posted on 2021-02-11, 19:05authored byJacopo Stefano Pelli Cresi, Emiliano Principi, Eleonora Spurio, Daniele Catone, Patrick O’Keeffe, Stefano Turchini, Stefania Benedetti, Avinash Vikatakavi, Sergio D’Addato, Riccardo Mincigrucci, Laura Foglia, Gabor Kurdi, Ivaylo P. Nikolov, Giovanni De Ninno, Claudio Masciovecchio, Stefano Nannarone, Jagadesh Kopula Kesavan, Federico Boscherini, Paola Luches
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 N4,5 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.