Preparation And Characterization Of Cerium-doped Yttrium Aluminum Garnet Phosphor By Wet Chemical Method

White light-emitting diode (WLED) with lots of excellent properties, such as energy saving,long lasting life, small size, non-pollution, is to be considered as the most valuable lighting source and would become the fourth-generation lighting source. The current mainstream of the fabrication for WLED is combination of a blue LED and yellow emitting Y₃Al₅O₁₂:Ce (YAG: Ce³⁺).Phosphors with excellent performance can improve the luminescent efficiency of WLED effectively. YAG: Ce³⁺ phosphor can be prepared by solid reaction, wet chemical and combustion synthesis methods. Currently, the most of the commercial phosphors are prepared by solid reaction method, which need higher reaction temperature, time-consuming, equipment wired severely, and powders agglomerated so severely that could be used only after been ball milled. Lots of the scientific workers are devoted to improve the technology of solid reaction method or develop new fabrication process at home and abroad. After comparing and analyzing the existing synthesis methods, it's considered that co-precipitation method is most possible to be used in industry to replace the solid reaction method. In this paper, this method has been thoroughly studied and a new preparation method-microemulsion method has been invented.It has been intensivily studied about precipitation method that the influences on the processing and photoluminescence properties that exerted by different precipitant agents or different process parameters. It's been confirmed through experiments that the mixed precipitation agent (ammonia+ammonium bicarbonate) are the best precipitation agents, and the (H₂+N₂) mixed gas are the best choice of reduce atmosphere. The precursor powders evolved to YAG phase from amorphous at 900℃directly.In this paper, this method has been thoroughly studied, and the relative brightness of the phosphors which have been fabricated by this method has great luminescent property. The self-made phosphors are well matched to the blue LED and could be used to generate WLED. If the other properties such as color rendering index, color temperature, luminous decay of the packaged WLED have been studied, the two methods could be used in industry to replace the solid reaction method.The ternary phase diagrams of Oil/Water/Surfactant are determined by titrating. The YAG:Ce³⁺nanopowder phosphor has been fabricated by microemulsion method at 900℃and the YAG:Ce³⁺ nanopowders consist of fairly uniform, spherical particles. The particle size is distributed uniformly at 50 run. The microemulsion method is a promising new method, and deserved to be further studied.