Renee Frontiera

Spectroscopic Probes of Plasmon-Driven Chemical Reactions

Plasmonic materials are highly promising photoredox catalysts for driving energetically unfavorable chemical reactions with light, due to their large optical cross sections and ability to generate a number of hot holes and electrons. However, the efficiencies of most plasmon-driven processes are quite low, likely due to the lack of mechanistic understanding of the underlying physical processes. Plasmons can concentrate electromagnetic fields, can generate highly energetic electrons and holes, and can heat up local environments. An understanding of the energy partitioning into each of these processes is crucial to the design of plasmonic photocatalysts which are optimized for chemical selectivity. Here I’ll discuss our development of ultrafast surface-enhanced Raman spectroscopy (SERS) to probe the contributions of plasmon-generated hot electron transfer, heating, and vibrational energy transfer on timescales relevant to photocatalysis. Finally, I’ll discuss our discovery of a highly selective plasmon-driven methyl migration reaction in which the plasmonic substrate can provide nanoscale spatial control of reactivity. These efforts in developing a fundamental understanding of plasmon-mediated processes in molecules will ultimately aid in the rational design of cost-effective plasmonic materials capable of driving industrially relevant chemistries using solar radiation.