Photovoltaic and Photoelectrochemical Solar Energy Conversion with Cu2O

The amount of solar power striking the earth's surface is vastly superior to humanitys present day energy needs and can easily meet our increasing power demands as the worlds population grows. In order to make solar power cost competitive with fossil fuels, the conversion devices must be made as cheaply as possible, which necessitates the use of abundant raw materials and low energy intensity fabrication processes. Cuprous oxide (Cu2O) is a promising material with the capacity for low cost, large-scale solar energy conversion due to the abundant nature of copper and oxygen, suitable bandgap for absorption of visible light, as well as effective, low energy intensity fabrication processes such as electrodeposition. For photoelectrochemical (PEC) water splitting, protective overlayers have been developed that greatly extend the durability of hydrogen-evolving Cu2O-based materials. Recent developments in the advancement of protective overlayers for stabilizing photoabsorber materials for water splitting are discussed, and it is concluded that the use of protective overlayers is a viable strategy for practical water splitting devices.