Synthesis and luminescence properties of novel red-emitting Eu3+ ions doped silicate phosphors for photonic applications

Abstract

In the present work, we report on luminescence properties of Eu3+ ions doped KBaScSi3O9 silicate phosphors (KBSS) synthesized by high temperature solid state reaction method and the prepared phosphor samples were characterized through XRD, FE-SEM, photoluminescence and decay spectral measurements. The XRD pattern confirmed that the KBSS host lattice exhibited a monoclinic crystal structure. Room temperature photoluminescence (PL) spectroscopic results reveal that, on Eu3+ ion doping in the KBSS host matrix, the magnetic dipole transition (5D0 → 7F1) at 593 nm responsible for orange light, dominates the red emission with respect to the electric dipole transition (5D0 → 7F2) at 611 nm. The Judd-Ofelt (JO) intensity parameters Ωλ (λ = 2 and 4) have been calculated from the emission spectra to understand the nature of ligand environment around the Eu3+ ions. The radiative parameters, such as transition probability (A), stimulated emission cross-section (σPE), radiative lifetime (τR) and branching ratios (βR) corresponding to the 5D0→7F0, 5D0→7F1, 5D0→7F2, 5D0→7F3 and 5D0→7F4 emission transitions have been determined by using JO parameters and the refractive indices respectively. The concentration quenching effect for Eu3+ was found at the optimum doping concentration of 7 mol %. The CIE chromaticity coordinates were calculated from the luminescence spectra to explore the dominant emission colour of the title phosphors. The experimental lifetime values of 5D0 level of the Eu3+ doped silicate phosphors have been calculated and the obtained results were discussed in detail.