Research On Growth And Properties Of Phosphor By The Optical Floating Zone Technique

In recent years, the white-light-emitting diodes(LEDs) source has been developed rapidly. It has high efficiency, energy saving, long life, environmental friendliness and other characteristics. However, the traditional white LED devices have many shortages, such as complex encapsulate,low efficiency and poor physical and chemical characteristics. New type of phosphor and packaging technology are in urgent need of development research. At present, new kinds of phosphor mainly include: glass, ceramics, Y3Al5O12 single crystal and their complexes. But compared with Y3Al5O12 single crystals and ceramics, eutectic has more excellent luminescence efficiency.Considering the development of LED lighting, the growth mechanism and performance of two kinds of new type of eutectic fluorescent materials were studied. They are Ce,Si:Y3Al5O12-Al2O3 eutectic and Ce,Gd: Tb3Al5O12-Al2O3 eutectic. The SEM and XRD were tested for Ce,Si: Y3Al5O12-Al2O3 eutectic and the properties of white LED were also analyzed. The Ce: Tb3Al5O12-Al2O3 eutectic and Ce:Al2O3-Tb1.5Gd1.5Al5O12 eutectic with different Ce concentrations were also grown. Their fluorescence properties and the performance of white LED package were analyzed. It is learned that eutectic is three-dimensional network structure, composed of two kinds of crystal phases. The optimal doping concentration of Ce ions in Y3Al5O12- Al2O3 eutectic is 1.6% and the luminous efficiency is as high as 82.03lm/W. The density of Ce:Y3Al5O12- Al2O3 is about 4.3 g/cm3. The luminous intensity of Ce:Y3Al5O12-Al2O3 is better than Ce, Si:Y3Al5O12-Al2O3. The luminous efficiency is as high as 41.06lm/W, when the doping concentration of Ce in Tb3Al5O12-Al2O3 eutectic is 2.0%. The quenching concentration of Ce is higher than 2.0%. The luminous intensity of Ce:Al2O3- Tb1.5Gd1.5Al5O12 eutectic, reached up to 48.78lm/W, which is better than that of Ce: Tb3Al5O12-Al2O3 eutectic.