Optical behavior of Eu2+and Yb2+ doped alkaline earth metatitanate perovskite phosphors

Abstract

A complete investigation of optical and spectral behavior of Eu2+ and Yb2+ activated ATiO3 (A = Ca, Ba, Sr) alkaline earth metatitanates perovskites phosphors synthesized via conventional solid state reaction technique is done here. The crystallographic analysis show crystalline structure with high phase purity and homogeneity in the synthesized phosphors. The FESEM analysis shows formation of porous globular particles with irregular shape, uniform grain connectivity and variable dimensions in the synthesized phosphors. The TEM micrographs also confirm the irregularity of particle shape along with agglomeration. The functional group analyses done under FTIR spectroscopy set forth the fingerprints of various molecular activities in the phosphors. The PL emission spectra monitored at λ = 230 nm for CaTiO3 :Eu2+,Yb2+, λ = 227 nm for BaTiO3 :Eu2+,Yb2+ and λ = 225 nm for SrTiO3 :Eu2+,Yb2+ phosphors show distinct line emissions at 482 nm, 495 nm, 545 nm, 595 nm and 620 nm attributing to characteristic hypersensitive transitions of Eu2+ (4f-5d) and Yb2+ ions (5d-4f) ions. The chromaticity coordinates were computed and plotted in the two dimensional CIE gamut chart to study the color tunability of the synthesized phosphors. The enhancement in the optical emissions and improved quantum yields were studied in detail under photoluminescent spectroscopy.