The Synthesis Of Cerium-doped Yttrium Aluminum Garnet Powders And Oxide By Microbial-copreciptation

Early in the 1970s, people have successfully developed the cerium-dopped yttrium aluminum garnet, which can be used as ultra-short rays flying-spot phosphor, this YAG:Ce phosphors produces green light under cathode rays's excitation. Because of its small volume , low calorific value ,less energy consumption, long lifetime, no pollution, plane encapsulation and be easy developed into frivolous artful small products. Semiconductor light emitting diode (LEDs) is regarded as the forth generation lamp after Incandescent lamp, fluorescent lamp and HID lamp, which with application prospect will replace traditional lighting in the future. It has reported that, so far, YAG:Ce phosphors is the most suitable phosphor used in the white LEDs commercial market. Therefore in order to improve different application of the luminous efficiency,it is value to improve YAG:Ce's Luminescent Properties.By designing orthogonal experiment and combining XRD analysis results, we have determined the optimum technological conditions of microbial–coprecipitation method. We used NH4HCO3 as precipitator,and synthetized YAG:Ce nanopoweders by coprecipitation and microbial–coprecipitation method. Although, we analyzed these two kinds of nanopoweders comparatively by XRD,FTIR,TEM,fluorescent property and so on. The experimental results demonstrate that microbial– coprecipitation method is better than coprecipitation showing on the dispersion of nanometer particles and fluorescent property.We synthetized Y2O3 nanopoweders by coprecipitation and microbial– coprecipitation method, and analyzed comparatively properties of poweders obtained under different conditions. We found and explained the advantages of microbial– coprecipitation method. Finally, we analyzed the bonding between ions and yeast cells through FTIR.We chose oxalic acid , ammonium bicarbonate and ammonia as different precipitators, and synthetized CeO2 nanopoweders by coprecipitation and microbial– coprecipitation method. And we put forward erery precipitator's merits and demerits. Through analytizing, we found that ammonium bicarbonate is better than the others.Finally, we analytized and proposed the synthesis mechanism of microbial– coprecipitation method briefly.