Robust and Stable Atomically Precise Metal Nanoclusters Mediated Solar Water Splitting.

Area of Science:

• Materials Science
• Nanotechnology
• Photochemistry

Background:

• Atomically precise metal nanoclusters (NCs) show promise as light-harvesting antennas due to quantum confinement and discrete energy bands.
• Challenges remain in controlling charge carriers in metal NCs due to short lifetimes and instability, obscuring photoredox mechanisms.

Purpose of the Study:

• To demonstrate fine-tuning of charge migration over metal NCs.
• To enhance photoelectrochemical water oxidation by constructing directional charge transfer channels.

Main Methods:

• Utilized a facile layer-by-layer (LbL) assembly approach.
• Constructed multilayered heterostructures with oppositely charged branched poly-ethylenimine (BPEI) and glutathione (GSH)-capped gold NCs [Au$_{x}$ NCs, Au$_{25}$ (GSH)$_{18}$ NCs] on metal oxide substrates (TiO$_{2}$, WO$_{3}$, Fe$_{2}$O$_{3}$).

Main Results:

• Achieved directional charge transfer channels via BPEI intercalation between Au$_{x}$ NCs layers.
• Established a tandem hole transport channel, significantly enhancing photoelectrochemical water oxidation.
• Improved the photo-stability of Au$_{x}$ NCs by stimulating hole transfer kinetics.

Conclusions:

• The developed multilayered heterostructure effectively controls charge migration in metal NCs.
• This approach enhances light-harvesting antenna performance for water oxidation.
• Overcame photo-instability issues in metal NCs through optimized charge transfer.