Significant Variations in the Luminescence of Samarium(II) Doped Strontium and Barium Octaborate as a Function of Excitation Wavelength and Sample Temperature

Abstract

The emission features characteristic of divalent samarium formed in samarium-doped barium octaborate (BaB₈O₁₃) and strontium borate (Sr₂B₁₆O₂₆) have been studied as a function of excitation wavelength and sample temperature. The emission spectra of divalent samarium in both materials exhibit a surprisingly strong temperature dependence. When divalent samarium is doped into BaB₈O₁₃, changes in excitation wavelength and sample temperature both result in significant variations in the emission features associated with the material. It is therefore hypothesized that the variation arises primarily from selected excitation of individual samarium sites within the BaB₈O₁₃ matrix. The emission features characteristic of divalent samarium in Sr₂B₁₆O₂₆, also exhibited significant variation as the sample temperature was lowered, but this variation was irrespective of the excitation wavelength. This appears to indicate dependence solely on competition between de-excitation pathways.