Study On Preparation And Fluorescence Of Single-Phase White-Emitting Luminescent Materials For WLED

White LED is considered to be the fourth-generation solid-state lightingsource because of advantages such as low power consumption, high efficiency,long lifetime, and lack of toxic mercury, especially white LED using fluorescentconversion technology is becoming the focus of the luminescent materials.Furthermore, the preparation and research of luminescent materials for WLEDplays an important role on the development of WLED.This thesis focuses on developing near-UV pumped single-phased white-emitting phosphors, the preparation of monochromatic phosphor and theirluminescence properties investigation. The crystal structure of the experimentalsamples, the extent of reaction, surface morphology and fluorescence propertieswere characterized by X-ray diffraction, TG/DTA, scanning electron microscopy,infrared spectroscopy and fluorescence spectrum.Sr_3-x-yB₂O₆: xEu³⁺, yDy³⁺near-UV pumped single-phased white-emittingphosphors were synthesized by high temperature solid state reaction. And thesintering temperature, holding time, the doping content of rare earth ions, chargecompensation agent were studied. The result shows these factors have grateimpact on the formation of particles, grain size, and surface morphology of theluminescent materials. In addition, the luminescence mechanism of Sr_3-x-yB₂O₆:xEu³⁺, yDy³⁺were studied. The emitting colour of preparation was controlled byratio of Eu³⁺: Dy³⁺, the white light with CIE coordinates of （x=0.30, y=0.25） wasobtained by the ratio of Eu³⁺: Dy³⁺=1:1.The Ba_3-x-yBP₃O₁₂: xEu³⁺, yDy³⁺as near-UV pumped single-phased whitelight-emitting material were synthesized by high temperature solid state reactionmethod. The sintering temperature, holding time, the doping content of rare earth ions and charge compensation were studied. And the result shows that thesefactors have great affect on particle formation, grain size and surface morphology.The optimum sintering temperature and holding time is800℃,4h. Thefluorescence intensity of the white light emitting material is stronger when thedoping amount of Dy³⁺is3%and molar ratio of Eu³⁺: Dy³⁺is1:1. Chargecompensation has a great influence on the fluorescence properties. When addingNa⁺as charge compensation the fluorescence intensity of white light-emittingmaterial is highest in this work. It can be calculated by CIE coordinate （x=0.35,y=0.28） that the as-prepared white light emitting material can be used preferablyfor the WLED.