The Preparation, Structure And Fluorescence Properties Of Tricolor Phosphors For Near Ultraviolet W-LED

White LED is considered as the fourth generation of green lighting source.However, the luminous efficiency is still a crucial problem before white LED reallyenter into the lighting field and replace traditional lighting source. Presently, apromising method of combining blue, green and red-emitting phosphors withnear-ultraviolet (NUV) ranging from350to410nm chips has been proposed. Thisarticle selects the fluorine alumiiiate (Cai:Ali4032F2) and silicon phosphate(Ca5(P04):Si04) as a phosphor matrix by high temperature solid phase synthesis, andcommom rare earth ions (C3e‘ion’，丁b3ion, Fusion) are doped. Blue, green and redtliree kinds of light color phosphor are gained and their excitation spectra are nearultraviolet lfuorescence. In addition, the structures and optical properties ofas-prepared products are thoroughly characterized by using XRD, XRD-refmemcntand PL，respectively. The main results are summarized as follows:Cai2Al]40i.2F2(CAF)3: Cc+, Tb3" phosphor are synthesized by high temperaturesolid-state reaction. These oxyfluorides crystallize in cubic structure,/4yd spacegroup, crystal cell parameters a=b=c=l1.9687A, V=1714.5A’\Z=2’. The phosphorsexcitation spcctruin is broad band range of310-390nm, and by ch3anging the Ce ionand Tbvion doping amount can realize the change of color rfom blue to green light.Through the analysis of the crystal structure and the discussion of optica] properties,the ener^gy transfer mechanism rfom Ce ion to Tb” ion is investigated. Moreimportantly, when a certain amount of boric acid is added in the Cai2AI|4O^F2： Ce”’Tb1green phosphor, the lfuorescence intensity of the phosphors can be furtherincreased to about65%and research shows that the fiinction of H3BO3is double effect of cosolvent and dopant. What is more, by comparing Cai2Ali4032F2： C3e、Tb3十green phosphor and commercial green phosphor (Ce，Tb)MgAlnOi9and (La,Ce, Tb)PC>4，its color and color coordinates are very closed to the commercial greenpowder, the fluorescence intensity can be even more than commercial powder (La,Ce，Tb)PO‘Compared with commercial powder, the Cai2Ali4032p2material price islower, more stable physical and chemical properties, and can meet near ultravioletexcitation of white LED lighting needs.A kind of cheap and stable silicon phosphate Ca5(P04)2SiC>4: E3u+red phosphoris also synthesized by high temperature solid-state reaction. The as-preparedproducts are thoroughly characterized by using XRD, XRD-refinement, PL and color3coordinates, respectively，and further discusses the issues of the placeholder of Eu+ion and the affect of performance lfuorescence with alkali metal halide. Crystal cellparameters are obtained by means of XRD structure refinement with a=6.728人，b=15.4637A，c=10.0996A, a=p=y=90°, V=1049.79A3, Z=4. On the basis of the redphosphor, the lfuorescence intensity can be signiifcantly improved by adding alkali(LiCl, NaCl，KC1，LiF, LiBr) halide and U2CO3，especially for LiCl，and we alsoexpatiate on the effect mechanism of alkali metal. The excitation spectrum of bothred phosphor Ca5(PC>4)2Si04: E3u+and Ca5(PC>4)2Si04: E3u+，LiCl are nearultraviolet area and the main peak is395nm, emission spectrum of the main peak at615nm, the lfuorescence intensity of Ca5(P04)2Si043;Eu+，LiCl is closed tocommercial red phosphors Y2O2S: E3u+, and their color coordinates are similar withthe standard red phosphor.In the paper, the two kinds of phosphor matrix have the advantages of lowsynthesis temperature for rare earth ions doped, low cost, stable property andenvironment rfiendly. Their excitation spectrum fall in the region of310?390nmrnatcheable with the emisison of the white LED chips on the market. Therefore, thephosphors may find their promising application as phosphors of LED device. It isfundamental significance for design and development of novel phosphors toinvestigate the mechanism of energy transfer between rare earth ions andconcentration quenching of the luminescence center based on the crystal structure of the host and the site occupation of the rare earth ions.