Semiconductor-Heterojunction Approaches to Solar Water Splitting

Solar electricity is becoming ever cheaper, but the costs associated with the storage of this renewable electrical energy make it economically uncompetitive with fossil fuels. Although new (cheaper) battery technologies may be suitable for day/night cycles of renewable electricity, the only practical approach for long-term (seasonal) storage of solar energy is fuels. Semiconductor-based photoelectrochemical water splitting is a solar energy conversion technology that converts solar power directly into a storable fuel (H₂). In this talk, I will discuss our recent efforts with Sb₂Se₃- and Cu₂O-based photocathodes for hydrogen production from water, as well as a molecular interface dipole approach for maximizing the photovoltage of semiconductor heterojunctions in both photoelectrochemical and photovoltaic systems.