CAREER: New Models for Controlling InP Nucleation, Growth, and Luminescence using Magic-Sized Clusters and Targeted Surface Chemistry

University Of Washington, Seattle WA

Investigators

Abstract

One of the hallmarks of modern society has been efficiently and effectively transforming energy from one form to another, which has enabled increased human productivity and aided economic development. As technologies mature, continued progress on this front requires developing new materials with new and improved function. As a result of their emergent, size-dependent properties, nanomaterials are forecasted to significantly shape the future of next generation energy technologies. Nanomaterial function relies on the ability of scientists to access these materials with uniform and precise atomic structures. This is an enormous challenge since nanomaterials contain hundreds to thousands of atoms and even a few atoms out of place can significantly alter their function. Research conducted under this CAREER award aims to address the fundamental challenges in controlling the composition and interfaces of nanomaterials with atom-level precision. The globally-relevant nature of this research is leveraged to advance the major educational goals of this project, namely to: 1) create an undergraduate specialization in Chemistry for Energy at the University of Washington (UW), 2) develop hands-on demonstration materials and workshops on the topic of colloidal nanoscience targeted to middle and high school students in collaboration with the UW Phi Lambda Upsilon (National Chemistry Honor Society) chapter, and 3) broaden participation in chemistry at the undergraduate, graduate and professional level through work with the Chemistry Women Mentorship Network, the UW Women in Chemical Sciences, and the NSF-supported Louis Stokes Alliance for Minority Participation program. The scientific goal of this award is to understand how indium phosphide (InP) and related colloidal quantum dots (QDs) nucleate and grow in solution and how to rationally modify that mechanism and the properties of the resulting nanocrystals using surface chemistry. As a step toward this goal, several themes are initiated to provide the experimental context in which nucleation, growth, and photoluminescence modulation in these materials can be studied. These include: 1) testing new models of InP nucleation using isolable, structurally characterized and atomically precise magic-sized cluster intermediates; 2) understanding how surface chemistry impacts the structure and function of InP magic-sized clusters to gain access to general strategies for anisotropic shape control and doping; and 3) discovering new post-synthetic surface chemistry to turn-on and color-tune the luminescence of InP and related QDs using Lewis acid coordination chemistry. The research approach focuses primarily on the development of new hypothesis-driven synthetic methods as well as spectroscopic and theoretical characterization of the properties and electronic structure of these materials. Ongoing collaborations with experts in time-dependent electronic structure theory, X-ray crystallography, and X-ray photoelectron spectroscopy are leveraged to help answer fundamental structural and mechanistic questions. The educational component addresses the need to train the next generation of scientists and engineers to solve scientific grand challenges through the development of relevant and applicable lecture materials, learning tools and demonstrations.