Effect Of Boron Or Boron/Na Co-doping OnLuminescence Properties Of The Ca₂Si₅N₈:Eu²⁺ Phosphor

White LED has a huge application prospect for the advantages of small size,high luminous efficiency,energy saving and environmental protection in the field of lighting since the 21st century.At present,the combination of a blue LED chip and a yellow phosphor has the disadvantages of high color temperature and poor color rendering.The main reason for its color distortion is a serious lack of red light.Therefore,the development of high-performance red phosphor Imminent.Due to its high chemical stability,high luminous efficiency and warm color temperature,Ca₂Si₅N₈:Eu²⁺nitride phosphors have become the research hot spot in the field of lighting.However,Ca₂Si₅N₈:Eu²⁺phosphor preparing process and post-storage conditions are greatly constrained.Therefore,in view of the above problems,this thesis focuses on exploring the role of doped boron or boron-doped sodium in the synthesis process and the influence on the luminescent properties of Ca₂Si₅N₈:Eu²⁺phosphor.In this paper,two kinds of boron sources such as borane ammonia and sodium borohydride were used as doping raw materials.BN-coated Ca₂Si₅N₈:Eu²⁺phosphors were synthesized by ammonothermal method.The effects of doping content of two boron sources on the luminescence properties of Ca₂Si₅N₈:Eu²⁺are disscussed.The feasibility of improving the luminescent properties of Ca₂Si₅N₈:Eu²⁺phosphors by using two kinds of boron source dopants is probed.When the luminescent property of phosphor is better,the doping amount of boron source is obtained.The main conclusions are as follows:1.Study on the influence of boron doped on synthesis and structure of the Ca₂Si₅N₈:Eu²⁺phosphor.Borane ammonia is doped as a boron source,metal Ca,Eu and amorphous Si are used as raw materials,liquid ammonia is used as a solvent,the raw materials were mixed by liquid,then synthesize Ca₂Si₅N₈:Eu²⁺phosphor on the condition of nitrogen atmosphere 1230℃,4h.The XRD spectrum analysis shows that boron doping does not change the crystal structure of the phosphor,and is still monoclinic with a cell volume of 0.697 nm³,and the product contains the BN（JCPDS:74-1978）phase except the main phase Ca₂Si₅N₈（JCPDS:82-2489）.The micromorphology analysis of FE-SEM and TEM shows that a small portion of the boron enter the lattice of the phosphor,most coat on the outer surface of the phosphor in the form of BN,and the thickness of the surface of the bread is 139.50 nm.2.Study on the influence of boron doped with different concentrations on luminescence properties of the Ca₂Si₅N₈:Eu²⁺phosphor.With the increase of boron doping（0.02 g⁰.06 g）,the band width of the product decreased from 2.16 eV to 2.10eV and then increased to 2.11 eV,When the doping concentration is 0.05 g,the band gap is 2.10 eV,with the increase of boron doping in the later period,the band gap is2.11 eV.The PL study shows that when boron doping concentration is 0.05g,the emission peak is at 590 nm,which is red shift 20 nm compared to the product without boron doped,and the luminescence intensity is also increased by about 1.7 times.Then the boron doping amount increased to 0.06g,the emission spectrum of the product was blue shifted and the intensity of luminescence was no longer increased.It is determined that when the boron doping amount is 0.05g,the luminescent properties of the phosphor are better.3.Study on the effect of boron and Na⁺co-doping on synthesis and structure of the Ca₂Si₅N₈:Eu²⁺phosphor.XRD studies that when the amount of boron and Na⁺increased from 0.03g to 0.07g,the product phase did not change significantly.Besides the main phase Ca₂Si₅N₈,the BN phase also existed,while the volume of the product cell decreased（0.7135 nm³）and then increased（0.7297 nm³）.TEM studies show that the thickness of Ca₂Si₅N₈:Eu²⁺phosphor bread is 368.78 nm.4.Study on the effect of boron and Na⁺co-doping on luminescence properties of the Ca₂Si₅N₈:Eu²⁺phosphor.The PL test shows that the highest emission peak of the product is shifted from 570 nm to 604 nm with the change of doping concentration.When the doping concentration of B and Na⁺increases to 0.06g,compared with only boron,the luminescence strength of the product is increased by about 5.8 times,and its emission spectrum is located at 604 nm,which continues to increase in a steady trend.Product emission peak positions of red shift compared with the boron doping.The luminescent properties of phosphor are better when the concentration of boron and Na⁺is 0.06g.5.The difference of luminescent properties of phosphor by B and Na⁺doped with single B was studied.Compared with the single B（590 nm）doping,the highest emission peak of the co-doped（605 nm）shifted about 15 nm,and the luminescence intensity increased by about 5.8 times.