Structural and morphological characterization of photoluminescent cerium-doped near UV-blue sodium ortho-phosphate phosphors

Cerium (Ce³⁺) doped sodium ortho-phosphate (NaMPO₄) (M = Mg, Ca, Sr or Ba) were synthesized using solution combustion method. The phosphors were analyzed using X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), Energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, UV–vis spectroscopy and photoluminescence (PL) spectroscopy. As confirmed from the XRD data, NaCaPO₄ and NaBaPO₄ crystallized in an orthorhombic phase, while NaMgPO₄ and NaSrPO₄ crystallized in a monoclinic phase. The SEM data showed that the particle morphology was influenced by alkaline earth metal ions. The PL data exhibited broad emission bands with different emission maxima in the energy range of 2.7–4.2 eV, i.e. in the near UV-blue region of the electromagnetic wave spectrum. The difference in the PL emission spectra that is associated with crystal field effect and other factors is discussed.