Effect of light conversion agent on luminous properties of a new down-converting material SrAl_2O_4:Eu^(2+),Dy^(3+)/light conversion agent

A new luminous material SrAl2O4：Eu^2＋,Dy^3＋/light conversion agent that can emit red light in the darkness after being excited was fabricated by combining light conversion agent on to SrAl2O4：Eu^2＋,Dy^3＋ particles through YsiX3.The morphology of the luminous materials was analyzed by scan electron microscopy（SEM）.The emission behavior was evaluated by fluorescence spectrophotometric analysis and the results demonstrated that the emission spectra of samples had a redshift compared to SrAl2O4：Eu^2＋,Dy^3＋ and the emission intensity rose dramatically at first and then decreased when the ratio of light conversion agent doping was over 1.4 wt.%.And the emission color of SrAl2O4：Eu^2＋,Dy^3＋/light conversion agent was tuned from green（SrAl2O4：Eu^2＋,Dy^3＋）to orange-red.Furthermore,the afterglow property was also investigated,and the results indicated that the afterglow brightness reached 6.5 cd/m^2,and as the light conversion agent concentration increased the brightness intensity decreased.

Luminescence properties of composite material Sr_(2)MgSi_(2)O_(7):Eu^(2+),Dy^(3+)/light conversion agent with multilayer structure

In order to improve the red luminescent properties,Sr_(2)MgSi_(2)O_(7):Eu^(2+),Dy^(3+)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 Sr_(2)MgSi_(2)O_(7):Eu^(2+),Dy^(3+)/light conversion agent(SMED/LCA)was fabricated with light conversion agent and Sr_(2)MgSi_(2)O_(7):Eu^(2+),Dy^(3+)at a certain mass ratio.SiO_(2)(Al2 O_(3) 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.SiO_(2),Al_(2)O_(3) and MgF_(2) 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/m^(2) and the afterglow color purity calculated from CIE color coordinates is basically unchanged.

Luminescence properties of SrB_4_O_7:Sm^(2+) for light conversion agent

A deep red-emitting SrB407：Sm^2＋ phosphor for light conversion agent was synthesized by the conventional solid-state reaction. X-ray powder diffraction （XRD） analysis confirmed the phase formation of SrB4OT：Sm^2＋ materials. Results of luminescence properties showed that the phosphor could be efficiently excited by the UV-vis light region from 250-500 nm, and it exhibited deep red （685 nm） emis- sion corresponding to ^5D0→^7F0 transition of Sm^2＋. The critical quenching concentration of Sm^2＋ in SrB407：Sm^2＋ phosphor was about 0.05, and the corresponding concentration quenching mechanism was verified to be the dipole-dipole interaction according to the Dexter＇s theory. The decay times had few alterations with different concentrations in SrB4OT：xZm^2＋ phosphor.