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Picosecond Stabilization of Transferred Charge Carriers at Plasmonic Metal-Molecule Interfaces
Daniel Sandner1, Katrin Schulz1, Andrei Stefancu2
1Chair for Laser- and X-ray physics E11, TUM School of Natural Sciences, Technical University of Munich, James-Franck Str. 1, 85748, Garching, Germany.
Angewandte Chemie (International Ed. in English)
|November 3, 2025
Summary
Investigating charge transfer dynamics using femtosecond spectroscopy reveals that plasmonic nanoparticles facilitate energy transfer. Transferred charge carriers stabilize via solvation and polaron formation, extending back-transfer times beyond the sub-picosecond timescale.
Area of Science:
- Physical Chemistry
- Materials Science
- Spectroscopy
Background:
- Plasmonic nanoparticles efficiently absorb light, enabling energy transfer for photocatalysis.
- The precise role and timescale of charge carriers in these processes are debated.
Purpose of the Study:
- To investigate charge transfer dynamics in molecules adsorbed on silver nanoparticles.
- To elucidate the nature and timescale of charge carrier involvement in plasmon-enhanced energy transfer.
Main Methods:
- Broad-band femtosecond time-resolved infrared spectroscopy (1100-3000 cm⁻¹) was used.
- Probed free charge carrier dynamics and light-induced molecular IR mode changes.
Main Results:
- Charge transfer was observed upon resonant plasmon excitation with adsorbed molecules.
- Dynamics varied with probe frequency and molecular identity.
- Evidence for charge carrier stabilization via solvation and polaron formation was found.
Conclusions:
- Charge back-transfer time constants exceed the sub-picosecond regime, indicating complex relaxation.
- Strong charge carrier-adsorbate interactions were confirmed by parallel temporal evolutions.
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