Synthesis and luminescence characterization of Sr(0.5)Ca(0.5)TiO3:Sm(3+) phosphor

The spectroscopic properties of trivalent samarium doped Sr0.5Ca0.5TiO3 perovskite phosphor material (Sr0.5Ca0.5TiO3:xSm(3+), x=0.05, 0.1, 0.5, 1, 1.5) synthesized by the solid state method have been studied. The X-Ray Diffraction profile confirms the orthorhombic perovskite Sr0.5Ca0.5TiO3 structure of the prepared samples. The SEM study reveals the surface morphology. The Judd-Ofelt intensity parameters were calculated for 0.5 wt% Sm(3+) doped Sr0.5Ca0.5TiO3. Transition probabilities, branching ratios and radiative lifetime were evaluated by using Judd-Ofelt analysis. The emission spectra under 405 nm excitation shows five emission peaks at 564 nm, 599 nm, 645 nm, 707 nm and 776 nm corresponding to the transitions (4)G5/2→(6)Hj (j=5/2, 7/2, 9/2, 11/2 and 13/2) respectively. The higher values of branching ratio and stimulated emission cross-section for (4)G5/2→(6)H7/2 transition of Sr0.5Ca0.5TiO3:0.5 wt% Sm(3+) shows its suitability in the field of visible lasers and optical fiber amplifiers. The experimental lifetimes of Sm(3+) doped samples were estimated using the decay curves corresponding to (4)G5/2→(6)H7/2 transition upon 405 nm excitation. Concentration dependence on emission intensity and experimental lifetime were also studied. From the CIE diagram we can see that as the concentration of Sm(3+) ions increases from 0.05 wt% to 1.5 wt% the CIE color co-ordinates changes from greenish yellow to yellowish orange.