Plasmon-Induced Electron-Hole Separation at the Ag/TiO₂(110) Interface.

Area of Science:

• Materials Science
• Surface Science
• Computational Chemistry

Background:

• Plasmon-induced electron-hole separation is crucial for photovoltaics, photochemistry, and optoelectronics.
• The precise mechanism and dynamics of charge separation under plasmon excitation remain poorly understood.

Purpose of the Study:

• To investigate the mechanism and dynamics of plasmon-induced charge separation at a silver nanocluster (Ag20) and titanium dioxide (TiO2(110)) interface.
• To elucidate the role of plasmon-electron coupling and charge-transfer plasmon dynamics in hot carrier generation and separation.

Main Methods:

• Time-dependent density functional theory (TD-DFT) simulations were employed.
• The study focused on the Ag20/TiO2(110) interface to model plasmon excitation and subsequent charge dynamics.

Main Results:

• Charge separation occurs in two stages: initial separation via plasmon-electron coupling and subsequent redistribution driven by charge-transfer plasmon motion.
• Hot electrons are more effective in charge injection than hot holes, leading to efficient spatial separation (>40% of electron-hole pairs).
• An inhomogeneous, layer-dependent distribution of hot carriers is observed, with the second TiO2 layer accumulating the most net charge.

Conclusions:

• The study reveals the detailed mechanism and dynamics of plasmon-driven charge separation at metal-semiconductor interfaces.
• Findings provide insights into hot carrier generation, separation, and distribution, crucial for optimizing plasmonic devices.
• Results have significant implications for the design and application of plasmonic nanomaterials in energy conversion and optoelectronics.