Structure-Induced Stability In Sinuous Black Silicon For Enhanced Hydrogen Evolution Reaction Performance

Clean energy infrastructures of the future depend on efficient, low-cost, long-lasting systems for the conversion and storage of solar energy. This is currently limited by the durability and economic viability of today's solar energy systems. These limitations arise from a variety of technical challenges; primarily, a need remains for the development of stable solar absorber-catalyst interfaces and improved understanding of their mechanisms. Although thin film oxides formed via atomic layer deposition have been widely employed between the solar absorber-catalyst interfaces to improve the stability of photoelectrochemical devices, few stabilization strategies have focused on improving the intrinsic durability of the semiconductor. Here, a sinuous black silicon photocathode (s-bSi) with intrinsically improved stability owing to the twisted nanostructure is demonstrated. Unlike columnar black silicon with rapidly decaying photocurrent density, s-bSi shows profound stability in strong acid, neutral, and harsh alkaline conditions during a 24-h electrolysis. Furthermore, scanning transmission electron microscopy studies prior to and post electrolysis demonstrate limited silicon oxide growth inside the walls of s-bSi. To the authors' knowledge, this is the first time structure-induced stability has been reported for enhancing the stability of a photoelectrode/catalyst interface for solar energy conversion.