To transition our energy economy into one that is fully sustainable and not dependent on fossil fuels, developing an economically viable “artificial photosynthetic” device for the overall storage of solar energy as chemical energy is an urgent goal. Using solar energy to drive the electrochemical production of fuels (e.g. the splitting of water into molecular hydrogen and oxygen) is a promising technology in this regard. High-efficiency solar-to-fuel energy conversion can be directly achieved using a photoelectrochemical (PEC) device consisting of an n-type photoanode in tandem with a p-type photocathode. However, the development of stable and inexpensive photoelectrodes are needed to make PEC devices economically viable.
In this presentation our laboratory’s progress in the development of economically-prepared, high performance photoelectrodes will be discussed along with the application toward overall PEC water splitting tandem cells. Specifically, how the use of scalable solution-processing techniques (e.g. colloidal processing of nanoparticles or sol-gels) leads to limitations in charge transport and charge transfer in the resulting thin-film photoelectrodes will be examined. Strategies to overcome these limitations using chemical innovations such as using charge extraction buffer layers, catalysts, annealing/doping and nanoparticle self-assembly will be additionally presented. Materials of interest are oxides (e.g. CuFeO2 ZnFe2O4), CIGS, 2D-layered WSe2, and semiconducting carbon-based materials.