Determining Quasi-Equilibrium Electron and Hole Distributions of Plasmonic Photocatalysts using Photomodulated X-ray Absorption Spectroscopy

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Hauptverfasser: Palmer, Levi D., Lee, Wonseok, Dong, Chung Li, Liu, Ru-Shi, Wu, Nianqiang, Cushing, Scott K.
Format: Preprint
Veröffentlicht: 2023
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author Palmer, Levi D.
Lee, Wonseok
Dong, Chung Li
Liu, Ru-Shi
Wu, Nianqiang
Cushing, Scott K.
author_facet Palmer, Levi D.
Lee, Wonseok
Dong, Chung Li
Liu, Ru-Shi
Wu, Nianqiang
Cushing, Scott K.
contents Most photocatalytic and photovoltaic devices operate under broadband, constant illumination. Electron and hole dynamics in these devices, however, are usually measured using ultrafast pulsed lasers in a narrow wavelength range. In this work, we prove that steady-state, photomodulated X-ray spectra from a non-time-resolved synchrotron beamline can be used to estimate electron and hole distributions. A set of plasmonic metal core-shell nanoparticles is designed to systematically isolate photothermal, hot electron, and thermalized electron-hole pairs in a TiO2 shell. Steady-state changes in the Ti L2,3 edge are measured with and without continuous-wave illumination of the nanoparticle's localized surface plasmon resonance. Ab initio excited-state X-ray theory developed for transient X-ray measurements is then applied to model the experimental spectra in an attempt to extract the resultant steady-state carrier distributions. The results suggest that, within error, the quasi-equilibrium carrier distribution can be determined even from relatively noisy data with mixed excited-state phenomena.
format Preprint
id arxiv_https___arxiv_org_abs_2308_15771
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Determining Quasi-Equilibrium Electron and Hole Distributions of Plasmonic Photocatalysts using Photomodulated X-ray Absorption Spectroscopy
Palmer, Levi D.
Lee, Wonseok
Dong, Chung Li
Liu, Ru-Shi
Wu, Nianqiang
Cushing, Scott K.
Chemical Physics
Materials Science
Optics
Most photocatalytic and photovoltaic devices operate under broadband, constant illumination. Electron and hole dynamics in these devices, however, are usually measured using ultrafast pulsed lasers in a narrow wavelength range. In this work, we prove that steady-state, photomodulated X-ray spectra from a non-time-resolved synchrotron beamline can be used to estimate electron and hole distributions. A set of plasmonic metal core-shell nanoparticles is designed to systematically isolate photothermal, hot electron, and thermalized electron-hole pairs in a TiO2 shell. Steady-state changes in the Ti L2,3 edge are measured with and without continuous-wave illumination of the nanoparticle's localized surface plasmon resonance. Ab initio excited-state X-ray theory developed for transient X-ray measurements is then applied to model the experimental spectra in an attempt to extract the resultant steady-state carrier distributions. The results suggest that, within error, the quasi-equilibrium carrier distribution can be determined even from relatively noisy data with mixed excited-state phenomena.
title Determining Quasi-Equilibrium Electron and Hole Distributions of Plasmonic Photocatalysts using Photomodulated X-ray Absorption Spectroscopy
topic Chemical Physics
Materials Science
Optics
url https://arxiv.org/abs/2308.15771