Ultrasound-assisted Coprecipitation YAG: Ce Phosphor Research And Luminescent Properties

Energy saving and environmental protection caused more and more attention of the governments. The LED has many advantages, such as no pollution, long life, energy conservation, and so on. Recent years, the industry of the LED has been regarded as an important part of the National strategic planning by many Countries.At present the majority method of manufacturing the commercial white LED is light conversion. Usually using the YAG phosphor coating on the surface of the blue LED chips, blue light excites the phosphor, and then the phosphor will emit yellow light. The two light mixed into white light. Compared with solid phase reaction method which is the majority preparation of the YAG:Ce phosphor now, co-precipitation method has the advantage of lower synthesis temperature, lower cost, uniform particle size, better light-emitting properties and so on. In this paper, the ultrasound-assisted co-precipitation method based on the co-precipitation was proposed. And do the research about the optimization of the ultrasound-assisted co-precipitation process. The physical and chemical properties are instability of the phosphor surface and its intensity easily degradation at high temperature working environment. To solve these problems, the phosphor has been coated by zinc oxide. The samples were characterized and analyzed by SEM, XRD, TG, PL, PSD et al.The main research content as follows:(1) Prepared the YAG:Ce phosphor by co-precipitation and ultrasound-assisted co-precipitation method. The phosphor prepared by reverse titration technique had higher luminous intensity than forward titration technique. The phosphor which prepared by ultrasound-assisted co-precipitation has better luminescence properties, and had a more uniform grain size and a narrower particle size distribution.(2) Synthesized YAG:Ce phosphor through ultrasound-assisted co-precipitation. Discussed the effects of the pre-burn-time, ultrasonic frequency, the sintering temperature and time on the YAG:Ce phosphor, pre-burn for Two hours, at the Frequence of80KHZ, sintering at1000℃and sintering for two hours are the best process conditions.(3) The phosphor was coated by zinc oxide. Discussed the amount of the Zinc oxide and the heat treatment time. When the zinc oxide coating amount is4%by weight and heated for60min is the best process conditions.