Nb5+:Eu3+-codoped TiO2 nanopowders for chemical composition adjustment have been synthesized via Ar/O2 radio-frequency thermal plasma. X-ray diffraction (XRD) results reveal that all the resultant powders exhibited mixture polymorphs of anatase (mean size: ∼45 nm) as the major phase and rutile (mean size: ∼71 nm). Rutile formation was promoted by the Eu3+ doping but suppressed by the Nb5+ addition. Combined observation using FE-SEM and TEM indicates that all the plasma-synthesized powders had a majority of facet-shaped particles (several nanometers) and a small proportion of nearly spherical crystals (∼150 nm). For the defect-mediated photoluminescence (PL) emission through the energy transfer from the TiO2 host to the Eu3+ activator, the PL intensity originating from the 5D0 → 7F2 electronic transition weakened but that from the 5D0 → 7F1 electronic transition strengthened with increasing Nb5+ content. This may be a result of the decrease in the oxygen vacancy defects in the TiO2 host lattice, as revealed by the joint means of UV-vis absorption spectra and excitation and emission spectra.
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry