1 shows the XRD patterns of the SrAl2O4:Dy3+ phosphors prepared at 600, 700 and 800 °C. The data of the monoclinic SrAl2O4 (JCPDS card no. 34-0379) are depicted at the bottom of Fig. 1 for comparison. The three dominant peaks in each of the XRD curves are located at 19.98, 29.22 and 35.00°. A comparison of the data in Fig. 1 reveals that the diffraction peaks of the three kinds of SrAl2O4:Dy3+ phosphors match with those of the standard monoclinic SrAl2O4.