TL and PL studies on defect-assisted green luminescence from doped strontium sulfide phosphor

Defect-assisted luminescence of Pr3+-doped SrS has been investigated and reported in this paper. The polycrystalline sample of phosphor was prepared by conventional solid-state reaction method and checked for crystallization and phase by X-ray diffraction study. The thermally stimulated luminescence studies of the phosphor samples with various activator concentrations, irradiated by a blacklight source, are conducted and show a broad single peak around 365-382 K. Computerized glow curve deconvolution tool is used to evaluate the effective trapping parameters and suggests quasi-continuous distribution of traps in the range of 0.5-0.9 eV. A critical survey on the application of first-order kinetics in the present phosphor is undertaken. Photoluminescence studies reveal three excitation bands at 287, 314, 355 nm and defect-related emission at 517, 494 nm for two concentrations of activator atoms in the present phosphor. The 314-355 nm broad excitation bands correspond to a charge transfer transition of Pr3+-S2-. (C) 2008 Elsevier B.V. All rights reserved.