Generation of white-light from Dy³⁺ doped Sr₂SiO ₄ phosphor

A single host lattice white light emitting Sr₂SiO ₄:Dy³⁺ powder phosphor was synthesized by solid state reaction process using a temperature of 1000 C. The structure, particle morphology, chemical composition and oxidation states, photoluminescence (PL) and decay properties of the phosphor were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy and PL spectroscopy, respectively. The objective of this study was to prepare a phosphor that can be used in white light emitting diodes. The XRD patterns showed a monoclinic structure of Sr₂SiO₄ with minor incidental secondary phases from unreacted precursors. An agglomeration of particles with irregular shapes was observed from the SEM micrographs. The PL emission spectra of the Sr₂SiO₄:Dy³⁺ phosphor excited at 350 nm consist of blue, yellow and red line emissions at 486 nm, 575 nm and 668 nm corresponding respectively to the (⁴F _9/2→⁶H_15/2), (⁴F _9/2→⁶H_13/2) and (⁴F _9/2→⁶H_11/2) transitions of Dy ³⁺. The combination of these emissions constituted white light as indicated on the Commission Internationale de L'Eclairage chromatic coordinate diagram. The decay characteristics show that the phosphor consists of a single exponential decay process.