UC Irvine

Models of solar fuels devices that are completely electrochemically-mediated and consist of ensembles of optically thin light absorbers were used to calculate their maximum theoretical solar-to-fuel efficiencies. These models are based on the thermodynamic principles of detailed balance and blackbody radiation, semiconductor device physics, and simple catalysis. The maximum efficiency of an electrochemically-mediated tandem water splitting device was calculated and the crucial dependence of this efficiency on the redox shuttle thermodynamic potential was elucidated. A novel model of a stack of optically thin, radiatively coupled light-absorbers that each independently perform solar fuels reactions was developed to demonstrate the substantial gains in solar-to-fuel efficiency that are possible when using ensembles of small light-absorbers. The results presented herein can be used by researchers to develop high-efficiency, low-cost solar fuels materials and devices.