White light emitting Sr3YNa(PO4)3F: Dy3+, Eu3+ fluorapatite phosphor with tunable correlated color temperature

Dy3+ and Eu3+ doped Sr3YNa(PO4)(3)F fluorapatite phosphors were synthesized using a solid-state reaction method. The structural, morphological and luminescence properties of the individually doped and codoped phosphors were studied. The photoluminescence (PL) spectra of Sr3YNa(PO4)(3)F: Eu3+ phosphor showed red emission lines due to the 4f-4f transitions, while that of Sr3YNa(PO4)(3)F: Dy3+ phosphor showed dual emissions in the blue and yellow regions. Although Dy3+-emissions are supposed to produce white light emission, the quality of the white light is compromised due to the poor color rendering index (CRI) occurring from the absence of the red component. This issue was addressed by codoping Eu3+ and Dy3+ ions in the Sr3YNa(PO4)(3)F host and achieving emission lines in the blue, yellow and red regions of the visible light spectrum. By tuning the Dy3+/Eu3+ concentration ratios, the correlated color temperature (CCT) of the white light was tuned from cool-white to warm-white. Moreover, the codoping of Dy3+ and Eu3+ resulted in improving the CRI of the phosphor. The results suggest that Sr3YNa(PO4)(3)F: Dy3+, Eu3+ phosphor is a potential candidate for solid-state lighting applications.