Synthesis And Photoluminescence Properties Of Rare Earth Doped(Halogen)Borates

White light-emitting Diodes have been favored by people due to their high efficiency,energy saving,long lifetime and other advantages,and are called the fourth generation of green lighting sources.At present,the realization method of white LED is mainly phosphor conversion,and the luminous performance of phosphor is determined by its main performance indexes,such as color rendering,color temperature,luminous efficiency and so on.However,the phosphor that can be used for white LEDs have the disadvantages of high temperature,low color rendering index,and unstable luminescence.Therefore,it is of great significance to develop a new type of phosphor for white LED.(Halogen)borate is one of the ideal host materials for rare earth-doped phosphors due to its many types,low calcination temperature,simple synthesis process,high luminous efficiency,and high thermal and chemical stability.In our study,we prepared three(halogen)borate systems Ba3Y2(B2O5)3,Ca2BO3Cl,Sr5B3O9F through the sol-gel method and the traditional high-temperature solid phase method,and their spectral properties were studied,and samples with better performance were encapsulated with white LED.The details are as follows:1、Ca2BO3Cl:Ce3+,Na+blue phosphor and Ca2BO3Cl:Eu2+ yellow phosphor were prepared by high temperature solid phase method,and discussed their photoluminescence properties in detail.At the same time,we explored the multi-site occupation phenomenon of Ce3+ions,and explained the red shift of the emission peak of Ca2BO3Cl:Ce3+,Na+ phosphors.We measured the thermal stability of Ca2BO3Cl:Ce3+,Na+ and Ca2BO3Cl:Eu2+samples,and finally encapsulated white LED devices.2、Ba3Y2(B2O5)3:4 mol%Ce3+and Ba3Y2(B2O5)3:4 mol%Ce3+,yTb3+phosphors were synthesized by the sol-gel method.We found that there are two kinds ofCe3+ion in Ba3Y2(B2O5)3:4 mol%Ce3+samples,which are further verified by the test of fluorescence lifetime.At the same time,We tested the fluorescence lifetime of Ba3Y2(B2O5)3:4 mol%Ce3+,yTb3+samples to prove the existence of energy transfer between Ce3+and Tb3+,and analyzed the energy transfer between Ce3+and Tb3+according to the Inokuti-Hirayama(I-H)model.The results show that the energy transfer mode of Ce3+→ Tb3+is electric dipole-electric dipole interaction.3、A series of Sr5B3O9F:Ce3+,Na+,Sr5B309F:Eu3+,Na+,Sr5B3O9F:Tb3+,Na+,Sr5B3O9F:Dy3+,Na+ and other(halogen)borate luminescent materials doped with different rare earth ions were prepared by high temperature solid phase method,and explored their luminescence properties.And found that there is energy transfer between Ce3+and Tb3+,and further synthesized Sr5B3O9F:Ce3+,Tb3+,Na+light color tunable phosphor.By changing the doping ratio between Ce3+and Tb3+,the emission can bechanged from blue to cyan and then to green.4、Sr5B3O9F:Sm3+,Eu3+,Na+double-doped phosphors were prepared by high temperature solid-phase method,and discussed the energy transfer process in this phosphor in detail.The energy transfer mechanism between Sm3+and Eu3+is analyzed by the Dexter multipolar interaction energy transfer formula.The results show that the energy transfer of Sm3+→ Eu3+is mainly based on the electric dipole-electric dipole interaction.