Dynamics of charge transfer from plasmonic nanoparticles to cerium oxide

The combination of semiconducting oxide-based materials with plasmonic nanoparticles (NPs) aims to efficiently convert solar light into chemical or electric energy, exploiting the excitation of localized surface plasmon resonance (LSPR) in the NPs that leads to a significant energy/charge transfer to the oxide. By performing UV-Visible spectrophotometry measurements on systems composed of Cu/Au NPs embedded in a matrix of CeO2, we observed a wide absorption band in the visible range, ascribed to the LSPR excitation in the NPs. Femtosecond transient absorption spectroscopy at different pump energies across the LSPR band of the NPs unveiled a persistent charge transfer from the NPs to CeO2. Efficiency up to 35% for systems with Au NPs has been estimated.