Investigation of the phosphorescence, persistent decay and structure properties of Eu2+: strontium aluminate doped with Nd3+, B3+ or Dy3.

Luminescent sources based on crystalline materials doped with transition metal or rare-earth cations are known as persistent phosphors, and they can continue to emit light even after the excitation source has disappeared. The present study aims to prepare strontium aluminate with varying weight percentages of Eu2+, RE3+ (RE = Dy3+, Nd3+, or B3+) oxides by the solid-state preparation followed by firing under active carbon at 1250 °C.The produced phosphors were examined using FTIR spectroscopy, mechano-luminescent measurement, scanning electron microscopy (SEM), and X-ray diffraction (XRD). A bulk density and apparent porosity measurement was also used to assess the impact of the firing temperature at 1250 °C. Photoluminescence characteristics were examined concerning the kind of trivalent oxides doped in strontium aluminate. The results showed that for samples containing 0.15 weight% of Eu2O3 and 0.15 weight% of RE2O3, SrAl2O4 formed with Eu+ 2, RE3+ as a single phase. However, RESr2AlO5 was formed together with a minor amount of SrAl2O4 when the Eu2O3 contents decreased at the expense of the RE2O3 contents. Additionally, it was observed that the Eu3+ was converted into Eu2+ for every sample. Every sample had porous behavior, and the bulk density was increased by the inclusion of RESr2AlO5 in addition to SrAl2O4. Transitions from the 4f6 and 5d1 configurations of the emission center (Eu2+ ions) to the 4f7 configuration result in a broad band at peaks of 517 nm in the emission spectra of all the samples. Samples containing RESr2AlO5 exhibit high phosphor color characteristics, forming red-orange phosphors encircled by green phosphor rings. Compared to samples containing Nd2O3 and B2O3, those containing Dy2O3 phosphor have the highest decay time values.