Synthesis And Characterization For The Series Of (Y_2.95-xGd_xCe_0.05)Al₅O₁₂ Warm White LED Phosphor

Because of petrifaction resources’ lack, many countries have attached importancetoworldwide energy sources crisis and bring lighting thrift techniques, especially white LEDinto national development stratagem. Compared with conventional lighting sources,whiteLED has many merits in energy saving, compact optics designs, cold source,startup at lowvolt or electrical current, long life-span, rapid brightness and color changes, aseismatic,recyclable, unpolluted and so on, there’s obvious benefits to economic and environment.Whereas, if white LED illuminance would realize finally, there will be much works in playingdown cost and increasing LED’ color reveal index, luminescence efficiency, luminous fluxand life-span. This paper intends to prepare YAG:Ce yellow phosphor by high-temperaturesolid state reaction, investigate several technique parameters which affect phosphor’s physicaland chemical properties, and study the effects of different ions doping on fluorescenceemitting spectrum, further more, gained luminescence phosphor with good color revealpropertiy, lighting extraction, luminescence efficiency.The following is included:1) The present status and prospect of white LED illumination industry is reviewed firstly.Then it analysises the light emitting principle, realization methods, and puts the emphasis onthe preparation techniques of the phosphors for white LED.2) The YAG yellow phosphor is synthesized by high-temperature solid state reactionunder reducing atmosphere, and the chemical and physical properties are characterized withmolecule fluorometry.3) A series of rare earth complex oxides, i.e.(Y_2.95-xGd_xCe_0.05)Al₅O₁₂were synthesizedby a high temperature solid-state reaction method and their crystal structure and luminescentproperties were investigated. When Gd3+replaced Y3+partly, the lattice constant of the samplewas slightly increased. The emission spectra of Ce3+show a tendency of red-shift with theincrease of Gd3+content in (Y_2.95-xGd_xCe_0.05)Al₅O₁₂system, and it is beneficial to reducing thecorrelated color temperature of white LED devices and raising the color rendering index. 4) The formation of YAG crystal style and doping mechanism are also discussed simply.YAG belongs to cubic crystal system, and the ion doping of YAG is based on the crystal fieldeffect.