Structure, surface analysis, photoluminescent properties and decay characteristics of Tb³⁺-Eu³⁺ co-activated Sr₂MgSi₂O₇ phosphor

Graphical abstract: - Highlights: • The successful combustion synthesis of mixed silicates. • Blue emission from Tb3+ by controlling doping concentration. • Tuneable and white emission from Tb-Eu co-doped system. - Abstract: Tb³⁺-Eu³⁺ co-activated Sr₂MgSi₂O₇ powder phosphors were synthesized by a solid-state reaction method. The structure, stretching vibrations, chemical and electronic states, and photoluminescent properties were studied using X-ray powder diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Time-of-flight secondary ion mass spectrometer (TOF-SIMS) and Photoluminescence (PL) spectroscopy respectively. The XRD pattern of the Sr₂MgSi₂O₇:Eu³⁺, Tb³⁺ phosphor resembles the standard tetragonal phase of Sr₂MgSi₂O₇. The fitted XPS data demonstrated that there were two different Sr²⁺ sites in the host lattice and a site occupied by Mg⁺ cations which connects the Sr⁺ sites with the Si⁺ ions. The TOF-SIMS results demonstrated localization and distribution of various ions within the host lattice (Sr₂MgSiO₇) including the Tb³⁺ and Eu³⁺ dopants. The photoluminescence of Tb³⁺ single doped Sr₂MgSi₂O₇ shown to emit blue and green emissions simultaneously with green emission more intense and the blue emission improving considerably when lower concentrations of Tb³⁺ were used. Only red emission was observed from the Eu³⁺ single doped Sr₂MgSi₂O₇. Upon Tb³⁺-Eu³⁺ co-doping, simultaneous emissions of blue, green and red lines were observed resulting in white emission.