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 1-3μm.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.