Inelastic Spectroscopy for Probing Plasmonic Energy Transfer in a Steady State

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Matthew Sheldon and his research team at the University of California, Irvine, are pursuing research to examine and understand the interaction between light and metals at the nano-level. This project is particularly interested in how these interactions can transform energy from light, such as sunlight, into chemical energy when molecules are near the metal surface. Understanding this process, especially when the properties of the incident light are very similar to sunlight, has great potential for renewable energy applications. Furthermore, the project promotes educational inclusion by offering first generation college students, especially from underrepresented backgrounds, opportunities to engage in cutting-edge research starting their freshman year, thereby supporting the national interest in scientific literacy and diversity in science and engineering fields. This project seeks to quantify the non-equilibrium electronic energy distribution in plasmonic metals and decipher its role in chemical transformations of analytes at the metal surface. Leveraging plasmonic nanostructures that can concentrate light, the research will dissect complex photochemical processes through inelastic spectroscopy, distinguishing between charge transfer due to photo-excited electrons versus those in an elevated temperature distribution. The technical aims are twofold: first, to quantify the behavior of these "hot electrons" and their involvement in surface chemistry, and second, to explore resonant vibrational energy transfer, a process that could aid strategies for mode-selective chemistry. Collectively, the insights gleaned from this research are expected to inform the steady-state dynamics of plasmonic photochemistry, thus broadening the scientific understanding of light-matter interactions and offering new perspectives on the mechanisms underlying sunlight-driven chemical processes. 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.