RUI: Post-synthetic transformations of anions in metal chalcogenide nanoparticles: Uncovering synthetic design rules and the effect on subsequent transformations

Franklin And Marshall College, Lancaster PA

Investigators

Abstract

NON-TECHNICAL SUMMARY Applications of nanotechnology to problems like solar energy capture and storage and sustainable electronic devices rely on the ability to design nanoparticles with specific properties and chemical make-ups. With support from the Solid State and Materials Chemistry program in NSF’s Division of Materials Research, the principal investigator’s group at Franklin and Marshal College seek to develop new ways to design complex nanoparticles by starting with simple particles that we can make reproducibly that have only two components–the elements copper and sulfur and then swapping-out the sulfur component with the related elements selenium and tellurium. This represents a new chemical approach to making many-component nanoparticles. It is expected that by targeting the sulfur component, the PI’s team will be able to create nanoscale patterns that would not be achievable otherwise. Peer-mentored undergraduate student teams will carry out experimental work, receiving excellent training for careers in materials and other STEM fields. Through the nanobots Early College Research Experience, first- and second-year students will perform computational modeling of these processes. The Early College Research Experience is an inclusive and supportive research cohort intended to create a welcoming entry to STEM that will encourage a diverse set of students to continue with research and STEM coursework. TECHNICAL SUMMARY Post-synthetic transformations of nanoparticles can create complex multi-component nanoheterostructures. Cu2-xS nanoparticles are common starting materials for cation exchanges, forming the basis for whole libraries of nanoparticles through repeated partial cation exchanges. Despite the success of cation exchange in nanoheterostructure design, anion exchange has been much less implemented. The PI’s group has recently developed selenide and telluride anion exchange transformations of Cu2-xS nanorods. This project, with support from the Solid State and Materials Chemistry program in NSF’s Division of Materials Research, will seek to better understand how these anionic transformations affect Cu2-xS nanoparticles, how broadly applicable these transformations are, and how they affect plasmonic properties, regioselectivity of new components, and defect formation. Addtionally, molecular dynamics simulations will be used to gain mechanistic insight into the post-synthetic transformation processes. Finally, anionic transformations will be coupled with secondary transformations to uncover the interplay of the design rules guiding post-synthetic transformations. This fundamental work will advance knowledge of how to design nanoparticle heterostructures a priori, affording new routes to materials for optoelectronic applications. The metal chalcogenide particles investigated have the potential to act as catalysts, solar energy absorbers in PV or solar water evaporation, NIR absorbers in photothermal cancer treatment, sensors, or thermoelectrics. Activities are proposed that strengthen training in materials chemistry through undergraduate research with close student-faculty interaction and innovative partnerships between PUI and R1 laboratories, all of which improve student training and sense of belonging through peer- and near-peer mentoring structures. 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.