Luminescence of SrAl<sub>2</sub>O<sub>4</sub>:Eu<sup>2+</sup>, Dy<sup>3+</sup> Ceramics Synthesized at Different Firing Condition

The green SrAl 2 O 4 :Eu 2+ , Dy 3+ phosphor is a well-known persistent material for a wide region of applications such as lighting, traffic signs, interior decoration and medical application. Double activated SrAl 2 O 4 :Eu 2+ , Dy 3+ with improved properties has been synthesized through solid state route at different firing atmospheres (reduction, vacuum, oxygen and CO 2 wet gas) and heating times (1 h to 8 h). At the beginning the powders were heat treated for 2 h with a heating rate of 10°C/min. The phosphor prepared at different firing atmospheres and heating times exhibited a different wavelength and intensity of PL spectra. The emission intensity becomes stronger as the heating times increases from 1 h to 4 h. The difference found from these spectra maxima is rationalized based on the presence of intermediate phases and also on the diffusion activities of activator and co-activator in the host matrices.