Preparation And Properties Of Y_xGd_(1-x)BO₃:Eu³⁺ Luminescent Materials

Rare earth borate has high vacuum ultraviolet transmittance and excellent optical damage threshold.It is a very good luminescent matrix.In addition,the B-O chemical bond in borate ion has a variety of coordination modes,which makes the borate can be excited by different light sources,and the structure of the borate is stable,so it is very suitable as a matrix material.Eu³⁺has a simple energy level structure and electronic configuration capacity,and is easily excited by external energy to emit better monochromatic light,so Eu³⁺is often used as an activator for phosphors.With borate as the matrix Eu³⁺as the activator,phosphors with stable luminescence performance can be synthesized.Rare earth borate phosphors have good stability and good luminous performance,mercury-free fluorescent lamps,plasma flat panel displays(PDP)and so on.Among the red phosphors,YBO₃:Eu³⁺and Gd BO₃:Eu³⁺arethemost commonly used borate-based phosphors.The luminescence performance of these two phosphors is not ideal,so how to improve the luminescence performance of rare earth borate phosphors has attracted much attention.This paper mainly studies the effects of composite matrix rare earth borate phosphors and non-rare earth metal cations on their luminescence properties.In order to improve the photoluminescence intensity and quantum efficiency,a composite matrix Y_xGd_(1-x)BO₃:Eu³⁺phosphors were prepared by hydrothermal method,and the prepared composite matrix phosphor was treated with non-rare earth metal Ions Mⁿ⁺(K⁺,Li⁺,Al³⁺,Mg²⁺)doping.The quantum efficiency,phase composition,surface morphology and luminescence intensity of the phosphor were analyzed by characterization methods such as PL,XRD and SEM,and the effect of different metal ions on its luminous efficiency under different doping amounts was studied.The specific content and conclusions of the research are as follows:(1)When the molar ratio of Y³⁺:Eu³⁺is 20:1 and the molar ratio of Gd³⁺:Eu³⁺is 20:1,the luminous intensity and quantum efficiency of YBO₃:Eu³⁺phosphor and Gd BO₃:Eu³⁺phosphor are significantly higher than other ratios Reached the maximum value.Therefore,20:1 was the best doping ratio of host ion to Eu³⁺to prepare composite matrix Y_xGd_(1-x)BO₃:Eu³⁺phosphor.(2)Y_xGd_(1-x)BO₃:Eu³⁺phosphors prepared with different values of x belong to the hexagonal crystal system and have a hexagonal structure.When x is 0.6,Y_xGd_(1-x)BO₃:Eu³⁺phosphors had the best photoluminescence performance.Compared with YBO₃:Eu³⁺and Gd BO₃:Eu³⁺phosphors,the photoluminescence intensity was increased by 39.47%and 75.77%,respectively.The quantum efficiency increased by 60.53%and 93.11%,respectively.And both of them show a trend of first increasing and then decreasing with the increase of the value of x.(3)Y_0.6Gd_0.4BO₃:Eu³⁺:Mⁿ⁺phosphor doped with different metal cations Mⁿ⁺(K⁺,Li⁺,Mg²⁺,Al³⁺)regardless of the amount of metal cation doped,Y_0.6Gd_0.4BO₃:Eu³⁺:Mⁿ⁺fluorescence The powder belongs to the hexagonal crystal system and has a hexagonal structure,and its main morphology is spherical particles composed of flake structures.(4)The luminescence performance of Y_0.6Gd_0.4BO₃:Eu³⁺:Mⁿ⁺phosphor after doping with metal cations K⁺,Li⁺,Mg²⁺was improved compared with that before undoping.When the doping amount of K⁺is 1%,Y_0.6Gd_0.4BO₃:Eu³⁺:K⁺phosphors had the best luminescence performance.Compared with before undoped,the quantum efficiency and luminous intensity was increased by 49.83%and 55.73%,respectively.When the doping amount of Li⁺is 1%,the Y_0.6Gd_0.4BO₃:Eu³⁺:Li⁺phosphors had the best luminescence performance.Compared with before undoped,the quantum efficiency and luminous intensity was increased by 13.95%and 5.78%,respectively.When the doping amount of Mg²⁺is 1%,Y_0.6Gd_0.4BO₃:Eu³⁺:Mg²⁺phosphor had the best luminous performance.Compared with before undoped,the quantum efficiency and luminous intensity was increased by 21.37%and 25.12%,respectively.(5)After Al³⁺doping,the luminescence performance of Y_0.6Gd_0.4BO₃:Eu³⁺:Al³⁺phosphors is worse than before without doping regardless of the amount of Al³⁺doping.However,the quantum efficiency and luminous intensity of Y_0.6Gd_0.4BO₃:Eu³⁺:Al³⁺phosphors increase first and then decrease with the increasing amount of Al³⁺doped.When the doping amount of Al³⁺is5%,Y_0.6Gd_0.4BO₃:Eu³⁺:Al³⁺phosphor has the best luminescence performance,but its quantum efficiency and luminous intensity are still reduced by 15.87%and 14.52%.In summary,the borate composite matrix phosphor prepared by the hydrothermal method has good crystallization properties,and appropriate non-rare earth metal ions can improve its luminescence performance.