Luminescence properties and energy-transfer behavior of Y_2-x-yBi_xEu_yMgTiO₆ phosphors

In recent years, double perovskite has become a research hotspot of luminescent matrix materials due to its flexible structure, easy doping and good thermal stability. By using a high temperature solid-state technique, Bi³⁺ and Eu³⁺ co-doped Y_2-x-yBi_xEu_yMgTiO₆ (0 ≤ x ≤ 0.1, 0 ≤ y ≤ 0.5) phosphors were made. X-ray diffraction (XRD) analysis shows that the crystal structure of all samples is monoclinic system, P2₁/n; Bi³⁺ and Eu³⁺ can be doped into the position of Y³⁺ in the substitution system of Y₂MgTiO₆. Both photoluminescence spectroscopy (PL) and X-ray excitation luminescence spectroscopy (XEL) were used to investigate the link between Bi³⁺ and Eu³⁺ doping concentrations and luminescence intensity. PL shows that: When 375 nm is used as the excitation wavelength, by varying the doping concentration of Eu³⁺ in the Y_1.995-yBi_0.005Eu_yMgTiO₆ phosphor, it is possible to create the color-tunable emission from blue to red; The introduction of an appropriate amount of Bi³⁺ will increase the typical Eu³⁺ emission; The way that the system's Bi³⁺ and Eu³⁺ exchange energy can be observed by combining the fluorescence decay curve and photoluminescence. Fitting by concentration quenching model shows that the resonant dipole-dipole transition is the mechanism of energy transfer between Bi³⁺→Eu³⁺; X-rays may successfully stimulate the phosphor, and the spectral distribution of XEL and PL is basically the same; The introduction of an appropriate amount of Bi³⁺ is also beneficial to improving the sensitivity of XEL; Changes in temperature affect the sample's emission intensity; In addition, the samples remain stable for an extended period while being continuously exposed to X-rays at various environmental temperatures. The a forementioned findings suggest that the phosphor has potential use value in the lighting industry, X-ray imaging and temperature sensor.