Preparation And Luminescence Properties Of Eu,Ce Ion Doped M₅(BO₃)₃F(M=Ca,Sr)

In solid-state lighting systems,phosphors are a key material for adjusting the luminous efficiency and color rendering index of white light emitting diodes(LEDS).Phosphor-converted white light-emitting diodes(pc-WLEDs)are based on the integration of blue LED chips and yellow phosphors Y3Al5O12:Ce³⁺(YAG:Ce).Due to its green environmental protection,long life,energy saving and other advantages,it has caused more and more research interest.Therefore,the development of new phosphors will have great practical significance and theoretical value.M5(BO₃)₃F(M=Ca,Sr),as a luminescent material matrix,has the characteristics of stable chemical properties,simple synthesis process,and abundant M ion lattices.Rare earth ion-doped phosphors often use Eu and Ce ions as activators.In this paper,we synthesized Eu and Ce ion-doped M5(BO₃)₃F(M=Ca,Sr)luminescent materials.Characterize the structure,test the luminescent properties,calculate the rare earth ion preferentially occupy the lattice,and study the relationship between the luminescent properties and the crystal structure.The main tasks as follows:1.Study on the preparation of Ca5(BO₃)₃F:Eu³⁺ red phosphor,the relationship between the luminescence properties and the crystal structure.The Ca5(BO₃)₃F:Eu³⁺ powder material was prepared by high temperature solid phase method,and the XRD diffraction pattern analysis results showed that the pure material was prepared without other impurities.The photoluminescence spectrum was used to study the excitation and emission properties of Eu³⁺in Ca5(BO₃)₃F.Under the excitation of ultraviolet light,the substance emits red light.The excitation spectrum has two different O2-?Eu³⁺ charge transfer broadband peaks at 266 and 283 nm,respectively.The calculation of the environmental factor he,the standard deviation of the environmental factor(EFSD),and the bond energy can be inferred that Eu³⁺preferentially occupies the Cal and Ca2 lattices,which is consistent with the experimental test results.2.A new light-emitting material Sr_F:Eu³⁺ was synthesized through high-temperature solid-phase reaction in an air atmosphere.The luminescent properties and crystal lattice occupation of Sr5(BO₃)₃F:Eu³⁺phosphors were studied.After repeated experiments,Eu randomly presented two unique luminescence phenomena in the same matrix Sr5(BO₃)₃F:one showed an unusually strong 5D0?7F0 emission of Eu³⁺ at 572nm,and the other showed a strong 5D0?7F2 emission of Eu³⁺at 619nm.According to the calculation results of bond energy theory,the values of ?EEu³⁺-O2-Sr1,?EEu³⁺-O2-Sr2 and ?EEr³⁺-O2-Sr3 are very close,which shows that the abilities of Eu³⁺ ions to occupy the Sr1,Sr2 and Sr3 sites in Sr5(BO₃)₃F are similar.3.Eu²⁺/Eu³⁺ or Ce³⁺/Eu³⁺ co-doped Sr5(BO₃)₃F luminescent materials were prepared in a N2-H2 reducing atmosphere using a high-temperature solid phase method.These compounds show good photoluminescence properties.Under the excitation at 376nm of Eu²⁺/Eu³⁺ doped Sr5(BO₃)₃F,Eu³⁺ and Eu²⁺ ions can produce red-orange dual-center emission.The emission peak of Eu²⁺is located at about 600nm,and the characteristic emission of Eu³⁺ in the red region can effectively improve and regulate the luminescence of Eu²⁺.At the same time,we obtained Ce and Eu ion co-doped Sr5(BO₃)₃F,this kind of adjustable luminescence material.its spectrum shows the adjustable luminescence characteristics from blue to white.The energy transfer behavior from Ce to Eu was confirmed.The results show that Sr5(BO₃)₃F:Eu³⁺/Eu²⁺ and Sr5(BO₃)₃F:Ce³⁺/Eu³⁺ phosphors have good application prospects for LED plant growth and white LED,respectively.