Electrochemical stability and light-harvesting ability of silicon photoelectrodes in aqueous environments

We study the factors that affect the photoactivity of silicon electrodes for the water-splitting reaction using a self-consistent continuum solvation model of the solid-liquid interface. This model allows us to calculate the charge-voltage response, Schottky barriers, and surface stability of different terminations while accounting for the interactions between the charge-pinning centers at the surface and the depletion region of the semiconductor. We predict that the most stable oxidized surface does not have a favorable Schottky barrier, which further explains the low solar-to-hydrogen performance of passivated silicon electrodes.