Facile molten salt synthesis, structural, morphological and optical studies of ASiO3: Eu2+, Er3+ (A = Ca, Ba, Sr) perovskites

Abstract

This work reports structural, morphological and optical studies of alkaline earth metasilicates ASiO3: Eu2+, Er3+ (A = Ca, Ba, Sr) perovskites synthesized by the facile molten salt synthesis technique. Using the molten chloride salt, NaCl to create an active reaction medium, the phosphors with doping concentration of Eu2+ and Er3+ ions varying from 0 to 2 at.% were synthesized at sintering temperature of 950 °C. The crystallographic analysis done by PXRD confirms the crystalline nature, homogeneity and phase purity of synthesized perovskites. The FESEM and TEM micrographs show the distinct morphology and uniform grain connectivity of the particles. The FTIR spectroscopy set forth the finger print of the molecular activities of the constituent elements of the synthesized phosphors. The optical studies done by PL spectroscopy show distinct emissions of synthesized phosphors with enhanced quantum yields over a wide spectral region resulting from the hypersensitive transitions 2P3/2–4I15/2, 4G7/2–4I15/2, 4G11/2–4I15/2, 4H9/2–4I15/2, 2P3/2–4I11/2 and 4F7/2–4I15/2 of Er3+ ions and crystal field splitting influenced 4f–5d transitions of Eu2+ ions. These emissions confirm the important characteristic of color tunability of the phosphors. The dipole–dipole interaction between rare earth ions crucially amend the optical behavior of synthesized phosphors giving rise to distinct spectroscopic characteristics and enhanced lumen output of the synthesized ASiO3:Eu2+, Er3+(A = Ca, Ba, Sr) perovskites.