A central goal of photochemistry is to address growing global energy demands while achieving net-zero emissions by enabling multistep reaction pathways that produce energy-dense fuels and chemicals. Advances in nanophotonics, particularly plasmonic hybrid nanostructures, offer a promising route by harnessing localized surface plasmon resonances (LSPRs) to drive light-induced chemical transformations. These resonances are tunable and wavelength-dependent, allowing precise control over catalytic activity, selectivity, and efficiency for sustainable energy applications. This thesis develops plasmonic metasurfaces with tunable resonances using strategies such as mode hybridization, polarization control, and phase-change materials. These systems drive reactions via two non-thermal LSPR mechanisms: near-field enhancement and hot-electron transfer. Their catalytic performance is studied using the N-demethylation of methylene blue, monitored in real time with surface-enhanced Raman spectroscopy. First, Au nanoparticle–cavity structures coupled with Fabry–Pérot modes enable over 100-fold modulation in product yield through spectral tuning. Second, elliptical Au nanodisk metasurfaces achieve polarization-dependent control, allowing rapid and predictable tuning of reactivity. Finally, integrating Sb2S3 phase-change cavities enables reversible resonance shifts and dynamic catalytic modulation. Overall, this work demonstrates precise control of photochemical reactivity via engineered plasmonic resonances strength, providing a scalable framework for efficient, selective solar-driven chemical synthesis.
Ning Lyu (Thu,) studied this question.