(Invited) Photochemical Energy Conversion with Integrated Plasmonics

Abstract

Plasmonic nanostructures can dramatically increase the chemical reaction rates by providing more efficient solar-to-chemical energy conversion. Upon light excitation, metallic nanostructures sustain the collective oscillation of surface electrons, i.e. surface plasmons, producing local field enhancement and after one hundred femtoseconds decaying by generating a non-thermal distribution of hot carriers. Their consequent thermalization results in intense local heating of the nanostructures and their surrounding. All these effects can alter the reaction pathways and boost the reaction kinetics. Such discoveries have boosted the field of plasmonic photocatalysis, which aims at driving industrially-relevant chemical reactions using solar illumination. In this talk, I will present our recent progress in the fabrication of large-area plasmonic metasurfaces exhibiting a rich set of electromagnetic resonances and their integration in photoelectrochemical water splitting cells, direct alcohol fuel cells, and photochemical devices for hydrogen evolution. I will discuss the complex relationship between the optical resonances of the plasmonic metasurfaces with their chemical reactivity by distinguishing the various effects enhancing their photochemical performance. Finally, a new scanning photoelectrochemical method that provide the two-dimensional mapping of the chemical reactivity of plasmonic nanostructures on planar substrates with sub-micron resolution will be introduced.