NaBa 0.97-x BO 3 0.03 Dy 3+, x Eu 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 Dy 3+, Eu 3+ doped and Dy 3+/ Eu 3+ co-doped NaBaBO 3 phosphors excited by 361 nm show two blue and yellow emissions corresponding to the 4 F 9/2 → 6 H 15/2 and 4 F 9/2 → 6 H 13/2 transitions of Dy 3+ ions and two red emissions due to the 5 D 0 → 4 F J (J = 1, 2) transitions of Eu 3+ ions. Under 361-nm light excitation, the NaBa 0.97-x BO 3 0.03 Dy 3+, x Eu 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 Eu 3+ concentration increases, and the CCT values of the obtained samples can vary from 5514.31 K to 8269.42 K. Furthermore, the energy transfer phenomenon from Dy 3+ ions to Eu 3+ ions in Dy 3+/ Eu 3+ co-doped samples was also investigated. The results indicated that, through tuning the Eu 3+ concentration of the NaBaBO 3: Dy 3+/ Eu 3+ phosphors, the NaBaBO 3-based phosphor can act as a potential single-phase white emitting phosphor for the application in the near-ultraviolet (NUV) white light emitting diodes.
Chromaticity Study of Curcumin Dye Extracted from Curcuma longa L. Using for UV Light down Conversion for White Light Emitting Diode
