THERMOLUMINESCENCE STUDIES OF SrAl2O4: Eu PHOSPHORS AT DIFFERENT DY CONCENTRATIONS

Sr(NO3)2, Al(NO3)3, NH2CONH2, Eu2O3 and Dy2O3 are used as the raw materials for the preparation of SrAl2O4 (RE: Eu, Dy) precursor by the combustion synthesis technique (CST), which is widely known to prepare nano sized phosphors. The influence of varied concentration of Dy on crystal structure and optical properties is analyzed by means of Xray diffraction (XRD), scanning electron microscopy (SEM) and thermoluminescence (TL) spectra. The fine flake-like phosphors with reasonable good brightness and long afterglow are obtained by treating the samples at different temperatures. XRD patterns reveal a dominant phase characteristics of the monoclinic SrAl2O4 compound and the presence of dopants having uncognizable effect on the basic crystal structure of SrAl2O4. From XRD studies, the average particle size of the flake-like SrAl2O4: Eu, Dy phosphors is calculated to be nearly 12 nm. The optical properties in terms of TL glow curves are studied and discussed systematically. The results indicate that the peak positions in the spectra are not much affected by varying concentration of Dy. The different parameters like activation energy, frequency factor and shape factor are calculated using TL glow curves.