Luminescence Performance And Anti-counterfeiting Of Rare Earth Ions Based On KY(CO₃)₂ Host

In recent years,rare earth luminescent materials have attracted much attention because of their rich luminous colors,stable chemical properties and strong light absorption capacity.Among rare earth luminescent materials,Tb³⁺and Eu³⁺are common rare earth ions for green and red light emission,respectively.As an excellent luminescence efficiency,abundant energy level and special emission spectrum,luminescent material can not only be used for lighting,but also for decoration and anti-counterfeiting and other fields.However,the common inorganic phosphor is white.The visible light transmittance is low for the poor invisible application.Nowadays,luminescent materials are mainly applicable to lighting.In this paper,a new KY(CO₃)₂luminescent host with good thermal stability,non-deliquetry and better light transmittance was proposed.And the luminescence performance of Ce³⁺,Tb³⁺,Eu³⁺rare earth ions and its application in anti-counterfeiting were studied.The main contents are as follows:1.Novel single phase Tb³⁺doped and Ce³⁺,Tb³⁺co-doped KY(CO₃)₂ rare earth luminescent materials were prepared by hydrothermal method,and the mechanisms of Tb³⁺green light emission enhancement were studied.The crystal structure,thermal stability and spectra properties of materials were examined by XRD,thermal differential thermal curves and fluorescence spectra,respectively.The results show that the thermal stability of KY(CO₃)₂ host is good,and the thermal decomposition temperature is about 451°C.Y³⁺can be substituted by the rare earth ions Ce³⁺and Tb³⁺in the lattice to form a stable compound.The green light emission of Tb³⁺ions can be effectively enhanced by increasing the doping concentration of Tb³⁺ions and Ce³⁺sensitization.When the concentration of Tb³⁺ions in KY(CO₃)₂:Tb³⁺increased by 10times,the green light emission intensity at 543 nm can be effectively enhanced by 29.7times.When Ce³⁺ions are used as sensitized ions,the green light emission intensity at543 nm can be enhanced by 12.5 times.2.A new single phase Tb³⁺,Eu³⁺doped KY(CO₃)₂ rare earth luminescent material was prepared by hydrothermal method to study the multicolor luminescence performance of phosphors The results show that Tb³⁺and Eu³⁺can be well dissolved in KY(CO₃)₂ lattice to form a solid solution.There is an energy transfer between Tb³⁺and Eu³⁺of the solid solution.When the different wavelengths of excitation light are used,the luminescent ions can be selectively excited with different luminescent colors.Even if the excitation wavelength is constant,multicolor luminescence of the material can also be achieved by adjusting the ratio of Tb³⁺to Eu³⁺.3.The application on the anti-counterfeiting was investigated by multi-color luminescence material.Three technical method are as follows:Firstly,the special excitation wavelength of Tb³⁺and Eu³⁺ions could be utilized to achieve single wavelength anti-counterfeiting.Secondly,the difference of Tb³⁺/Eu³⁺concentration ratio is used to achieve multi-color anti-counterfeiting under the single wavelength excitation.Thirdly,the multi-wavelength excitations were used to achieve multi-color luminescence in the same material;Through the above three technologies,the application of phosphors in anti-counterfeiting has been realized,and the application scope has been effectively expanded.