Solar hydrogen production by photoelectrochemical water splitting holds great promise for efficient solar energy harvesting and storage. To achieve spontaneous water splitting, developing efficient photoelectrodes with both high photovoltage and high photocurrent is highly desirable. However, current studied photocathodes such as p-Si, p-Cu2O and p-GaP have photovoltage lower than half of 1.23 V, the minimum voltage required for water splitting. To overcome these challenges, we are currently developing a photocathode using amorphous Si thin film with TiO2 encapsulation layer for efficient solar hydrogen production. With platinum as catalyst, a photocurrent onset potential of 0.93 V vs reversible hydrogen electrode potential and saturation photocurrent of 11.6 mA/cm2 are measured. This low-cost photocathode with high photo-voltage and current is a highly promising candidate for future tandem water splitting cells.
Project end date: 08/14/14