Preparation Of YAG: Ce Phosphors By Coprecipitation Method

As white LED is a new kind of solid-state lighting that is energy saving and environmental friendly, possess a broad prospect in market. Blue LED and yellow fluorescence material are an admired combination at present which is also the mainstream of commercialized white LED. Yttrium aluminum garnet Y3Al5O12(YAG for short) is widely used as matrix material for the advantages of irradiation and electron impact persistence. Therefore Yttrium aluminum garnet mixed with Cerium (YAG.Ce) is the first choice of preparing yellow fluorescence.Currently, most of the on sale yellow fluorescence is adopted high temperature solid-s tate method which exist lots of disadvantages, such as high calcinations temperature and1ong insulation. Thus in order to reduce cost, co-precipitation method is the most appropri ate way with the comparison of other methods. By now there have been many researches about co-precipitation method, especially for YAG synthesis temperature which is about1000℃.Nevert the less, the research of precursor preparation has rarely been systematically studied.This paper aims at applying co-precipitation method to make YAG:Ce3+and trying to find the best parameters. It also studied the impact of process conditions for YAG:Ce3+, and discussed the influence of Cerium for phosphor structure and rotation property. The main contents and results are as follows.(1) It studied the precipitation influence for precursor preparation, and the univariate research shows that the best parameters are at room temperature,0.3mol/L mixture should be mix round intensely dripped to1.6mol/L NH4HCO3solution. pH should be adjust to about7.5after sedimentation, then aging about12hours.(2) It discussed the impact of the amount of Cerium to phosphor structure and rotation property,and the best Cerium amount is6%. It analyzed the reason for agglomeration and the measures of controlling agglomeration. With the solvent proportion of1:4by ethanol and water, using suitable amount of dispersant (polyethylene glycol) with ultrasonic wave concussion during the sedimentation process can improve dispersion and particle size.(3) A synthetic experiment has been made with all optimum technologies and parameters.the luminescence property and appearances were compared with commodity powder.The grain size of the powder of samples is smaller and has a tendency of uniting,but the grain size of commodity powder is a little bigger and heterogeneous.As for the luminescence property,the The luminous intensity of powder of samples is higher than commodity powder.