Synthesis And Luminescence Performance Of A₃ZrF₇:Yb/Er(A=Na⁺,K⁺ And NH₄⁺)

Upconversion luminescent material refers to an unconventional material that can absorb low energy long wavelength radiation into high energy short wavelength radiation.Rare earth doped upconversion luminescence materials have potential applications in lighting,3D display,solar cells,biological imaging,bio-labeling and photodynamic therapy due to their advantages of low phonon energy,narrow emission band,high color purity,low toxicity,large tissue penetration depth and low background interference.Therefore,people have great interest in the study of rare earth doped upconversion luminescent materials.Although transformation on rare earth luminescence materials have many advantages and has potential applications in many aspects,but this kind of material that commonly encountered in synthetic material luminous intensity weak problem,greatly restrict the practical application of materials,according to this problem the researchers have proposed many methods to enhance the strength of material conversion luminescence,These methods can be summarized as the introduction of non-lanthanide ions,the doping of precious metals,changing the concentration of matrix materials and doped ions,and the construction of core-shell structures on the surface of materials,etc.It is significant to enrich the types of upconversion luminescence by changing the matrix materials.However,for the rare earth upconversion luminescent materials,the main body of the luminescent materials is the matrix material,which generally does not constitute the luminescent energy level,and is mainly the material that provides the appropriate crystal field for the luminescent center.In addition,the matrix materials need to have low phonon energy,high mechanical strength and chemical stability.In this paper,rare earth compound fluoride Na₃Zr F₇,K₃Zr F₇ and(NH₄)₃Zr F₇ were synthesized as matrix materials,Yb³⁺as sensitizer and Er³⁺as activator.The influence of the reaction conditions on the crystal shape,size and morphology of the prepared matrix materials was studied,and the influence on the luminescence properties was discussed.The main research contents of this paper are as follows:(1)Tetragonic Na₃Zr F₇:Yb/Er upconversion luminescent materials were synthesized by simple and environmental friendly solvothermal method in OA and ODE solvent systems by adjusting the amount of Na F reactants,reaction time,reaction temperature,rare earth doping amount and other reaction conditions.Their effects on the crystal phase,size and morphology of Na₃Zr F₇ were studied,and their effects on the luminescence properties were discussed.The results show that,The luminescent material Na₃Zr F₇ was prepared under the conditions of 5mmol Na F,the reaction temperature was 220°C,the volume ratio of OA to ODE was 30:15,the doping concentration of rare earth ion Yb³⁺was20%,the doping concentration of rare earth ion Er³⁺was 2.6%and the reaction time was 72 h.The luminescent material Na₃Zr F₇ has good luminescence and up-conversion red emission.(2)By adjusting the amount of KF and KOH reactants,reaction time,reaction temperature,rare earth doping amount and other reaction conditions,the cubic phase K₃Zr F₇:Yb/Er upconversion luminescent materials were synthesized by simple and environmental friendly solvothermal method in a solvent composed of OA and HA system.Their effects on the crystal phase,size and morphology of upconversion luminescent material K₃Zr F₇ were studied,and their effects on luminescent properties were also discussed.The results show that,The dosage of KF was 8 mmol and KOH was 16 mmol,the reaction temperature was 220°C,the volume ratio of OA to HA was 20:25,the doping concentration of rare earth ion Yb³⁺was 25%,the doping concentration of rare earth ion Er³⁺was 1.6%and the reaction time was48 h.The luminescent material K₃Zr F₇ has good luminescence upconversion green emission.(3)Cubic phase(NH₄)₃Zr F₇:Yb/Er upconversion luminescent materials were synthesized by simple and environmental friendly solvothermal method in OA and HA solvent systems.By adjusting the amount of NH₄F reactants,reaction time,reaction temperature,the doping amount of rare earth.In addition,their effects on the crystal phase and size of upconversion luminescent material(NH₄)₃Zr F₇ were studied,and their effects on luminescent properties were discussed.The results show that,When NH₄F dosage was 10 mmol,reaction temperature was220°C,volume ratio of OA to HA was 20:25,the doping concentration of rare earth ion Yb³⁺was 5%,the doping concentration of rare earth ion Er³⁺was 1.2%,and reaction time was 12 h,the luminescent material(NH₄)₃Zr F₇ has good luminescence upconversion red emission.