NSF Award
2204039
With support from the Macromolecular, Supramolecular, and Nanochemistry (MSN) Program in the Division of Chemistry, Ramakrishna Guda of Western Michigan University is working to create highly luminescent gold nanoclusters for optical applications. In large pieces, gold is metallic and does not emit light. However, when it is broken down to tiny clusters with only a smaller number of atoms, such gold cluster will emit light. While these luminescent gold clusters are photostable and less toxic than many semiconductors, their luminescence is not as bright. Dr. Guda and his students will work to rationally design and synthesize gold clusters that luminescence with greater quantum efficiencies and over a broad range of colors. Their discoveries could lead to nanoclusters for light harvesting and optical sensing applications. The project will also provide research opportunities for graduate and undergraduate students, as well as introduce nanoscience to high school students and their teachers through education workshops. <br/><br/>Atomically precise quantum-sized gold nanoclusters offer discrete electronic states, distinctive photoluminescence and exclusive excited-state relaxation that make them ideal candidates for various photonic applications. Achieving highly luminescent gold nanoclusters is challenging and is impeding their progress as photonic materials. The Guda research team will synthesize gold clusters with increased the rigidity of gold atoms at the cluster surface, with the goal of amplifying photoluminescence. The optical activity of gold clusters is expected to be further improved by judiciously functionalizing the surface with organic chromophores to achieve efficient energy transfer from a surface-bound chromophore to gold cluster or vice-versa. A combination of ultrafast time-resolved absorption and photoluminescence techniques will be used to unravel the mechanism of excited-state relaxation in these hybrid structures and provide feedback to design clusters with enhanced optical activity. The mechanistic studies are expected to shed light on intrinsic energy and charge transfer interactions between chromophores and atomically precise gold clusters.<br/><br/>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.
