Study On Structure Regulation And Photoluminescence Of M₁₀?TO₄?₆X₂ Typed Phosphors

As the 4th-generation lighting source,WLEDs have quickly become the mainstream in the lighting field due to their good thermal stability,luminous efficiency,and low power consumption.Phosphors are an important part of LEDs,so the development of phosphors with excellent luminous properties has become a research hotspot.By incorporating foreign ions,apatite structure compounds of M₁₀?TO₄?₆X₂type will have a flexible and variable crystal field and become an excellent matrix crystal for doping rare earth ions.Therefore,in this paper,several M₁₀?TO₄?₆X₂ type apatite phosphors were investigated by structure regulation,and their photoluminescence properties were studied.The details are as follows:?1?A series of Sr₆Ca₄?PO₄?₆F₂:Eu²⁺and Sr₆Ca₄?PO₄?₆F₂:Eu²⁺,Dy³⁺apatite phosphors were synthesized by high-temperature solid-phase method under H₂/N₂reducing atmosphere.The results of fluorescence spectrum and thermoluminescence spectrum indicated that Dy³⁺ions would generate trap centers,which could effectively increase the luminous intensity of Eu²⁺ions as a medium for transfering energy.After Si⁴⁺-P⁵⁺charge compensation,Sr₆Ca₄?PO₄?₆F₂:Eu²⁺,Dy³⁺,Si⁴⁺phosphors were synthesized as comparative samples.The results of XRD refinement,thermoluminescence analysis,thermal quenching analysis and fluorescence decay curve were proved that the existence of charge defects in Sr₆Ca₄?PO₄?₆F₂:Eu²⁺,Dy³⁺.?2?A series of Ca₄La₆?Al O₄?_x?Si O₄?_6-xO_1-x/2:y Eu²⁺green apatite phosphors were synthesized in the same preparation environment as above.The related tests on the samples indicated that adjusting the ratio of Al O₄^5-/Si O₄^4-could improve the luminous intensity of Eu²⁺and achieve the red shift of spectral.In addition,the effects of different doping concentrations of Eu²⁺ions on the emission spectrum intensity and emission peak were also analyzed,and the energy transfer between the two luminescent centers of Eu?I?and Eu?II?and the blue shift phenomenon of thermal quenching spectrum were mainly studied.?3?A series of Ca₄La₆(Al_1.5Si_4.5O_24-1.5xN_x)O_0.25:0.04Eu²⁺apatite structure phosphors were synthesized by doping N^3-ions based on the above experiment.XRD tests of the phosphor indicated that trivalent N^3-ions replaced divalent O^2-ions,and no hybrid phase was generated.According to the results of fluorescence spectrum and thermal quenching analysis,proper doping concentration of N^3-ions would improve the luminous intensity,adjust the luminescent color of Eu²⁺ions,and not affect the energy transfer between Eu?I?and Eu?II?.In addition,doping with N^3-ions would also effectively improve the thermal stability of the sample.