Preparation And Luminescence Study Of Silicate Phosphor With Oxy-apatite Structure Applied In White Light Emitting Diode

In this paper, divalent europium doped oxyapatite-structure oxy-silicate phosphors with general chemical formula, Mx-yRE10-x(SiO4)6O3-x/2:Eu2+y(M=Mg, Ca, Sr, Ba; Ln=Y, La, Gd), were successfully prepared by high temperature solid state method under (N2+H2) atmosphere. The effect of firing temperatures, Eu2+ concentration, alkaline earth and rare earth metal cations on the phase structure and luminescence propertity were studied by XRD, SEM and photoluminescence spectra. The results show that the phosphors could be excited by wavelengths extended from 260 to 500 nm. Only one emission peak was observed in the emission spectra under 365 nm excitation while x<2. However, two emission peaks occurred as the content of alkaline earth metal increasing. And the reasons were discussed. While x>2, the relative intensity of emission peak with shorter wavelength decreased while the one with longer wavelength increasing, as the concentration of europium increased. The varieties of alkaline earth and rare earth metals could both affect the positions and the relative intensities of emission peaks.Nitridized alkaline earth-rare earth silicate phosphors were successfully synthesized under NH3 atmosphere based on oxy-apatite. The phase structure, luminescence properties and morphology were charactered by XRD, FT-IR, reflection spectra, photoluminescence spectra and SEM. And the contents of oxygen and nitrogen were analyzed by an O-N analyser. According to the results, the phosphors maintain oxy-apatite structure after nitidization. However, obviously red shifts were observed both in the excitation and emission spectra, and both of the varieties and the contents of alkaline earth and rare earth elements influence the emission spectra.