanoscience as a way to improve the community, the national economy, and the environment.
