Fig. 10

(a) The PL excitation spectra of synthesized Na₂Ca₄(PO₄)₃F: Dy³⁺/Tb³⁺ phosphor with different varying concentration located at emission 545 nm. Figure 10. (b-d) The PL emission spectra of synthesized Na₂Ca₄(PO₄)₃F: Dy³⁺/Tb³⁺ phosphor with different varying concentration located at excitation b) 351 nm, c) 365 nm, d) 378 nm.