All else being equal: Structuring in electrochemical materials for making solar fuels.

by Coridan, Robert

Semiconductor-based photoelectrochem. materials can be used to drive the conversion of solar energy to chem. fuels. Researchers borrow the design of natural photosynthetic complexes to engineer integrated assemblies of light absorbers, electrocatalysts, and membranes. These assemblies are designed to drive targeted reactions that store solar energy to be used on demand, like splitting water to hydrogen+oxygen or converting carbon dioxide to useful hydrocarbons like methane, ethylene, or methanol. Our research focuses on how the organization of these components can effect the fundamental efficiency and kinetics that govern these reactions, all else being equal. In this talk, I will introduce the chem. and materials science involved in photoelectrochem. artificial photosynthesis. I will also describe some of our efforts to address issues involving the design of hierarchically structured materials for these applications. Examples of questions we consider include how to best organize electrocatalysts on semiconductor-electrolyte interfaces to account for the electrolytic growth of gas bubbles on the surface, how to grow thin films in three dimensions to simultaneously maximize light absorption and carrier collection in materials with poor electronic properties, and to identify ways to 'trick' semiconductors to optimize their ability to absorb light while they grow.