Study On Preparation And Fluorescence Properties Of Rare Earth Ion Doped Silicate Phosphors

White LED as a fourth-generation solid-state lighting source has a lot ofadvantages, especially as fluorescent conversion white LED is now the focus ofthe study. And the preparation and research of White LED luminescent materialsplays an important role and value for the development of white LED.Rare earth ion activated alkaline earth silicate luminescent phosphormaterials as a single matrix white LED matrix has been widely used in recentyears for its high chemical stability, resistance to oxidation, moisture resistance,and does not react with the package resin. Ce³⁺，Tb³⁺and Eu³⁺ions are threeimportant trivalent rare earth ions which have been used to produce blue, greenand red emission.The white emitting phosphor Ca₂MgSi₂O₇with rare earth ion doped wassynthesized by solution-combustion method and solid-state reaction technique.We had discussed the process parameters of solution-combustion method andsolid-state reaction technique. researching the influence of different calcinationtemperature on the phase composition, morphology and fluorescence propertiesof phosphors which synthesised via solution-combustion method and solid-statereaction technique; discussing the influence of secondary calcination temperatureand amount of urea on the morphology of phosphors and gained the optimalparameters. The experiment proved that when synthesized by solid-state reactiontechnique, the best luminescent materials were obtained under the calcinationtemperature at1150℃, and when synthesized by solution-combustionmethod,the best furnace temperature of is600℃, the best secondary calcinationtemperature is1000℃, the optimum molar ratio of urea and metal ions is3:1.The white emitting phosphor Ca₂MgSi₂O₇was synthesized by solution-combustion and solid-state method. Under the same concentration single dopedEu³⁺,double-doped Eu³⁺/Ce³⁺and Eu³⁺/Tb³⁺, three doped Eu³⁺/Ce³⁺/Tb³⁺. Analysis of the luminescence mechanism and contrast fluorescence propertiesunder the same kind of conditions. Ultimately concluded: When the single dopedEu³⁺ion concentration is1%, the luminous intensity of the luminescent materialsis strongest. Double-doped Eu³⁺and Ce³⁺molar ratio of1:1.5, the luminescenceintensity is strongest; optimal Eu³⁺and Tb³⁺molar ratio is1:1. When the threedoped Eu³⁺, Ce³⁺, Tb³⁺molar ratio is1:1.5:1, the fluorescence intensity isstrongest. Under the same conditions, the phosphors prepared by Solution-Combustion method is better than solid-state method. By comparison of thechromaticity diagram, the phosphors prepared by the two method emit white light.luminescent materials that prepared by solution-combustion method haveadvantages of warm white light emitting, excellent color Rendering and lowcolour temperatureand, making up the defects of the insufficient red light. Sooverall it seen the phosphors prepared by Solution-Combustion method is betterthan solid-state method.