Pulsed laser-deposited n-Si/NiOx photoanodes for stable and efficient photoelectrochemical water splitting

An electrocatalytic and stable nickel oxide (NiOx) thin layer was successfully deposited on an n-Si (100) substrate by pulsed laser deposition (PLD), acting as a photoanode for efficient photo-oxidation of water under solar illumination. It was revealed that the formed n-Si/NiOx heterojunction with good Schottky contact could improve photogenerated charge separation, and thus n-Si photoanodes deposited with a 105 nm-thick NiOx electrocatalytic layer exhibited a photovoltage of similar to 350 mV, leading to greatly improved photoelectrochemical performances for water oxidation. The stability of the photoanode was significantly enhanced with the increasing thickness of NiOx protective layers. This study demonstrates a simple and effective method to enable the use of planar n-Si (100) substrates as efficient and durable photoanodes for practical solar water oxidation.