TOF SIMS analysis and generation of white photoluminescence from strontium silicate codoped with europium and terbium

White light emitting terbium (Tb³⁺) and europium (Eu ³⁺) codoped strontium silicate (Sr₂SiO₄) phosphors were prepared by a solid state reaction process. The structure, particle morphology, chemical composition, ion distribution, photoluminescence (PL), and decay characteristics of the phosphors were analyzed by x-ray diffraction (XRD), scanning electron microscopy (SEM), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and PL spectroscopy, respectively. The XRD data showed that our Sr₂SiO₄ composed of two phases, namely, β-Sr₂SiO₄ and α′-Sr ₂SiO₄, and the α′-Sr₂SiO ₄ phase was more prominent than the β-Sr₂SiO ₄ phase. The SEM micrographs showed that the particles were agglomerated together and they did not have definite shapes. All ions (i.e., negative and positive) present in our materials were identified by TOF-SIMS. In addition, the chemical imaging performed with the TOF-SIMS demonstrated how the individual ions including the dopants (Eu³⁺ and Tb³⁺) were distributed in the host lattice. White photoluminescence was observed when the Sr₂SiO₄:Tb³⁺, Eu³⁺ phosphor was excited at 239 nm using a monochromatized xenon lamp as the excitation source. The phosphor exhibited fast decay lifetimes implying that it is not a good candidate for long afterglow applications.