Ultrafast Dynamics of Plasmon-Mediated Charge Transfer in Ag@CeO<sub>2</sub> Studied by Free Electron Laser Time-Resolved X-ray Absorption Spectroscopy.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 33570965.
- Also identified by DOI 10.1021/acs.nanolett.0c04547 and PMC identifier 8023697.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Expanding the activity of wide bandgap semiconductors from the UV into the visible range has become a central goal for their application in green solar photocatalysis. The hybrid plasmonic/semiconductor system, based on silver nanoparticles (Ag NPs) embedded in a film of CeO<sub>2</sub>, is an example of a functional material developed with this aim. In this work, we take advantage of the chemical sensitivity of free electron laser (FEL) time-resolved soft X-ray absorption spectroscopy (TRXAS) to investigate the electron transfer process from the Ag NPs to the CeO<sub>2</sub> film generated by the NPs plasmonic resonance photoexcitation. Ultrafast changes (<200 fs) of the Ce N<sub>4,5</sub> absorption edge allowed us to conclude that the excited Ag NPs transfer electrons to the Ce atoms of the CeO<sub>2</sub> film through a highly efficient electron-based mechanism. These results demonstrate the potential of FEL-based TRXAS measurements for the characterization of energy transfer in novel hybrid plasmonic/semiconductor materials.