In this project, funded by the Chemical Structure, Dynamics & Mechanisms-B Program of the Chemistry Division, Professor George Christou of the Department of Chemistry at the University of Florida is using synthetic chemistry methods to prepare nanoparticles of important metal oxides that are identical in size and shape. Such "molecular nanoparticles" (molecules less than one billionth of a meter in size) address an important current challenge in nanoscience, namely how to avoid mixtures of sizes and shapes, and thus of properties. Most current preparations of nanoparticles result result in various particle sizes and shapes in the same batch. The project is initially targeted at making molecular nanoparticles of cerium dioxide and manganite perovskites, materials of widespread importance in industrial and medical applications, as well as potentially new quantum device technologies. Professor Christou and his group carry out a number of outreach, education and international activities. They participate in the annual Chemistry Day at the Mall in Gainesville, targeted at K-12 students, teachers and parents, and the local community and media. Undergraduate research students participate in hands-on research gaining important skills for graduate work or employment. Professor Christou organizes the Showcase Symposium at the annual meeting of the Florida ACS Local Section, and also organizes the annual Florida Inorganic and Materials Symposium student meeting, which involves 14 Florida PhD-granting universities, and undergraduate and community colleges. Internationally, he co-organizes two biennial workshops, the Current Trends in Molecular and Nanoscale Magnetism (2021), and the North America-Greece-Cyprus Workshop on Paramagnetic Materials (2020, 2022), which include many talks from students and postdocs. Finally, the team continues to collaborate with national and international groups, providing samples for specialized physics studies, and assisting synthetic chemists in the magnetic characterization of their materials.
Synthesis of truly monodisperse (identical) nanoparticles and their structural characterization at atomic resolution are extremely important challenges in nanoscience. For many nanoscale materials important to the development of next-generation electronic, magnetic, catalytic, and biomedical systems/devices, the top-down approach has limitations as the fabrication of monodisperse nanoparticles becomes more and more difficult with decreasing size. The bottom-up molecular approach provides an alternative route if high nuclearity clusters that have the same structure as the bulk material can be synthesized. Such "molecular nanoparticles" bring the advantages of molecular chemistry to nanoscience, particularly true monodispersity, solubility, and crystallinity. This synthetic approach is especially available nanoscale metal oxides, which are of scientific and technological importance. Breakthroughs in cluster chemistry to produce truly monodisperse nanoparticles of manganite perovskites and cerium dioxide have recently been achieved by the Professor George Christou's group, opening up new directions that promise knowledge generation at the nanoscale.
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.
