Concentration influence on temperature-dependent luminescence properties of samarium substituted strontium tetraborate

Photoluminescence and Visible Diffuse-Reflection Spectroscopic Evidence of Samarium Reduction in Air-Fired Samples of Mixed Samarium: Strontium Tetraborate Precipitates

“…2) precludes assignment of any single phase product. The only structurally related statement that can be made is that the emission features exhibited by these samples (including the sample prepared without strontium) seem to indicate that the divalent samarium occupies a site that is consistent throughout this series and is identical to that reported in the literature 5,9,–16 for samarium-doped strontium tetraborate. This uniformity of the metal-ion site is confusing in that the general structure associated with these compositions is not known to be consistent.…”

“…The emission spectrum exhibited by every sample composition is consistent with that reported previously for ceramic preparations of divalent samarium in strontium tetraborate. 1,5,9,–16 Nearly all previous reports did not consider absorption or diffuse-reflection spectroscopy to study the resulting samarium-ion valences associated with these compounds, but instead they relied solely upon emission or excitation spectroscopy. The exception to this trend is a recent report by Sakirzanovas et al 11 This study reported the use of diffuse-reflection spectra to study 0.1, 1, and 10 mole percent samarium doped into strontium tetraborate samples prepared by the ceramic method.…”

“…The compounds formed between strontium and several polyborates have become of interest owing to their ability to stabilize divalent forms of various lanthanide and actinide elements even when fired in air. 1,–11 Lanthanide and actinide elements predominantly exhibit trivalent oxidation states. Exceptions to this general rule provide interesting anomalies from which much information can be gleaned, in addition to unusual chemical, electrical, and optical characteristics that can be exploited.…”

“…Nearly all previous methods of preparation of divalent rare-earth-doped strontium polyborates 1,–16 have involved the solid-state or ceramic reaction of strontium carbonate, the lanthanide or actinide oxide, and boric acid, often under a reducing atmosphere. Instead of a solid-state reaction of the mixed components, it is suggested that the sample could be precipitated homogeneously from an aqueous solution as a tetraborate hydrate.…”

THERMO LUMINESCENCE STUDY OF SrB4O7: Cu PHOSPHOR PREPARED BY COMBUSTION SYNTHESIS

“…Borate systems have proved to be potential candidates for aforementioned applications 1 . The orthorhombic phase of strontium tetra borate SrB 4 O 7 compound has attracted attention owing to its interesting physical properties, namely an unprecedented fundamental optical-absorption edge among oxide compounds (~130 nm), high nonlinear optical coefficients 2-4 , good luminescent characteristics and an ability to stabilize rare-earth elements in divalent state 5 .…”