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Electronic structure of lithium-doped anatase TiO2 prepared in ultrahigh vacuum

Richter, J H; Henningsson, A; Karlsson, P G; Andersson, M P; Uvdal, Per LU ; Siegbahn, H and Sandell, A (2005) In Physical Review B (Condensed Matter and Materials Physics) 71(23). p.1-235418
Abstract
Insertion of lithium in anatase TiO2, giving LixTiO2, is performed under ultrahigh vacuum (UHV) conditions and studied using synchrotron radiation based electron spectroscopy. Core level photoemission spectra are directly compared to results obtained after electrochemical insertion, illustrating the usefulness of the UHV approach. The growth of a state of mainly Ti 3d character in the band gap is monitored and the amount of charge transferred from Li to the band gap state is quantified. The result that the Ti 3d level is occupied by 0.85 +/- 0.10 electronic charge is in good agreement with theoretical predictions. Binding energy shifts of the core levels suggest that the population of the Ti 3d states does not follow a simple rigid band... (More)
Insertion of lithium in anatase TiO2, giving LixTiO2, is performed under ultrahigh vacuum (UHV) conditions and studied using synchrotron radiation based electron spectroscopy. Core level photoemission spectra are directly compared to results obtained after electrochemical insertion, illustrating the usefulness of the UHV approach. The growth of a state of mainly Ti 3d character in the band gap is monitored and the amount of charge transferred from Li to the band gap state is quantified. The result that the Ti 3d level is occupied by 0.85 +/- 0.10 electronic charge is in good agreement with theoretical predictions. Binding energy shifts of the core levels suggest that the population of the Ti 3d states does not follow a simple rigid band behavior. It is concluded that the formation of the Li-poor phase (x < 2%) is associated with pinning of the Fermi level to the bottom of the conduction band. The Li-poor phase can therefore be envisaged as related to defects. Changes in the valence photoemission spectrum and O 1s x-ray absorption spectrum are interpreted in terms of a decreased O 2p-Ti 3d interaction upon Li insertion. Shifts in the sample work function are finally found to agree reasonably well with the measured cell voltage for electrochemical Li insertion into a nanoporous anatase film. (Less)
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organization
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type
Contribution to journal
publication status
published
subject
in
Physical Review B (Condensed Matter and Materials Physics)
volume
71
issue
23
pages
1 - 235418
publisher
American Physical Society
external identifiers
  • wos:000230276800107
  • scopus:28344450835
ISSN
1098-0121
DOI
10.1103/PhysRevB.71.235418
language
English
LU publication?
yes
id
96814c71-90b6-473c-8659-9b99835958e0 (old id 151881)
date added to LUP
2007-07-03 16:21:38
date last changed
2017-07-30 04:33:21
@article{96814c71-90b6-473c-8659-9b99835958e0,
  abstract     = {Insertion of lithium in anatase TiO2, giving LixTiO2, is performed under ultrahigh vacuum (UHV) conditions and studied using synchrotron radiation based electron spectroscopy. Core level photoemission spectra are directly compared to results obtained after electrochemical insertion, illustrating the usefulness of the UHV approach. The growth of a state of mainly Ti 3d character in the band gap is monitored and the amount of charge transferred from Li to the band gap state is quantified. The result that the Ti 3d level is occupied by 0.85 +/- 0.10 electronic charge is in good agreement with theoretical predictions. Binding energy shifts of the core levels suggest that the population of the Ti 3d states does not follow a simple rigid band behavior. It is concluded that the formation of the Li-poor phase (x &lt; 2%) is associated with pinning of the Fermi level to the bottom of the conduction band. The Li-poor phase can therefore be envisaged as related to defects. Changes in the valence photoemission spectrum and O 1s x-ray absorption spectrum are interpreted in terms of a decreased O 2p-Ti 3d interaction upon Li insertion. Shifts in the sample work function are finally found to agree reasonably well with the measured cell voltage for electrochemical Li insertion into a nanoporous anatase film.},
  author       = {Richter, J H and Henningsson, A and Karlsson, P G and Andersson, M P and Uvdal, Per and Siegbahn, H and Sandell, A},
  issn         = {1098-0121},
  language     = {eng},
  number       = {23},
  pages        = {1--235418},
  publisher    = {American Physical Society},
  series       = {Physical Review B (Condensed Matter and Materials Physics)},
  title        = {Electronic structure of lithium-doped anatase TiO2 prepared in ultrahigh vacuum},
  url          = {http://dx.doi.org/10.1103/PhysRevB.71.235418},
  volume       = {71},
  year         = {2005},
}