Preparation And Properties Of Eu Doped CaAlSiN₃ And YAG Red Phosphor

WLED was called the fourth-generation light for their advantages of long life 、energy saving and environmental protection. WLED with blue ship match YAG yellow phosphor has a low color rendering index, so it need to use red phosphor which has a high price to improve the CRI. In this study we choose two types of Eu doped red phosphor research affect of synthesis method and conditions on the fluorescence properties and micro structure and explore a low cost ways to synthesis the red phosphor.CaAlSiN3:Eu2+has a stable property and can be motivated by near ultraviolet chip and blue chip while the current synthesis method use inert nitrides as raw materials, this need harsh synthetic conditions and the phosphor is expensive; our research use high activity Al、Si、CaH2 as raw materials and successfully obtained CaAlSiN3:Eu2+at 1450℃ atmospheric pressure, reducing the synthesis temperature greatly. We analyze the reaction process through phase of each temperature, and reducing impurities in phosphor by changing the ratio of raw material, we also studied the impact of calcinature temperature、holding time、Eu2+concentration on luminescent properties of the phosphor. The optimal conditions is Si:Al:CaH2=0.95:0.90:2, calcinated at 1450℃ for 6h, doping concentration of Eu is5%.YAG:Eu3+ red phosphor and YAG:Ce phosphor belong to the same style, it can be motivated by both the near ultraviolet chip and blue chip, can be used as red phosphor for LED and other optoelectronic devices. The high temperature solid state reaction needs a high temperature which lead to serious aggregation and difficult to control the morphology. Yttrium aluminum carbonate precursors which can be transferred to pure YAG nano powders at low calcining temperature were prepared by co-precipitation method. The composition and filtration performance of precipitation and the phase purity and particle size of YAG power were characterized by IR、XRD and SEM. The results show that amorphous precipitation that easy to filter can beeasily prepared using metal nitrates as raw materials and ammonium bicarbonate as precipitant by reverse precipitation method and control the final pH of about 7.5 at the same time. The temperature to obtain pure YAG phase material by calcining this amorphous precipitation is 200 ℃ lower than that by calcining crystalline yttrium aluminum carbonate precursor. YAG:Eu3+red phosphor which is well dispersed and uniformly distributed spherical particles with size around at 60 nm in diameter was obtained when calcinated at 1100℃. We observed unusual emission peak located at709 nm, the phosphor has a maximum luminous intensity when the doping concentration of Eu3+ is 10% and 4wt% flux BaF2 is added.