Study On Preparation And Photoluminescence Characteristics Of Aluminates And Aluminates-Silicate Long Afterglow Materials

Long afterglow phosphor is a kind of pigment that absorbs energy and then releases the stored energy in the form of light after being excited. In the recent years, long afterglow phosphor has attracted much interest, especially for the aluminates MAl₂O₄(M: Ca, Sr, Ba) dopped by Eu²⁺. Compared with single pigment that emit homochromatic light, such as SrAl₂O₄:Eu, Dy(green light), CaAl₂O₄:Eu, Nd(blue light), MgSiO₃:Mn(red light), the complexes might emit different colour light which could enlarge the bound of the wavelength.The blue-emitting long persistent phosphor CaAl₂O₄:Eu, Nd and the green-emitting long persistent phosphor SrAl₂O₄:Eu, Dy was prepared by combustion synthesis. The influence of Eu concentration, the ratio of Nd(Dy)/Eu, urea concentration and H3BO₃ as flux on its luminescence was investigated. With the work above, we make sure the available condition to synthesize the phosphors.We try to clad the red luminescent powder phosphors MgSiO₃:Mn on the surface of CaAl₂O₄:Eu, Nd and SrAl₂O₄:Eu, Dy with sol-gel method. The ratio of CaAl₂O₄:Eu, Nd(SrAl₂O₄:Eu, Dy)/MgSiO₃:Mn, the time of adding the CaAl₂O₄:Eu, Nd, the ratio of Mg/Si, the concentration of Mn²⁺ on its luminescence was studied. In addition, the pigment mixed with CaAl₂O₄:Eu, Nd(SrAl₂O₄:Eu, Dy) and MgSiO₃:Mn was prepared as contrast. The synthesis, luminescent properties, fluorescence mechanism and afterglow characteristics of phosphors were investigated by the means of XRD, Emission spectra, Excitation spectra, Decay curve and so on.Composite material with weak blue phosphors and strong red phosphors was prepared. But another composite material was only emit red phosphors without green one.