Rare Earth (Ce³⁺, Dy³⁺, Eu³⁺, and Tb³⁺ ) Doped Titanate : Photoluminescence Study

Abstract

A series of rare earth (RE³⁺) doped titanate phosphors based on BaTiO₃, SrTiO₃, and CaTiO₃ were synthesized via high-temperature solid-state reaction. Ce³⁺, Dy³⁺, Eu³⁺, and Tb³⁺ ions were introduced individually and in combination to explore their luminescence behavior and potential for white light emission. X-ray diffraction confirmed phase-pure perovskite structures in all samples.

Photoluminescence (PL) spectra exhibited characteristic emissions corresponding to 5d → 4f (Ce³⁺) and intra4f (Dy³⁺, Eu³⁺, Tb³⁺) transitions. The dopant ions were found to occupy lowsymmetry sites, as indicated by spectral asymmetry and intensity ratios. Luminescence decay measurements showed lifetimes consistent with the nature of the transitionsshort for Ce³⁺ and long for Eu³⁺, Dy³⁺, and Tb³⁺. Comparisons with commercial phosphors (Y₂O₃:Eu³⁺ and LaPO₄:Ce³⁺,Tb³⁺) demonstrated favorable color purity despite lower PL intensity.

To achieve white light emission, triple-doped compositions were optimized. The bestperforming system (Eu: 0.25 mol%, Dy: 0.40 mol%, Tb: 0.35 mol%) exhibited CIE chromaticity coordinates close to the white point (x = 0.355, y = 0.392), indicating effective spectral blending. These results suggest that RE-doped titanates are viable candidates for single-phase white light phosphors in solid-state lighting applications.