Solution-processed nickel oxide passivation on large-area silicon electrodes for efficient photoelectrochemical water splitting†

Photoelectrochemical water splitting is a promising technology for converting solar energy into chemical energy. For this system to be practically viable, the materials and processes employed for photoelectrode fabrication should be cost-effective and scalable. Herein, we report the large-scale fabrication of nickel oxide-coated n-type silicon (n-Si) photoanodes via chemical bath deposition for efficient photoelectrochemical water oxidation. The conditions for depositing the nickel oxide-based passivation coating on n-Si electrodes were systematically optimized in terms of precursor immersion time and annealing temperature, while surface morphology and electrochemical properties were cautiously characterized. Finally, the fabrication of practically-useful large-area photoanodes were demonstrated by incorporating the solution-processed nickel oxide passivation layer onto 3-dimensionally structured 4-inch n-Si wafers with enlarged surface areas and diminished light reflection.