Study On The Preparation And Properties Of Ce³⁺ Doped Y_3-xM_xAl_5-xSi_xO₁₂?M=Ba,Sr,Ca,Mg? Fluorescent Materials

White light-emitting diodes?LEDs?have great market competitiveness in the solid-state lighting market due to their high efficiency,low cost,long life,and environmental protection.At present,the most common method for manufacturing white LEDs is to coat Y₃Al₅O₁₂:Ce³⁺(YAG:Ce³⁺)yellow phosphor on a blue LED chip.YAG:Ce³⁺yellow phosphor is one of the core materials of white LED,which plays a decisive role in the light color quality of white LED devices.The existing research shows that cationic substitution is an ideal method to improve or modify the luminescence properties of YAG:Ce³⁺.Therefore,we adopted a non-equivalent co-substitution method to design the structure based on YAG:Ce³⁺,then adjusted its optical performance,and studied the structural effect relationship between the optical performance modulation and the local crystal environment.The excellent optical performance indicates that the phosphor is used as a fluorescent material for high-quality white LED devices.The main work and conclusions are as follows:?1?New solid-solution phosphors Y_3-xM_xAl_5-xSixO₁₂:Ce³⁺?M=Ba,Sr,Ca,Mg,x=0.2,0.4,0.6,0.8,1.0?have been achieved via the non-equivalent co-substitution of Y³⁺-Al³⁺with M²⁺-Si⁴⁺in YAG:Ce³⁺.The XRD data and Rietveld refinement confirmed that M²⁺ions occupy the dodecahedral Y³⁺site,Si⁴⁺occupies the tetrahedral Al³⁺site of the garnet phosphor.The crystal structure is maintained.The evolution of the crystal structure with the M²⁺ion radius is analyzed.The cell volume and lattice constant increase as the ion radius increases.?2?The optical properties of some phosphors of Y_3-xM_xAl_5-xSixO₁₂:0.06Ce³⁺?M=Ba,Sr,Ca,Mg,x=0.2,0.4,0.6,0.8,1.0?are realized due to the regulation effect of M²⁺-Si⁴⁺ion on the local structure.In the Y_1.94MAl₄SiO₁₂:0.06Ce³⁺?M=Ba,Sr,Ca,Mg?phosphor,as the radius of the metal ion decreases,the emission spectrum under 460nm excitation shows a continuous red shift.?3?In this paper,the internal quantum efficiency?IQE?under the condition of 1mol of M²⁺-Si⁴⁺substitute is calculated.The IQE of Y_1.94MAl₄SiO₁₂:0.06Ce³⁺is calculated as 92.89%,89.54%,82.55%,81.43%for M=Ba,Sr,Ca,Mg,respectively.The IQE of YAG:Ce³⁺is 89.97%.The results show that Y_1.94MAl₄SiO₁₂:0.06Ce³⁺?M=Ba,Sr,Ca,Mg?has excellent light conversion ability and is suitable for white LEDs.?4?The thermal stability of Y_1.94MAl₄SiO₁₂:0.06Ce³⁺?M=Ba,Sr,Ca,Mg?increases with the increase of M²⁺radius.The luminous intensity of Y_1.94BaAl₄SiO₁₂:0.06Ce³⁺at 150?is relative to its room temperature intensity 93.32%,excellent thermal stability makes the phosphor can be used for high-power white LED.By analyzing the change in the structural rigidity of the phosphors of Y_3-xM_xAl_5-xSixO₁₂:0.06Ce³⁺?M=Ba,Sr,Ca,Mg,x=0.2,0.4,0.6,0.8,1.0?,the mechanism of the improvement of thermal stability is explained for further fluorescence,the powder performance optimization design provides theoretical reference value.?5?The microscopic morphology of Y_1.94MAl₄SiO₁₂:0.06Ce³⁺?M=Ba,Sr,Ca,Mg?phosphor under the doping condition of 1mol of M²⁺-Si⁴⁺was studied.Y_1.94MAl₄SiO₁₂:0.06Ce³⁺?M=Ba,Sr,Ca,Mg?The color coordinate shift law of the phosphor and the color coordinate shift at 25-200?.As the radius of the doped metal ion decreases gradually,the color coordinate shifts toward the red region.?6?Study the linear shrinkage of Y_3-xM_xAl_5-xSixO₁₂:0.06Ce³⁺?M=Ba,Sr,Ca,Mg,x=0.2,0.4,0.6,0.8,1.0?series phosphors,Y_1.94MAl₄SiO₁₂:0.06Ce³⁺?M=Ba,Sr,Ca,Mg?For M=Mg,the linear shrinkage is about 19.86%,for M=Ca,the linear shrinkage is about 19.66%,for M=Sr,the linear shrinkage is about 20.86%,for M=Ba,the linear shrinkage is 17.93%,and for pure YAG:Ce³⁺,the linear shrinkage is 1.40%.Obviously,the linear shrinkage of Y_1.94MAl₄SiO₁₂:0.06Ce³⁺?M=Ba,Sr,Ca,Mg?phosphor is much larger than that of YAG:Ce³⁺.The significant linear shrinkage indicates that Y_1.94MAl₄SiO₁₂:0.06Ce³⁺?M=Ba,Sr,Ca,Mg?is very likely to form a dense transparent ceramic under vacuum sintering.