Synthesis And Properties Of SrSi₂(B_x/Al_1-x)₂O₈ Trichromatic Phosphors

The development of white light emitting diodes（W-LEDs）have continuously been payed attention following the advancement of science and technology.High-quality trichromatic phosphors have become a hot topic of the research on the phosphor convered W-LEDs.Aluminum borosilicate trichromatic phosphors have the advantages of high-quality chromaticity,high color rendering index,high luminescence efficiency,low cost,good chemical stability,and easy spectrum control.It is expected to be the research direction of the new generation lighting field.Therefore,a serious of aluminum borosilicate trichromatic phosphors were synthesized by high temperature solid phase method.SrB₂Si₂O₈,SrAl₂Si₂O₈ and Sr(B_0.3/Al_0.7)₂Si₂O₈ were designed by adjusting the B/Al ratio,and the influence of the composition on the phase structure,unit cell parameters and structural integrity were studied.Single and double doped Eu³⁺/²⁺,Ce³⁺,Tb³⁺,Sm³⁺and other rare earth ions were used to generate red,green and blue trichromatic light and broad and narrow band spectral characteristics,to achieve efficient white light emission of a single matrix.The main research is as follows:1.The best synthesis process of SrB₂Si₂O₈ phosphor is 950°C for 6 h,the structure is orthorhombic,and it has Pnma（62）space group.By synthesizing SrB₂Si₂O₈:Ce³⁺/Eu²⁺and SrB₂Si₂O₈:Ce³⁺/Tb³⁺phosphors,high-efficiency blue and green emission is achieved,and there was energy transfer between Ce³⁺-Eu²⁺and Ce³⁺-Tb³⁺,and the transfer efficiency is as high as 93.4%and 79.7%,respectively.The transfer mechanism is dipole and dipole interaction.The results show that SrB₂Si₂O₈ phosphor may be used as candidate materials for blue and green emission in UV-excited W-LEDs.2.The best synthesis process of SrAl₂Si₂O₈ phosphor is 1350°C for 6 h,and the structure is monoclinic.By synthesizing SrAl₂Si₂O₈:Tb³⁺/Sm³⁺phosphor,when the concentration of Tb3+is 9 at.%,and Sm3+is 5 at.%.the luminescence intensity of the system is the maximum.The energy transfer efficiency between Tb³⁺-Sm³⁺is as high as85.4%,the transfer mechanism is the interaction of dipole and quadrupole.For SrAl₂Si₂O₈:Dy³⁺and SrAl₂Si₂O₈:Tb³⁺,Sm³⁺phosphors,the optimal CIE coordinates are（0.275,0.308）,（0.316,0.386）,respectively,which are very close to standard white light（0.330,0.330）.This indicates that Dy³⁺and Tb³⁺,Sm³⁺can achieve white light emission in a single matrix SrAl₂Si₂O₈ phosphor,respectively.For the SrAl₂Si₂O₈:Eu³⁺red phosphor,614 nm red light can be emitted under the excitation of 393 nm.The introduction of a charge compensator and a flux can significantly improve the luminescence intensity of the red phosphor.The best charge compensator is Li⁺,the best flux is H₃BO₃,and the optimum doping concentration of H₃BO₃ is 3 wt%.3.By adjusting the B/Al ratio,the optimal aluminum borosilicate matrix was determined to be Sr(B_0.3/Al_0.7)₂Si₂O₈,and the best synthesis process is 1250°C for 6 h.The optimal single-doping concentrations of Tm³⁺,Tb³⁺,and Sm³⁺are 1 at.%,17 at.%,and 3at.%,which can realize blue,green,and red light emission,respectively.For Sr(B_0.3/Al_0.7)₂Si₂O₈ phosphor,three doped Sr(B_0.3/Al_0.7)₂Si₂O₈:Tm³⁺,Tb³⁺,Sm³⁺/Eu³⁺,Sr(B_0.3/Al_0.7)₂Si₂O₈:Tm³⁺,Mn⁴⁺,Sm³⁺/Eu³⁺,Sr(B_0.3/Al_0.7)₂Si₂O₈:Tm³⁺,Pr³⁺,Sm³⁺/Eu³⁺phosphors were synthesized,finally,blue,green,and red light were emitted in a single matrix,and achieve white light emission in a single matrix.