Preparation And Upconversion Luminescence Properties Of Er³⁺/Tb³⁺/Yb³⁺doped Bismuth Sodium Molybdate Glass Ceramics

Rare earth ion doped upconversion optical materials have a wide range of applications in solid-state lasers,deep-sea exploration,medicine and other fields.Transparent glass ceramics containing Na Bi（Mo O₄）₂crystal phase have stable properties at high temperature and are considered as good luminescent matrix materials.In this thesis,transparent glass ceramics with different Si O₂contents were prepared by melting method combined with heat treatment system.The effect of material composition on Na Bi（Mo O₄）₂microcrystalline structure and properties was studied by differential scanning calorimetry（DSC）,X-ray diffraction（XRD）,scanning electron microscopy（SEM）,density and microhardness.The optimum Si O₂content was 32%.A series of Er³⁺/Yb³⁺and Tb³⁺/Yb³⁺co-doped transparent glass ceramics were prepared by external doping of rare earth ions.The optimal heat treatment system was determined to be 620℃for 40 min and 620℃for 60 min,and the transmittance in the visible light range was above 75%and about 85%,respectively.The upconversion spectra of precursor glass and glass ceramics were measured and analyzed at 980 nm excitation.The position of emission peak and the transition of rare earth ions are discussed by upconversion spectrum.According to the upconversion emission peak changes of different doping concentrations,the cause of concentration quenching is analyzed by theoretical calculation as electric multipole interaction.And the optimal doping concentration of Er³⁺/Yb³⁺and Tb³⁺/Yb³⁺was determined to be 0.6%Er³⁺/1.0%Yb³⁺and 0.8%Tb³⁺/0.6%Yb³⁺,respectively.According to the relationship between pump power and emission intensity,the mechanism of up-conversion luminescence and energy transfer between rare earth ions were studied.The up-conversion processes of Er³⁺/Yb³⁺and Tb³⁺/Yb³⁺are two-photon processes.The chromaticity coordinates of 0.6%Er³⁺/1.0%Yb³⁺and 0.8%Tb³⁺/0.6%Yb³⁺co-doped transparent glass ceramics calculated by CIE software are all in the green light region.The results show that Er³⁺/Yb³⁺and Tb³⁺/Yb³⁺co-doped glass ceramics have potential applications in green upconversion lasers and photodynamic therapy.