Correlated color temperature tunability and energy transfer phenomenon in the NaBaBO3:Dy3+/Eu3+ phosphor for white light application

NaBa0.97-xBO3 0.03Dy(3+), xEu(3+) (0 <= x <= 0.09) single-phase white phosphors with tunable correlated color temperature (CCT) were synthesized using a conventional solid state reaction method. The phase structure and luminescence properties of the as-prepared samples were investigated. The Dy3+, Eu3+ doped and Dy3+/Eu3+ co-doped NaBaBO3 phosphors excited by 361 nm show two blue and yellow emissions corresponding to the F-4(9/2) -> H-6(15/2) and F-4(9/2) -> H-6(13/2) transitions of Dy3+ ions and two red emissions due to the D-5(0) -> F-4(J) (J = 1, 2) transitions of Eu3+ ions. Under 361-nm light excitation, the NaBa0.97-xBO3 0.03Dy(3+), xEu(3+) (0 <= x <= 0.09) phosphors feature a white light emitting property. Through the Commission Internationale de L'Eclairage (CIE) chromaticity analysis and CCT calculation, the CIE chromaticity coordinates of the emission light are all located in the white region and can be tuned from bluish white light to reddish white light when the Eu3+ concentration increases, and the CCT values of the obtained samples can vary from 5514.31K to 8269.42 K. Furthermore, the energy transfer phenomenon from Dy3+ ions to Eu3+ ions in Dy3+/Eu3+ co-doped samples was also investigated. The results indicated that, through tuning the Eu3+ concentration of the NaBaBO3:Dy3+/Eu3+ phosphors, the NaBaBO3-based phosphor can act as a potential single-phase white emitting phosphor for the application in the near-ultraviolet (NUV) white light emitting diodes.