Study On The Structure And White Light Emission Performance Of Two Different Aluminate-based Phosphors

Existing phosphors for white LEDs have problems such as insufficient luminous efficiency and chromatism.The new material phosphors can improve the defects of existing phosphors and at the same time make an in-depth study of their luminous mechanism.In this paper,two aluminates of different structures,LaSrAl₃O₇ and Sr₃YAl₂O_7.5,were selected as the substrates,and their structures and luminescence characteristics were investigated.Phosphors with adjustable color up to white light emission were prepared by the single and double doping of rare earth ions Eu³⁺and Tb³⁺.By gel-combustion method to obtain the teteral phase structure LaSrAl₃O₇ and the hypoxic perovskite structure Sr₃YAl₂O_7.5.It was found that the structures of the two were different,but they could emit blue light under the excitation of ultraviolet light,which laid a foundation for the realization of white light emission with a single substrateSeries of Eu³⁺/Tb³⁺doped LaSrAl₃O₇ phosphors and metal ions K⁺/Mg²+/Ca²⁺/Bi³⁺doped LaSrAl₃O₇:6%Eu³⁺,2%Tb³⁺phosphors were prepared by gel-combustion method.The structure and luminescence properties of LaSrAl₃O₇-base phosphors were studied under different calcination temperature,pH and C/M ratio.The results showed that the calcination temperature,pH and C/M ratio had significant effects on the luminous intensity of the phosphor.After optimizing the experimental conditions,the optimal conditions for the preparation of pure single-phase LaSrAl₃O₇ phosphors were selected,such as 800?,pH=3,and C/M=1.2:1.Red phosphors with high luminous intensity were obtained by Eu³⁺doping at15%,and green phosphors with high luminous intensity were obtained by Tb³⁺doping at 12%.Eu³⁺and Tb³⁺were co-doped in LaSrAl₃O₇ matrix.Under the excitation of 268 nm ultraviolet light,color regulation and white light emission were realized,and energy transfer was found between Eu³⁺and Tb³⁺.The doping amount of Tb³⁺was controlled by 2%,and the doping amount of Eu³⁺was adjusted by 4%⁸%to obtain a series of phosphors emitting white light.The optimal color coordinate was?0.364,0.344?.The effect of metal ions on the properties of phosphors was investigated by adding different metal ions.It was found that the doping of K⁺/Mg²⁺had little effect on the luminescence color of LaSrAl₃O₇:6%Eu³⁺,2%Tb³⁺phosphors and had little effect on their intensity,while Ca²⁺/Bi³⁺not only enhanced their luminescence intensity,but also had an effect on their luminescence color.Series of Eu³⁺/Tb³⁺doped Sr₃YAl₂O_7.5 phosphors and metal ions K⁺/Mg²⁺/Ca²⁺/Bi³⁺doped Sr₃YAl₂O_7.5:4%Eu³⁺,1%Tb³⁺phosphors were prepared by gel-combustion method.The composition and luminescence properties of Sr₃YAl₂O_7.5 phosphors were studied under different calcination temperatures,pH and C/M conditions.The results showed that different calcination temperature,pH and C/M ratio had significant effects on the luminescence intensity of the phosphors.Through the analysis of the experimental data,the roasting temperature was 850?,pH=5,and C/M=2.0:1 were selected as the best conditions for preparing phosphors,and the pure phase material with good crystal shape was obtained.The Eu³⁺doping amount was 17%to obtain the orange phosphors with high luminous intensity,and the Tb³⁺doping amount was 7%to obtain the green phosphors with high luminous intensity.Eu³⁺and Tb³⁺were co-doped in Sr₃YAl₂O_7.5matrix.Under the excitation of 263 nm ultraviolet light,color regulation and white light emission were realized,and there was energy transfer between Eu³⁺and Tb³⁺.The doping amount of Tb³⁺was controlled by 1%,and the doping amount of Eu³⁺was adjusted by 4%⁷%.The optimal coordinate is?0.331,0.339?.In order to improve the emission intensity of Sr₃YAl₂O_7.5:x%Eu³⁺,y%Tb³⁺phosphor powder and color regulation in a wider range,metal ions K⁺/Mg²⁺/Ca²⁺/Bi³⁺were added.The doping of the four metal ions enhanced the luminescence intensity of Sr₃YAl₂O_7.5:4%Eu³⁺and 1%Tb³⁺,but had little effect on the luminescence color and remained in the white light region.In this paper,two kinds of aluminate-based phosphors with different structures,LaSrAl₃O₇ and Sr₃YAl₂O_7.5.It enriches the research of aluminate inthe field of luminescence and provides the theoretical basis for the realization of white light emission with a single substrate.