Photoelectrochemical and Photovoltaic Characteristics of Amorphous-Silicon-Based Tandem Cells as Photocathodes for Water Splitting

In this study amorphous silicon tandem solar cells are successfully utilized as photoelectrodes in a photoelectrochemical cell for water electrolysis. The tandem cells are modified with various amounts of platinum and are combined with a ruthenium oxide counter electrode. In a two-electrode arrangement this system is capable of splitting water without external bias with a short-circuit current of 4.50 mA cm(-2). On the assumption that no faradaic losses occur, a solar-to-hydrogen efficiency of 5.54% is achieved. In order to identify the relevant loss processes, additional three-electrode measurements were performed for each involved half-cell.