RESUMO
Europium doped KCaF3 phosphors (KCaF3:Eu3+) were prepared using various concentrations of Eu3+ by conventional solid-state reaction process. The X-ray diffraction (XRD) studies confirmed the formation of orthorhombic structured KCaF3:Eu3+ phosphors. Scanning Electron Microscopy (SEM) image of the synthesized phosphor exhibits agglomerated particles with irregular shapes. The composition of the synthesized sample was determined by Energy Dispersive Spectroscopy (EDS) spectrum and elemental mapping showed the homogeneous dispersion of Eu3+ ions into the synthesized KCaF3:Eu3+ phosphor. The emission peak intensity at 594 nm from photoluminescence (PL) spectra was found to increase with the increase of Eu3+ concentrations from 0.02 mol% to 0.06 mol% and decreased with the further increase of Eu3+ concentration up to 0.1 mol%. CIE1931 chromaticity diagram coordinates (x, y) of KCaF3:(0.06 mol%) Eu3+ phosphors were positioned in the reddish-orange region (x = 0.5736, y = 0.4224). Photoluminescence property confirms the suitability of KCaF3:Eu3+ phosphors for Solid state lighting application. X-ray induced luminescence (radioluminescence, RL) is recorded for KCaF3:Eu3+ phosphors showing the characteristic emission of Eu2+ and Eu3+. ESR study on KCaF3:Eu3+ phosphors confirm the presence of Eu2+ ions. Beta irradiated thermoluminescence (TL) glow curve of Eu3+ doped KCaF3 phosphors is measured and deconvoluted using Gaussian fitting. TL kinetic parameters like activation energy (Ea) and frequency factor (s) are calculated for all the deconvoluted peaks using peak shape method which shows the synthesized KCaF3:Eu3+ phosphors is suitable for dosimetry application.
