A General Concept for Solar Water-Splitting Monolithic Photoelectrochemical Cells Based on Earth-Abundant Materials and a Low-Cost Photovoltaic Panel

Like photosynthesis, where light is transformed into energy-rich molecules, sunlight energy can be converted into H-2 and O-2 using water-splitting photoelectrochemical cells (PECs). These systems are highly promising to produce H-2 without carbon emissions, however, their fabrication is still based on expensive fabrication procedures and nonabundant materials, which prevents their manufacturing and study by many laboratories. Here, an original concept for preparing monolithic water-splitting PECs based on the integration of a low-cost Si photovoltaic (PV) panel with two Si-based photoelectrodes fabricated by simple procedures and earth-abundant materials is demonstrated. In contrast with previous approaches, in the present system, the PV solid junction and the two solid/liquid junctions participate in the creation of the effective photovoltage applied for water splitting. This simple device that can split water from various electrolytes for several hours should promote new advances in the field of solar fuels.