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

TL;DR

This study uses a continuum solvation model to analyze how surface chemistry and interface properties influence the electrochemical stability and light-harvesting efficiency of silicon photoelectrodes in water-splitting applications.

Contribution

It introduces a self-consistent continuum solvation model to predict charge response, Schottky barriers, and stability of silicon surfaces under operational conditions.

Findings

Oxidized silicon surfaces are most stable but have poor Schottky barriers.

Passivated silicon electrodes show low solar-to-hydrogen efficiency.

Surface interactions significantly impact photoelectrode performance.

Abstract

We consider the factors that affect the photoactivity of silicon electrodes for the water-splitting reaction using a self-consistent continuum solvation (SCCS) 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.