Molecular Level Understanding of Dynamic Speciation to Inform Complex Reaction Pathways and Control the Rational Synthesis of Ternary Semiconductor Nanoparticles

With the support of the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry, Dr. Amy Prieto of Colorado State University is developing a synthetic toolkit for understanding and controlling the reactivity of selenium species that can direct the synthesis of phase pure ternary semiconductor nanoparticles. These nanomaterials, which are composed of non-toxic, earth-abundant elements, have the potential to offer tunable optoelectronic properties that could be exploited in photovoltaic devices.

Dr. Prieto involves high school, undergraduate, and graduate students in this research. The Prieto research team is also developing hands-on learning kits for middle school students that focus on solar cells to engage them in key energy topics.

This research involves elucidating how the precursor to monomer transformation of Se powder in high boiling point surfactants can yield phase-pure ternary semiconductor nanoparticles. This includes probing the speciation of reactive components that lead to phase pure copper selenophosphate nanoparticles by focusing on the Lewis acidity and basicity of selenium monomers, understanding these synthetic parameters to controllably access phosphorous deficient metastable C/P/Se nanoparticles, and extrapolating this chemistry to synthesize a new silver compound that contains both phosphorus and selenium.

This research is focusing on a diverse range of tools to identify solution species and crystalline products under both in-situ reaction conditions and post-synthesis. By developing this tool kit for the synthesis of semiconductor nanoparticles, reaction pathways for pure phase ternary and quaternary nanoparticles with tunable composition, structure, and surface chemistry are expected and these could be exploited in future photovoltaics.

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.