Luminescent properties of R⁺ doped Sr₂MgSi₂O₇:Eu³⁺ (R⁺ = Li⁺, Na⁺ and K⁺) orange–red emitting phosphors

Abstract

Sr₂MgSi₂O₇:Eu³⁺ and Sr₂MgSi₂O₇:Eu³⁺, R⁺ (R⁺ = Li⁺, Na⁺ and K⁺) phosphors were prepared by conventional solid state reaction method. The crystal structures of synthesized phosphors were an akermanite type structure which belongs to the tetragonal crystallography. The thermoluminescence kinetic parameters such as activation energy, order of kinetics and frequency factor was calculated by peak shape method. In this work, the orange-red emission originated from the ⁵D₀–⁷F_J (J = 0, 1, 2, 3, 4) transitions of Eu³⁺ ions could clearly be observed after samples were excited at 395 nm. Decay graph indicate that these phosphors also contain the fast and slow decay process. Mechanoluminescence intensity of prepared Sr₂MgSi₂O₇:Eu³⁺ and Sr₂MgSi₂O₇:Eu³⁺, R⁺ (R⁺ = Li⁺, Na⁺ and K⁺) phosphors were increases linearly with the increasing impact velocity of moving piston (load). CIE color chromaticity diagram confirm that the prepared phosphors would emit orange-red color. Thus the present investigation indicating that this phosphor may be a potential candidate for stress sensors. The dopant R⁺ (R⁺ = Li⁺, Na⁺ and K⁺) as charge compensator in Sr₂MgSi₂O₇:Eu³⁺ can further enhance luminescence intensity, and the emission intensity of Sr₂MgSi₂O₇:Eu³⁺ doping Li⁺ is higher than that of Na⁺ or K⁺.