Photoelectrochemical Conversion Processes

Abstract

Society’s electrical needs are largely continuous. However, clouds and darkness dictate that photovoltaic solar cells have an intermittent output. A photoelectrochemical solar cell (PEC ) can generate not only electrical but also electrochemical energy, and provide the basis for a system with an energy storage component. Sufficiently energetic insolation incident on semiconductors can drive electrochemical oxidation/reduction and generate chemical, electrical or electrochemical energy. Aspects include efficient dye sensitized or direct solar to electrical energy conversion, solar electrochemical synthesis (electrolysis), including water splitting to form hydrogen, environmental cleanup and solar energy storage cells. The PEC utilizes light to carry out an electrochemical reaction, converting light to both chemical and electrical energy. This fundamental difference of the photovoltaic (PV ) solar cell’s solid/solid interface, and the PEC’s solid/liquid interface has several ramifications in cell function and application. Energetic constraints imposed by single bandgap semiconductors have limited the demonstrated values of photoelectrochemical solar to electrical energy conversion efficiency to 16 %, and multiple bandgap cells can lead to significantly higher conversion efficiencies.