Intense Photoluminescence Emission in Eu³⁺‐ and Dy³⁺‐ Doped Low‐Band Gap Perovskite Titanate, Na_0.5Gd_0.5TiO₃

Abstract

Na 0.5 Gd 0.5-x RE x TiO 3 (RE = Eu and Dy) phases with orthorhombic perovskite structure were synthesized by high temperature solid state reaction and the photoluminescence properties were investigated. The phase purity was confirmed by Rietveld refinement of the powder XRD patterns in Pnma space group. The band gap of the host was found to be 3.41 eV from UV/Vis diffuse reflectance spectrum. In the Eu 3 + doped phases, the 5 D 0 ! 7 F 2 electric dipole (ED) transition is predominant in the emission spectrum of Eu 3 + , under 397 nm excitation, and is in agreement with the non-centrosymmetric C s point group of the EuO 8 polyhedron. The critical concentration of the Eu 3 + was found to be x = 0.075 above which, concentration quenching occurs. Dy 3 + doping resulted in intense white light emission under 389 nm excitation.