Luminescence Studies of rare-earth Ce~(3+) and Dy~(3+) doped SrAl_2O_4 aluminate phosphors

摘要

The rare-earth doped Sr_(0.96)Ce_(0.04-x)Dy_xAl_2O_4 [x = 0.03, 0.02, 0.01] aluminate phosphors synthesized by the high temperature solid-state reaction route are reported in this work. The phosphors under investigation were characterized for the structural and luminescence properties. The structural studies were carried out exploiting X-ray diffraction, Raman scattering technique, and the Fourier transform infrared spectroscopy. The optical study of the phosphors under observation comprises UV-Vis, thermoluminescence, and photoluminescence studies. The XRD results of these materials on analysis revealed that the samples exhibit double phase where dominating phase is that of desired Sr_(0.96)Ce_(0.04-x)Dy_xAl_2O_4 [x = 0.03, 0.02, 0.01] phosphors with trace of secondary phase arising from unreacted SrCO_3. The Sr_(0.96)Ce_(0.04-x)Dy_xAl_2O_4 [x = 0.03, 0.02, 0.01] alumi-nates have acquired the monoclinic phase (P1 21 n) and SrCO3 was found to have crystalized into the orthorhombic (Pmcn) phase. The characteristic Raman band at around ≈ 460 cm~(-1) for Sr_(0.96)Ce_(0.01)Dy_(0.03)Al_2O_4 phosphor conveys the monoclinic structure in the sample. The UV-Vis spectral studies revealed the optical bandgap around 3 eV. Thermoluminescence study inferred the optimum intensity for 25-min exposure to the excitation radiation with higher intensity for x = 0.02 (Dy/Ce) concentration. The photoluminescence studies revealed the emission in the blue region for x = 0.03 and 0.02 confirmed from the CIE coordinate values and near red emission in the higher concentrated Ce~(3+) ions.