High performance H-2 evolution realized in 20 mu m-thin silicon nanostructured photocathodes

Abstract

Thickness reduction in high-purity silicon wafers is beneficial for cost-efficient hydrogen evolution utilizing silicon photocathodes. However, two major issues need to be resolved: insufficient light absorption by a thin Si absorber and poor charge transfer reaction by dominant surface recombination. Here, we present 20 mm-thin Si photocathodes employing Pt-nanoparticle-coated silicon nanoholes that realize a photocurrent of 23 mA cm(-2) (at 0 V vs. RHE) corresponding to the amount typically achieved by a conventional wafer (similar to 200 mm-thick).