Enhancement of the photoluminescence and long afterglow properties of Ca₂MgSi₂O₇:Eu²⁺ phosphor by Dy³⁺ co-doping

Abstract

The Ca₂MgSi₂O₇:Eu²⁺ and Ca₂MgSi₂O₇:Eu²⁺, Dy³⁺ long afterglow phosphors were synthesized under a weak reducing atmosphere by the traditional high temperature solid state reaction method. The synthesized phosphors were characterized by powder X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX) techniques. The luminescence properties were investigated using thermoluminescence (TL), photoluminescence (PL), long afterglow, mechanoluminescence (ML), and ML spectra techniques. The crystal structure of sintered phosphors was an akermanite type structure, which belongs to the tetragonal crystallography. TL properties of these phosphors were investigated, and the results were also compared. Under the ultraviolet excitation, the emission spectra of both prepared phosphors were composed of a broad band peaking at 535 nm, belonging to the broad emission band. When the Ca₂MgSi₂O₇:Eu²⁺ phosphor is co-doped with Dy³⁺, the PL, afterglow and ML intensity is strongly enhanced. The decay graph indicates that both the sintered phosphors contain fast decay and slow decay process. The ML intensities of Ca₂MgSi₂O₇:Eu²⁺ and Ca₂MgSi₂O₇:Eu²⁺, Dy³⁺ phosphors were proportionally increased with the increase of impact velocity, which suggests that this phosphor can be used as sensors to detect the stress of an object.