Preparation And Luminescence Properties Of Rare Earth Doped Gadolinium Molybdate Salt Glass Ceramics

In this thesis,a series of Sm³⁺:SrGd₂（Mo O₄）₄ glass-ceramics,Tb³⁺:SrGd₂（Mo O₄）₄ glass-ceramics,and(Tb³⁺-Sm³⁺):SrGd₂（Mo O₄）₄ glass-ceramics samples were prepared by melt crystallization method.The Sm³⁺:SrGd₂（Mo O₄）₄ glass-ceramic samples,Tb³⁺:SrGd₂（Mo O₄）₄ glass-ceramic samples,and(Tb³⁺-Sm³⁺):SrGd₂（Mo O₄）₄ glass-ceramic samples were characterized by differential thermal analysis,X-ray diffraction,scanning electron microscopy,and light transmittance curves,respectively.The appropriate heat treatment conditions were determined to be 640℃,2 h,630℃,2 h,and 640℃,2 h.At the same time,the transmittance of three rare earth doped SrGd₂（Mo O₄）₄ glass ceramic samples was measured to be 80%,80.8%,and 74%,respectively.By comparing the SEM photos of the three groups of samples,it was found that the grain distribution in the glass ceramic under suitable heat treatment conditions was uniform.Through the intensity analysis of excitation and emission spectra of Sm³⁺:SrGd₂（Mo O₄）₄ glass ceramics,Tb³⁺:SrGd₂（Mo O₄）₄ glass-ceramics glass ceramics,and(Tb³⁺-Sm³⁺):SrGd₂（Mo O₄）₄ glass ceramics samples with different concentrations,the appropriate doping concentrations for Sm³⁺single-doped samples,Tb³⁺single-doped samples,and Tb³⁺-Sm³⁺co-doped samples were determined to be 0.4%Sm³⁺,0.4%Tb³⁺,and0.4%Tb³⁺-0.5%Sm³⁺,respectively.As the concentration of rare earth ions increases,concentration quenching occurs in glass ceramic samples doped with rare earth ions.According to the calculation results of critical distance,it is analyzed that concentration quenching is caused by electrical multi-stage interactions.The calculation shows that the fluorescence lifetime of Sm³⁺single-doped samples,Tb³⁺single-doped samples,and Tb³⁺-Sm³⁺co-doped samples at appropriate doping concentrationsτ2.6372 ms,2.7121 ms,and2.4088 ms,respectively.By analyzing the emission spectra of Tb³⁺-Sm³⁺co-doped samples,it was found that there was energy transfer between Tb³⁺and Sm³⁺,and the energy transfer efficiency between Tb³⁺and Sm³⁺was calculated.Through further analysis,it is known that the energy transfer of Tb³⁺→Sm³⁺is the result of dipole even order interaction.The calculation of chromaticity coordinates shows that the optimal chromaticity coordinates are（0.3156,0.3481）,completing the movement of the green light area to the white light area.