Photoluminescence Properties of Eu2+, Dy3+, Li+ Co-doped CaSi2O2N2 Phosphors

A series of CaSi2O2N2: 0.05Eu2+, xDy3+, xLi+ (0≤x≤0.03) phosphors were prepared through high-temperature solid-state reaction method. The phosphors were characterized by X-ray diffraciton (XRD) and fluorescence spectrophotometer (PL). XRD patterns revealed that the samples maintained CaSi2O2N2 single phase after doping Dy3+ or Li+ ions. The PL results showed that the excitation spectra of samples were all located in the UV to blue spectral region. The emission spectra for 400 nm excitation showed the typical broad band of Eu2+ peaking at about 545 nm (5d-4f). In addition, the emission intensity could be greatly enhanced through doping Dy3+ in CaSi2O2N2:Eu2+ phosphors. Furthermore, the effect of the Li+ doping was studied. Li+ ions could be used as charge compensation in CaSi2O2N2:Eu2+, Dy3+ phosphors. Thus the doping of Li+ ions could further improve the emission intensity of CaSi2O2N2:Eu2+, Dy3+ phosphor. When the doping concentrations of Dy3+ and Li+ were 1mol%, the emission intensity reached a maximum, which was about 157% of that of the sample without doping Dy3+ or Li+.