Preparation and luminescence study of Eu(III) titanate nanotubes and nanowires using carbon nanotubes as removable templates

Preparation, characterization and photoluminescence properties of SiO2 and SiO2:Eu3+ submicron rods

“…12(b) were assigned to the f-f transition of the Eu 3 þ , due to the shielding of the 4f orbitals by the outer 5s 2 and 5p 6 orbitals. All observed peaks were exactly correspond to the metastable orbital singlet state 5 D 0 to spin-orbital states of 7 F J (J¼ 0, 1, 2, 3 and 4) of Eu 3 þ , which indicated the characteristic transitions from the 5 D 0 to 7 F 0 at 579 nm, 7 F 1 at 590 nm, 7 F 2 at 613 nm, 7 F 3 at 646 nm, and 7 F 4 at 699 nm [41], and the strongest peak was located at 613 nm, which was the characteristic peak of Eu 3 þ ions [42]. From these luminescence spectra we could find that the spectral were almost same irrespective of the Eu 3 þ concentration, but with the increasing of the Eu 3 þ concentration from 1 mol% to 9 mol%, the PL intensity of the 5 D 0 -7 F 2 transition increased at first, reaching a maximum value at the concentration of 9 mol%, and then decreased with the increasing of Eu 3 þ content due to the concentration quenching effect.…”

“…The luminescence of the Eu 3 þ doped into the silica framework was predominantly attributed to 5 D 0 -7 F 1 and 5 D 0 -7 F 2 , and the 5 D 0 -7 F 2 peak was dominant in comparison with other peaks, which was a hypersensitive forced electric dipole transition. It was known that the f-f transition arising from a forced electric dipole was forbidden and became partially allowed when the rare-earth ion was situated at a low symmetry site [42]. Therefore, the Eu 3 þ concentration as well as the silica framework structure affected the efficient luminescence of Eu 3 þ [24].…”

Electrospinning Synthesis and Photoluminescence Properties of One-Dimensional SiO<sub>2</sub>:Tb<sup>3+</sup> Nanofibers and Nanobelts

“…It could be indicated that the optimal doping concentration of Tb hypersensitive forced electric dipole transition. It was known that the f-f transition arising from a forced electric dipole was forbidden and became partially allowed when the rare-earth ion was situated at a low symmetry site [20]. Therefore, the Tb 3+ concentration as well as the silica framework structure affected the efficient luminescence of Tb 3+ ions [12].…”