Light Management in Extremely Thin Photoelectrode Architectures

Concepts from metamaterials, plasmonics and nanophotonics are expected to be highly beneficial for the design of future solar energy conversion devices. Here, I will describe how we use these concepts to design advanced photoelectrode architectures for two challenging photocatalytic reactions: water splitting and CO₂ reduction. We focus on the light management aspect in extremely thin absorber structures to achieve broadband omnidirectional solar absorption while carefully choosing materials systems that allow for efficient charge separation and catalytic activity.

               I will discuss the benefits of employing thin-film absorber photoelectrodes, which include the potential for enhanced charge carrier extraction, increased photovoltages and the possibility to exploit hot carriers for purposes of driving chemical reactions. I will also discuss our analytical models and three-dimensional electromagnetic simulations that we employ to meticulously engineer light absorption in two-dimensional materials and plasmonic metal nanostructures. Complementing these materials and device design efforts, we are developing an experimental characterization toolbox, including photoelectrochemical techniques and ultrafast spectroscopic techniques that will allow us to analyze the influence of distinct plasmon-induced effects (e.g., near-field concentration, hot charge carriers, heat generation) and non-plasmonic effects (e.g., sample morphology, catalytic and electronic effects, charge separation and recombination) on photocatalysis.