Energetic, electronic and optical properties of lanthanide doped TiO{sub 2}: An ab initio LDA+U study

Substitutional energies, thermodynamic charge transition levels and optical properties of lanthanide doped anatase TiO{sub 2} has been investigated using local density approximation with the Hubbard U correction (LDA+U) within the density functional theory formalism. All the lanthanides apart from L...

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Bibliographic Details
Published in:Journal of solid state chemistry 2016-05, Vol.237
Main Authors: Mulwa, Winfred M., Ouma, Cecil N.M., Onani, Martin O., Dejene, Francis B.
Format: Article
Language:English
Subjects:
ABSORPTION
ABSORPTION SPECTRA
CRYSTAL STRUCTURE
CRYSTALS
DENSITY
DENSITY FUNCTIONAL METHOD
DOPED MATERIALS
EMISSION
INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY
IONS
OPTICAL PROPERTIES
PALLADIUM OXIDES
PHOTOCATALYSIS
RARE EARTHS
RUTILE
TITANIUM OXIDES
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Summary:Substitutional energies, thermodynamic charge transition levels and optical properties of lanthanide doped anatase TiO{sub 2} has been investigated using local density approximation with the Hubbard U correction (LDA+U) within the density functional theory formalism. All the lanthanides apart from La introduced impurity states in the host band gap on doping. The calculated substitutional energies indicate that it is possible to dope TiO{sub 2} with lanthanide ions. The optimal doping percentage was predicted to be ~3% and dopant levels resulting from Ce, Nd, Sm, Gd and Tm doping were found to possess negative U characteristics. In addition the calculated thermodynamic transition levels predicted Lu as not having any possible charge transitions within the host band gap. The calculated optical absorption coefficients indicate that lanthanide doping led to optical absorption in the visible regime. - Graphical abstract: Crystal structure of doped Sm doped TiO{sub 2} (RHS). Calculated PDOS and absorption spectra of Sm doped TiO{sub 2}. - Highlights: • Lanthanide doping significantly improved the optical properties of anatase TiO{sub 2}. • Lanthanide doping led to emission in the visible regions of the optical spectrum. • La, Ce, Pm, Sm, Eu, Gd, Tm, Yb and Lu doping gave good photocatalytic properties. • The optimum doping concentration in anatase TiO{sub 2} was found to be 2.78%.
ISSN:0022-4596
1095-726X
DOI:10.1016/J.JSSC.2016.02.003