Preparation And Characterization Of YAG:Ce³⁺（Ga,La,Pr） Phosphor

In the liquid crystal display （LCD） and large screen display, White LED has beenwidely used as the backlight. The performance requirements of LED become stringent.Especially, the color rendering index and luminous efficiency of LED have higherrequirements. In the backlight application, most of ordinary white LED is generatedby the blue light and yellow light. The disadvantage is a high color temperature, thelack of a red component in spectrum. This white LED has small color gamut, lowcolor rendering index. To solve the problem，based on the YAG yellow phosphor,doping Ga, La, Pr made new kinds of phosphor. Study on four kinds of phosphorpreparation of （Al1-x，Gax）5Y3O₁₂:Ce³⁺、Al5（Y1-x, Gax）3O₁₂:Ce³⁺、Al5（Y1-x，Lax）3O₁₂:Ce³⁺、（Al1-x，Gax）5（Y1-y，Pry）3O₁₂: Ce³⁺,and its application in white light LED. Inorder to improve the luminescent properties of white LED，expanding the applicationarea. The main results are as follows:The new four phosphors are prepared using high temperature solid-state method，and test the emission spectra of the new phosphors：（1）（Al1-x，Gax）5Y3O₁₂:Ce³⁺andAl5（Y1-x, Gax）3O₁₂:Ce³⁺phosphor, when element Al is replaced by element Ga willcause blue shift of the emission peak, and the blue shift is about8nm. Red shift ofemission peak can be observed when Y element is replaced by Ga element, and thered shift is about11nm.（2）（Al1-x，Gax）5（Y1-y，Pry）3O₁₂: Ce³⁺phosphor, Twoemission peaks of532nm and610nm are detected when Ga and Pr are doped.（3）Al5（Y1-x，Lax）3O₁₂: Ce³⁺phosphor, when element Y is replaced by element La willcause red shift of the emission peak, the emission peak at549m.Four kinds of phosphor were LED package aging test. The earlier stage,attenuation is more serious. In later stage of aging, the luminous intensity remainedabout the same. The color difference is in the allowed range. The phosphors canimprove the color gamut of the backlight, the optical performance of TV backlightcan be improved. Study on the preparation technology of the high temperature solid-state method.The results show that: high temperature and constant temperature time is suitable，thegrinding force is appropriate, wet-processing, both of them can improve theluminescent properties of phosphor.