Study On Preparation,Properties And Application Of Rare Earth Doped Trichromatic Phosphors For White LED

The huge W-LEDs lighting market prospect has attracted worldwide attention.High electro-optical conversion efficiency and cost control are the goals of our research.The primary task at this stage is to optimize the use parameters and lifespan of commercial W-LEDs.The decisive role is determined by the luminescence characteristics and performance of the phosphor.The phosphor is mainly composed of a powder matrix and an activator,most of which use rare earth ions as the activator.In this thesis,phosphors that can be excited by near-ultraviolet light and blue light were synthesized using parallel experimental design methods,and the luminescence properties of these phosphors were studied to develop and screen high-performance phosphors that can be hopefully used in W-LEDs.The chloroapatite?Ca₅?PO₄?₃Cl,abbreviated as ClAP?phosphor activated by different rare earth ions was synthesized by molten salt method.The crystal structure of chloroapatite was studied for ClAP crystallites with well-developed and uniform size,Sintering temperature,molten salt ratio and calcination time affect the phase and morphology of ClAP.When the sintering temperature is 600?,the?ClAP/molten salt?ratio is 1:3,and the calcination time is 4 h,the ClAP matrix has the best morphology and uniform size.On this basis,the luminescence properties of Eu³⁺,Eu²⁺,Tb³⁺and Sb³⁺phosphors doped with ClAP as the matrix were studied,and ClAP:Eu³⁺excited by near ultraviolet?UV?chip was a bright red phosphor,and ClAP:Eu²⁺was a bright blue Color phosphor,ClAP:Tb³⁺is a bright green phosphor,ClAP:Sb³⁺is a blue-green phosphor.The matrix of calcium scandate?CaSc₂O₄?was synthesized by high-temperature solid-phase method,and the effect of calcination temperature on its phase and morphology was studied.When the calcination temperature is 1400?,the calcium scandate matrix is??a pure phase,and the microscopic morphology is elliptical particles with an average size of 1-3?m.We analyzed the crystal structure of calcium scandate,studied the effect of different Eu³⁺doping on the phase and luminescence properties of CaSc₂O₄,and optimized its doping concentration.Under the excitation of near ultraviolet?ultraviolet?and blue light chips,when the concentration coefficient x=0.1,CaSc₂O₄:Eu³⁺is the best doping red phosphor.Based on the synthesis of calcium scandate?CaSc₂O₄?matrix by high-temperature solid-phase method and its structural analysis,the effect of different Ce³⁺doping on the phase and luminescence properties of CaSc₂O₄ was studied,and its doping concentration was optimized.Under the excitation of the blue chip,when the concentration coefficient x=0.05,CaSc₂O₄:Ce³⁺is the green phosphor with the best doping concentration.