Photoluminescence decay curve analysis of some rare earth doped CeO₂ phosphors

Abstract

CeO₂:M (Eu³⁺, Er³⁺ and Dy³⁺) phosphors were synthesized by modified solid-state reaction technique at variable concentrations of Eu³⁺, Er³⁺ and Dy³⁺. This technique is suitable for large-scale production and it is less time-consuming. The prepared samples were characterized by X-ray diffraction (XRD) technique, scanning electron microscopy (SEM), and Photoluminescence (PL) decay curve analysis. XRD patterns of the prepared samples confirm the cubic fluorite crystal structure of all phosphors. Crystallite size was calculated by using well known Scherer’s formula. SEM images express good surface morphology with nanoflower like shape. Comparative studies of photoluminescence decay curves of CeO₂:M (Eu³⁺, Er³⁺ and Dy³⁺) with different concentrations of dopant have been done. Decay constants for all prepared phosphors were calculated by curve fitting technique. Samples were excited under UV radiation for few nanoseconds at room temperature. The PL decay curves were measured for ⁵D₀→⁷F₁ transition of CeO₂:Eu³⁺,⁴S_3/2→⁴I_15/2 transition of CeO₂:Er³⁺ and ⁴F_9/2→⁶H_13/2 transition of CeO₂:Dy³⁺ phosphors. Decay curve for CeO₂:Eu³⁺ (1.5 mol%) phosphor shows optimum concentration with higher intensity of photoluminescence signals and comparatively higher decay constants.