Electronic structure of lithium-doped anatase TiO{sub 2} prepared in ultrahigh vacuum

Journal Article · Wed Jun 15 04:00:00 EDT 2005 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PhysRevB.71.235418· OSTI ID:20719063

Richter, J H; Henningsson, A; Karlsson, P G; Siegbahn, H; Sandell, A ^[1]; Andersson, M P; Uvdal, P ^[2]

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1. Department of Physics, Uppsala University, P.O. Box 530, S-751 21 Uppsala (Sweden)
2. Chemical Physics, Department of Chemistry, Lund University, P.O. Box 124, S-221 00 Lund (Sweden)

Insertion of lithium in anatase TiO{sub 2}, giving Li{sub x}TiO{sub 2}, 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.

• OSTI ID: 20719063
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 23 Vol. 71; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION SPECTRA
BINDING ENERGY
CHARGE EXCHANGE
DOPED MATERIALS
ELECTRIC POTENTIAL
ELECTROCHEMISTRY
ELECTRONIC STRUCTURE
ENERGY GAP
FERMI LEVEL
LITHIUM ADDITIONS
NANOSTRUCTURES
PHOTOELECTRON SPECTROSCOPY
PHOTOEMISSION
POROUS MATERIALS
SYNCHROTRON RADIATION
THIN FILMS
TITANIUM OXIDES
VALENCE
WORK FUNCTIONS
X RADIATION