Colin D. Heyes from the University of Arkansas is supported by the Macromolecular, Supramolecular and Nanochemistry Program in research focused on understanding how the optical and electrical properties of semiconductor quantum dots (QDs) are related to the structure of the core-shell interface at the single particle level. As the applications of bandgap-engineered core-shell nanomaterials approach the ultimate level of sensitivity - single particles and single photons - improving our understanding of the role of the critical core-shell interface is of paramount importance. In this proposal, expertise in the controlled synthesis of core-shell materials of varying composition combined with single particle spectroscopy and advanced high resolution electron microscopy techniques will be used to investigate how the trap states at the core-shell interface contribute to the charge carrier relaxation pathways by 1) synthesizing a range of core-shell and core-multishell QDs with different lattice mismatches and structurally characterizing these interfaces in single particles; 2) determining the ensemble and microscopic optical and electrical properties and correlating them to the structure of the core-shell interface; and 3) investigating how these properties are coupled to the shell-ligand interface and the local environment of the particle.
Core-shell quantum dots have wide ranging significance for photovoltaics, optoelectronics, photocatalysis and advanced biological imaging applications. This broad range of applications stems from the fact that the shell can be tuned to either enhance emission or to promote charge carrier trapping, separation and interfacial transfer. In order to advance such a range of technological fields, enthusing and training students in the multi-disciplinary aspects of modern physical chemistry is needed. The education and outreach aspects of this proposal will address this issue on three fronts. 1) expose and enthuse undergraduates (juniors and seniors) from local primarily undergraduate institutions (PUIs) by holding a summer workshop that exposes them to modern physical chemistry techniques in the form of performing recently published experiments at the interface of chemistry, physics and biology; 2) use this workshop to recruit under-represented minorities by targeting PUIs with a large body of such students, and 3) disseminate videos of the workshop experiments being performed via the principal investigator's website, YouTube and Facebook to broaden the educational impact to other PUIs, high schools and the general public.
