Structure and luminescence property of Sr₃NbGa₃Si₂O₁₄:Tm³⁺/Dy³⁺ phosphors for white LEDs

Rare earth luminescent materials are employed in a multitude of fields, including illumination and luminescence, electronic information and biochemistry, due to their distinctive luminescent properties. This paper details the successful synthesis of a series of rare-earth ion-doped phosphors based on Sr₃NbGa₃Si₂O₁₄ via a high-temperature solid-phase reaction method. The physical phase, structure and luminescence properties of the phosphor were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectroscopy (FL), and the crystal structure, excitation and emission spectra, energy transfer mechanism, CIE colour coordinates quantum yield and thermal stability were analysed and investigated in order to understand the structural and optical properties of the phosphor. The results demonstrated that the excitation and emission spectra of the samples exhibited the typical spectrum of Dy³⁺. Furthermore, the luminescence colour of the Sr_3(0.97-y)NbGa₃Si₂O₁₄: 0.03Dy³⁺/yTm³⁺ phosphor can be controlled by modulating the doping concentration of Tm³⁺ for white light emission. The Sr_2.79NbGa₃Si₂O₁₄:0.03Dy³⁺/0.04Tm³⁺ phosphor (0.3339, 0.3369) exhibits a good degree of agreement with the standard white light point (0.333, 0.333). By calculating the normalized intensity of the phosphor at different temperatures, the results demonstrated that the emission intensity of the Sr_2.79NbGa₃Si₂O₁₄:0.03Dy³⁺/0.04Tm³⁺ phosphor at 150 degrees Celsius retained 89.9% of its initial intensity. This study has successfully demonstrated the white light emission of the Sr₃NbGa₃Si₂O₁₄:Dy³⁺/Tm³⁺ phosphor, as well as the production of a phosphor with thermal stability. This phosphor has the potential to be applied in the field of near-ultraviolet light-excited white light-emitting diode lighting.