Solar water splitting: Efficiency discussion

Solar hydrogen production with electrical-to-hydrogen conversion efficiency of 52% is demonstrated using a simple ∼0.7%-efficient n-Si/Ni Schottky solar cell connected to a water electrolysis cell. This case study shows that separation of the processes of solar harvesting and electrolysis avoids photo-electrode corrosion and utilizes optimal electrodes for hydrogen and oxygen evolution reactions and achieves ∼10% efficiency in light-to-hydrogen conversion with a standard 18% efficient household roof Si-solar cells. Strategy to increase efficiency above 15% for a single junction cell is outlined.