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Title: Photoexcited Small Polaron Formation in Goethite (α-FeOOH) Nanorods Probed by Transient Extreme Ultraviolet Spectroscopy

Journal Article · · Journal of Physical Chemistry Letters

Small polaron formation limits the mobility and lifetimes of photoexcited carriers in metal oxides. As the ligand field strength increases, the carrier mobility decreases, but the effect on the photoexcited small polaron formation is still unknown. Extreme ultraviolet transient absorption spectroscopy is employed to measure small polaron formation rates and probabilities in goethite (α-FeOOH) crystalline nanorods at pump photon energies from 2.2 to 3.1 eV. The measured polaron formation time increases with excitation photon energy from 70 ± 10 fs at 2.2 eV to 350 ± 30 fs at 2.6 eV, whereas the polaron formation probability (85 ± 10%) remains constant. By comparison to hematite (α-Fe2O3), an oxide analogue, the role of ligand composition and metal center density in small polaron formation time is discussed. Here, this work suggests that incorporating small changes in ligands and crystal structure could enable the control of photoexcited small polaron formation in metal oxides.

Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
Grant/Contract Number:
AC02-05CH11231
OSTI ID:
1530368
Journal Information:
Journal of Physical Chemistry Letters, Vol. 9, Issue 14; ISSN 1948-7185
Publisher:
American Chemical SocietyCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 21 works
Citation information provided by
Web of Science

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Cited By (4)

Synthesis and Characterization of Ti-Fe Oxide Nanomaterials for Lead Removal journal November 2018
In situ observation of picosecond polaron self-localisation in α-Fe2O3 photoelectrochemical cells journal September 2019
Transient absorption spectroscopy using high harmonic generation: a review of ultrafast X-ray dynamics in molecules and solids
  • Geneaux, Romain; Marroux, Hugo J. B.; Guggenmos, Alexander
  • Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 377, Issue 2145 https://doi.org/10.1098/rsta.2017.0463
journal April 2019
Controlling polaron formation at hematite surfaces by molecular functionalization probed by XUV reflection-absorption spectroscopy journal September 2019

Figures / Tables (3)