Optical Behavior of CaSiO₃:Eu²⁺, Er³⁺, BaSiO₃:Eu²⁺, Er³⁺and SrSiO₃:Eu²⁺, Er³⁺ Phosphors

Abstract

The effect of Eu²⁺ and Er³⁺ ions on the optical characteristics of alkaline earth metasilicate perovskite synthesized via the solid-state reaction method was studied here. The ASiO₃ (A = Ca, Ba, Sr) phosphors activated with rare earth doping Eu²⁺ (0–2 mol.%) and Er³⁺ (0–2 mol.%) were subjected to structural, morphologic and spectroscopic studies in this work. The synthesized phosphors show a crystalline nature with appreciable phase purity and homogeneity in powder x-ray diffractometry (PXRD) analysis. The field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analyses showed interesting morphology and topography of the prepared phosphors. A comparative study of molecular activities of undoped and doped phosphors was done in Fourier-transform infrared (FTIR) spectroscopy. This revealed that the spectral behaviors of phosphors were strongly influenced by the impurity ions. The photoluminescent (PL) characteristics showed distinct sharp emissions in a wide spectral region of 300–500 nm under 275-nm excitation corresponding to hypersensitive transitions of Er³⁺ ions and crystal field-influenced 4f–5d transitions of Eu²⁺ ions. In the afterglow decay analysis of the synthesized phosphors, the luminescence lifetime varied from 11.7226 s to 13.1266 s, which confirms the occupation of shallow trapping sites by the excited electrons.