Luminescence of Sm³⁺ Ions Sensitized by a TiO₂ Matrix

Ti_1-xSm_xO_2-x/2 (x = 0.025, 0.05, and 0.1) solid solutions with the anatase structure were synthesized by the precursor method and characterized by x-ray diffraction and scanning electron microscopy. Titanium glycolate Ti(OCH₂CH₂O)₂ in which Ti was partially replaced by Sm was used as the precursor. The Ti_1-xSm_xO_2-x/2 solid solutions exhibited intense reddish-orange luminescence at room temperature upon excitation at 350 nm. The luminescence properties of the compounds were due to f⁵-intraconfigurational transitions of Sm. The highest luminescence intensity was achieved for Ti_1-xSm_xO_2-x/2 with x = 0.05. The chromaticity coordinates and correlated color temperature values were close to those typical of red phosphors.