Resonance Energy Transfer Mediated by Metal–Dielectric Composite Nanostructures

Nanostructure-mediated energy transfer has attracted considerable attention as a template for photocatalysis and solar energy conversion, and the use of noble-metal nanoparticles that support localized surface plasmon resonances (LSPRs) has been widely explored as a medium for realizing this paradigm. On the other hand, composite nanoparticles (CNPs) comprised of a large dielectric bead and smaller metal nanostructures have been shown to achieve efficient energy transfer to small-molecule adsorbates through the interplay between dielectric scattering resonances and the broad-band absorption associated with the metal nanostructure. This scattering-mediated absorption can enable selective photochemistry without relying on the plasmonic properties of noble-metal nanoparticles. While the precise photochemical mechanisms themselves remain unknown, resonance energy transfer (RET) is one feasible route for initiating the photochemistry. We demonstrate computationally that CNPs indeed facilitate RET to small-molecule adsorbates and that CNPs offer a framework in which one can design RET donors that outperform typical plasmonic nanoparticles employed within LSPR-driven RET under comparable illumination conditions. We also exploit the tunability of the resonances on the CNPs to realize strong coupling between the CNP and LSPR modes.