Development of a Hybrid Photoelectrochemical (PEC) Device with Amorphous Silicon Carbide as the Photoelectrode for Water Splitting

We report on an integrated photoelectrochemical (PEC) device for hydrogen production using amorphous silicon carbide (a-SiC:H) material as the photoelectrode in conjunction with an amorphous silicon (a-Si:H) tandem photovoltaic device. With the use of a-Si:H tandem solar cell, the flat-band potential of the hybrid PEC structure shifts significantly below the H ₂O/O₂ half-reaction potential and is in an appropriate position to facilitate water splitting. Under reverse bias, saturated photocurrent of the hybrid device ranges between 3 to 5 mA/cm² under AM 1.5 light intensity. In a two-electrode setup (with ruthenium oxide counter electrode), which is analogous to a real PEC configuration, the hybrid cell produces photocurrent of about 0.83 mA/cm² at zero bias and hydrogen production is observed. The hybrid device exhibits good durability in pH2 buffered electrolyte for up to 150 hours (so far tested).