Solvated Electron Generation from Coupled Plasmon Modes of Gold Nanoparticles Using Visible Light

Area of Science:

• Physical Chemistry
• Materials Science
• Nanotechnology

Background:

• Solvated electrons are potent homogeneous reducing agents crucial for redox chemistry.
• Water's high photoemission barrier limits plasmon-mediated solvated electron generation to UV light.
• Developing visible-light methods is key to expanding accessible redox chemistry.

Purpose of the Study:

• To lower the photoemission threshold for visible light-driven solvated electron generation.
• To enhance solvated electron yields using plasmonic nanostructures.
• To provide mechanistic insights into optimizing solvated electron production.

Main Methods:

• Utilized hexamethylphosphoramide (HMPA) as an organic solvent to lower the photoemission threshold.
• Employed clustered gold nanoparticles to create coupled plasmon modes and enhance local electric fields.
• Varied nanoparticle density to correlate quantum yield with electric field enhancement.

Main Results:

• Achieved access to the entire visible spectrum for photoemission by using HMPA.
• Observed up to 150-fold higher solvated electron yields compared to smooth gold electrodes.
• Correlated quantum yield with local electric field enhancement from gap plasmon modes.

Conclusions:

• Hexamethylphosphoramide enables visible light-driven solvated electron generation.
• Clustered gold nanoparticles significantly enhance electron generation through plasmonic effects.
• Threshold optimization and plasmonic field enhancement are key strategies for efficient solvated electron production.