Abstract: A series of Eu³⁺ singly- and Dy³⁺/Eu³⁺ co-doped CaLaGa₃O₇ single matrix phosphors were successfully prepared by high-temperature solid-phase method. The phase and luminescence properties of the samples were characterized by X-ray diffraction (XRD) and photoluminescence spectra. The XRD patterns show that all the prepared samples have a tetragonal structure consistent with the matrix crystal, indicating the successful synthesis of that Eu³⁺ singly- and Dy³⁺/Eu³⁺ co-doped CaLaGa₃O₇ phosphors. Under excitation of 393 nm, Eu³⁺∶CaLaGa₃O₇ exhibits characteristic red emission of Eu³⁺ (⁵D₀→⁷F₂), and the luminescence purity is as high as 100%. After introducing Dy³⁺, Dy³⁺/Eu³⁺ co-doped CaLaGa₃O₇ phosphors could be excited not only by 393 nm light but also by 348 nm. Regardless of the excitation wavelength, the emission spectra of Dy³⁺/Eu³⁺∶CaLaGa₃O₇ include both the characteristic red emission of Eu³⁺ and the yellow emission of Dy³⁺ (⁴F_9/2→⁶H_13/2). By analyzing the emission spectra and fluorescence lifetime, it is confirmed that there exists effective energy transfer process between Dy³⁺ and Eu³⁺ in the co-doped phosphors. Further, the corresponding chromaticity coordinates and CCT values were calculated. The results show that the overall chromaticity coordinates shift from the yellow-green region to the yellow-orange region when the excitation wavelength is changed from 348 nm to 393 nm. Therefore, the Dy³⁺/Eu³⁺∶CaLaGa₃O₇ is a tunable luminescent material with good application prospects in displays and solid-state lighting.

Key words: CaLaGa₃O₇, Dy³⁺/Eu³⁺ co-doping, phosphor, luminescence property, color tunable, high-temperature solid-phase method