Dataset Information

Ultrafast Dynamics of Plasmon-Mediated Charge Transfer in Ag@CeO₂ Studied by Free Electron Laser Time-Resolved X-ray Absorption Spectroscopy.

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 CeO₂, 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 CeO₂ film generated by the NPs plasmonic resonance photoexcitation. Ultrafast changes (<200 fs) of the Ce N_4,5 absorption edge allowed us to conclude that the excited Ag NPs transfer electrons to the Ce atoms of the CeO₂ 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.

SUBMITTER: Pelli Cresi JS

PROVIDER: S-EPMC8023697 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature

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Ultrafast Dynamics of Plasmon-Mediated Charge Transfer in Ag@CeO<sub>2</sub> Studied by Free Electron Laser Time-Resolved X-ray Absorption Spectroscopy.

Pelli Cresi Jacopo Stefano JS Principi Emiliano E Spurio Eleonora E Catone Daniele D O'Keeffe Patrick P Turchini Stefano S Benedetti Stefania S Vikatakavi Avinash A D'Addato Sergio S Mincigrucci Riccardo R Foglia Laura L Kurdi Gabor G Nikolov Ivaylo P IP De Ninno Giovanni G Masciovecchio Claudio C Nannarone Stefano S Kopula Kesavan Jagadesh J Boscherini Federico F Luches Paola P

Nano letters 20210211 4

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) t ...[more]

PMID: 33570965

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Project description:The structures of a number of stereoisomers of carotenoids have been revealed in three-dimensional X-ray crystallographic investigations of pigment-protein complexes from photosynthetic organisms. Despite these structural elucidations, the reason for the presence of stereoisomers in these systems is not well understood. An important unresolved issue is whether the natural selection of geometric isomers of carotenoids in photosynthetic pigment-protein complexes is determined by the structure of the protein binding site or by the need for the organism to accomplish a specific physiological task. The association of cis isomers of a carotenoid with reaction centers and trans isomers of the same carotenoid with light-harvesting pigment-protein complexes has led to the hypothesis that the stereoisomers play distinctly different physiological roles. A systematic investigation of the photophysics and photochemistry of purified, stable geometric isomers of carotenoids is needed to understand if a relationship between stereochemistry and biological function exists. In this work we present a comparative study of the spectroscopy and excited state dynamics of cis and trans isomers of three different open-chain carotenoids in solution. The molecules are neurosporene (n = 9), spheroidene (n = 10), and spirilloxanthin (n = 13), where n is the number of conjugated pi-electron double bonds. The spectroscopic experiments were carried out on geometric isomers of the carotenoids purified by high performance liquid chromatography (HPLC) and then frozen to 77 K to inhibit isomerization. The spectral data taken at 77 K provide a high resolution view of the spectroscopic differences between geometric isomers. The kinetic data reveal that the lifetime of the lowest excited singlet state of a cis-isomer is consistently shorter than that of its corresponding all-trans counterpart despite the fact that the excited state energy of the cis molecule is typically higher than that of the trans molecule. Quantum theoretical calculations on an n = 9 linear polyene were carried out to examine this process. The calculations indicate that the electronic coupling terms are significantly higher for the cis isomer, and when combined with the Franck-Condon factors, predict internal conversion rates roughly double those of the all-trans species. The electronic effects more than offset the decrease in coupling efficiencies associated with the higher system origin energies and explain the observed shorter cis isomer lifetimes.

Project description:The structures of a number of stereoisomers of carotenoids have been revealed in three-dimensional X-ray crystallographic investigations of pigment-protein complexes from photosynthetic organisms. Despite these structural elucidations, the reason for the presence of stereoisomers in these systems is not well understood. An important unresolved issue is whether the natural selection of geometric isomers of carotenoids in photosynthetic pigment-protein complexes is determined by the structure of the protein binding site or by the need for the organism to accomplish a specific physiological task. The association of cis isomers of a carotenoid with reaction centers and trans isomers of the same carotenoid with light-harvesting pigment-protein complexes has led to the hypothesis that the stereoisomers play distinctly different physiological roles. A systematic investigation of the photophysics and photochemistry of purified, stable geometric isomers of carotenoids is needed to understand if a relationship between stereochemistry and biological function exists. In this work we present a comparative study of the spectroscopy and excited state dynamics of cis and trans isomers of three different open-chain carotenoids in solution. The molecules are neurosporene (n=9), spheroidene (n=10), and spirilloxanthin (n=13), where n is the number of conjugated pi-electron double bonds. The spectroscopic experiments were carried out on geometric isomers of the carotenoids purified by high performance liquid chromatography (HPLC) and then frozen to 77 K to inhibit isomerization. The spectral data taken at 77 K provide a high resolution view of the spectroscopic differences between geometric isomers. The kinetic data reveal that the lifetime of the lowest excited singlet state of a cis-isomer is consistently shorter than that of its corresponding all-trans counterpart despite the fact that the excited state energy of the cis molecule is typically higher than that of the trans molecule. Quantum theoretical calculations on an n=9 linear polyene were carried out to examine this process. The calculations indicate that the electronic coupling terms are significantly higher for the cis isomer, and when combined with the Franck-Condon factors, predict internal conversion rates roughly double those of the all-trans species. The electronic effects more than offset the decrease in coupling efficiencies associated with the higher system origin energies and explain the observed shorter cis isomer lifetimes.

Dataset Information

Ultrafast Dynamics of Plasmon-Mediated Charge Transfer in Ag@CeO₂ Studied by Free Electron Laser Time-Resolved X-ray Absorption Spectroscopy.

Publications

Ultrafast Dynamics of Plasmon-Mediated Charge Transfer in Ag@CeO<sub>2</sub> Studied by Free Electron Laser Time-Resolved X-ray Absorption Spectroscopy.

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Ultrafast Dynamics of Plasmon-Mediated Charge Transfer in Ag@CeO2 Studied by Free Electron Laser Time-Resolved X-ray Absorption Spectroscopy.

Publications

Ultrafast Dynamics of Plasmon-Mediated Charge Transfer in Ag@CeO<sub>2</sub> Studied by Free Electron Laser Time-Resolved X-ray Absorption Spectroscopy.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Ultrafast Dynamics of Plasmon-Mediated Charge Transfer in Ag@CeO₂ Studied by Free Electron Laser Time-Resolved X-ray Absorption Spectroscopy.