Stability and light capture are the two main challenges in making efficient photoelectrochemical (PEC) water splitting devices. While light capture can be optimized by engineering, for example, using a tandem cell of small and large bandgap semiconductors, no clear engineering path has been established to solve the inherent stability problem of the materials under the harsh environment during operation.
To reduce solution resistance and prevent pH gradient, PEC devices are normally operated under strong acid or strong alkaline
electrolyte which are highly corrosive to most semiconductors. Pourbaix diagrams are one of the tools to evaluate the thermodynamic
stability of the materials. However, the kinetics of the corrosion is still not known.
Majority of my research here at Caltech is to quantify the rate of corrosion of the corrosion mechanisms of semiconductors,
specifically in II-VIs, namely CdTe and ZnTe.