Synthesis And Fine Controllable The Spectrale Properties Of Orthosilicate Solid Solution Phosphors

Due to the low manufacturing cost,good chemical and thermal stability and many kinds of crystal structures,silicate phosphors have attracted considerable attention in recent years.In this paper,a series of Ce3+,Eu2+-doped alkaline earth silicate phosphor were prepared by the high temperature solid state reaction.(1)Ce3+-doped alkaline-earth silicate phosphors CamSr2-m-nBanSiO4:Ce3+,Li+(CSBS:Ce3+)were synthesized by a high temperature solid-state reaction.The crystal field splitting and the centroid shift from the free ion energy of 5d configuration were approximated from the spectrum for Ca2SiO4,Sr2SiO4 and Ba2SiO4 phosphors.According to XRD and literature reported,the phase transformation is inborn in Sr2-mCamSiO4:Ce3+ phosphors.Here,when the doped concentration of Ca2+ less than 80%(m ? 1.6),we report the structural phase transformation from monoclinic system ?-Ca2SiO4 to orthorhombic system ?'-Ca2SiO4.The phosphors excited by near-ultraviolet(nUV)light at wavelengths ranging from 200 nm to 400 nm demonstrate a broad asymmetric blue emission band.With the increase of the doped ion radius,the emission peak wavelength red shift firstly from 417 nm of Ca2SiO4 to 438 nm of Sr0.3Ca1.6SiO4,and then blue shift to 401 nm of Ba2SiO4.Since different plants have a slightly different adsorption spectrum,therefore,it is very important for fabricate precision light sources or solar spectral conversion(SSC)plastics films to synthesis controllable blue light emission of the phosphor that based on the UV-chips.(2)The designed BaCaSiO4:Ce3+,Li+ and Mg(Ca/Sr/Ba)SiO4:Ce3+,Li+phosphors were synthesized by a high temperature solid-state reaction.The samples were characterized by X-ray diffractometer,and the results showed that there were impurities in the samples,which did not form a pure phase.According to the emission spectrum,it can be seen that the emission peak of phosphor can be shifted within the wavelength range of 380 nm to 450 nm.Since different plants have a slightly different adsorption spectrum,the composition of phosphor can be changed to meet the growth needs of different plants.(3)Ca2SiO4:Eu2+ has been reported as a green phosphors with a broad emission band peaking at 500 nm under UV excitation.In this paper,Ca1.2Eu0.8SiO4 phosphors were synthesized by a high temperature solid-state reaction,sol-gel method,the one step response method and two step reaction method,finally found that the high temperature solid-state reaction is simple and high luminous efficiency.The original emission efficiency of Ca1.2Eu0.8SiO4 phosphors were significantly reduced by doping different halogen ions,and new emission peak appeared at 423 nm only when doped with fluoride.Subsequently,the luminescence properties of different CaF2 content were explored.As a result,with increasing CaF2 content,the color of phosphor changes from green to blue.After optimization,a new type of ultraviolet excitation Ca1.2Eu0.8SiO4 phosphor can be used for white light emitting diodes.