Luminescence properties of composite material Sr2MgSi2O7:Eu2+,Dy3+/light conversion agent with multilayer structure

In order to improve the red luminescent properties, Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ was selected as a blue persistent luminescent donor phosphor, while light conversion agent was utilized to tune the persistent luminescent spectra from blue to red. Composite red luminescent material Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺/light conversion agent (SMED/LCA) was fabricated with light conversion agent and Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ at a certain mass ratio. SiO₂ (Al₂O₃ or MgF₂) were coated on the surface of SMED/LCA through heterogeneous deposition method. The structural and optical characteristics of the resulting samples were launched in terms of X-ray diffraction and emission spectrum as well as afterglow brightness. The results demonstrate that the emission spectrum exhibits two emission bands, and the peaks are located at around 470 and 615 nm. SiO₂, Al₂O₃ and MgF₂ are coated on the surface of SMED/LCA like a protective shell to maintain its stability and luminescent properties, the afterglow initial brightness is still up to 0.37 cd/m² and the afterglow color purity calculated from CIE color coordinates is basically unchanged.