Cascading Interfaces Enable n-Si Photoanodes for Efficient and Stable Solar Water Oxidation

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• Efficient photoelectrochemical (PEC) water splitting relies on optimized interfacial charge transfer and catalysis.
• Silicon (Si) photoanodes offer high solar absorption but require effective stabilization and catalytic layers.

Purpose of the Study:

• To design and implement cascading interfaces on n-Si photoanodes for improved solar water splitting.
• To enhance charge transfer dynamics and water oxidation kinetics for efficient hydrogen generation.

Main Methods:

• Atomic layer deposition (ALD) of a CoOₓ protective layer on n-Si.
• Coating with an earth-abundant NiCuOₓ layer for catalysis.
• Characterization of the n-Si/CoOₓ/NiCuOₓ triple junction and its interfacial properties.

Main Results:

• The n-Si/CoOₓ/NiCuOₓ structure promoted solid/solid interfacial charge transfer.
• Cascading interfaces generated significant band bending, enhancing photovoltage and charge separation.
• An in situ formed NiCu(OH)ₓ/NiOOH active layer accelerated water oxidation kinetics.

Conclusions:

• The developed cascading interfaces effectively stabilize and catalyze n-Si photoanodes.
• This approach offers a promising strategy for efficient solar water oxidation and hydrogen production.