Enhanced photoluminescence and thermal stability of divalent ions (Zn²⁺, Mg²⁺) assisted CaTiO₃:Eu³⁺ perovskite phosphors for lighting applications

Abstract

Current study proposes the improved red emission of Zn²⁺ and Mg²⁺ ions incorporated CaTiO₃:Eu³⁺ phosphors synthesized via the well-known solid-state reaction method. Under the 397 nm UV excitation, the Zn²⁺- and Mg²⁺-incorporated CaTiO₃:0.15Eu³⁺ phosphor having orthorhombic structure with space group Pbnm exhibited an intense red emission at 619 nm. This can be credited to the hypersensitive ⁵D₀ → ⁷F₂ transition of Eu³⁺ ions, which is also indicative of the fact that the Eu³⁺ ions populated the non-inversion symmetry sites in the CaTiO₃ lattices. The optimized composition CaTiO₃:0.15Eu³⁺, 0.20Zn²⁺ and CaTiO₃:0.15Eu³⁺, 0.10Mg²⁺ phosphors, pronounces in a magnificent enhancement of PL intensity by 5.5 and 2.5 times, respectively, as compared to CaTiO₃:0.15 Eu³⁺ phosphor. From the temperature-dependent emission spectra, ∆E_a were enunciated to be 0.101 and 0.086 eV for CaTiO₃:0.15Eu³⁺, 0.20Zn²⁺ and CaTiO₃:0.15Eu³⁺, 0.10Mg²⁺ phosphors, respectively, for thermal quenching. In addition, it can be better understood as related to the adequate thermal stability of 60% even at 450 and 420 K, respectively. Furthermore, the Judd–Ofelt theory was used to study the radiative intensity parameters of Eu³⁺ ions in the CaTiO₃ lattices. The experimental results incited the bright prospects of synthesized ceramics as a promising candidate for lighting applications.