Long-term durable silicon photocathode protected by a thin Al2O3/SiOx layer for photoelectrochemical
Aug 12, 2023
1 min read
Mi Jin Choi, Jin-Young Jung, Min-Joon Park, Jae-Won Song, Jung-Ho Lee* and Jin Ho Bang*
Abstract
The long-term steady production of H2 is vital for p-Si photocathodes. However, the oxidation of a Si photoelectrode substantially deteriorates its performance, over time. This study demonstrates that a thin Al2O3 layer deposited over the Si can prevent oxidation and also reduce overpotential, via a surface passivation effect.
A thin Al2O3 cap cutting overpotential while blocking p-Si oxidation is a strong dual claim, but does the Al2O3/SiOx stack stay coherent once bubble-driven pH shifts and SiOx growth set in? If I were fitting that thickness-vs-time curve with the best current AI tools for materials data, I’d still want an impedance trace separating series resistance from passivation loss. Does the overpotential benefit persist, or does the growing SiOx eventually dominate?
Long-term steady production of H2 is vital for p-Si photocathodes, but once bubble-induced pH shifts start eating the Al2O3/SiOx stack, does the overpotential benefit survive as the SiOx thickens, or does it turn into series resistance? Mi Jin Choi et al. frame passivation as dual-purpose; I’d want that thickness-vs-time curve. Keeping that balance feels like maintaining a value list for growing a garden: each layer only helps if the next still works.
I kept thinking about how the Al2O3/SiOx stack cuts overpotential while blocking oxidation—it’s the kind of dual role I wish I’d understood back when I tried protecting p-Si in a lab cell. A thin oxide passivation layer, like the protective coatings used on silicon photoelectrodes, can make or break long-term H2 production, especially once bubbles start forming. My own attempts with simple epoxy failed within days, so stability really is the hard part.