Sol-gel synthesis and the effect of boron addition on the phosphorescent properties of SrAl₂O₄:Eu²⁺,Dy³⁺phosphors

The effects of boron addition on the microstructure and afterglow properties of the long-phosphorescent SrAl₂O₄:Eu²⁺,Dy³⁺(SAED), synthesized via a novel sol-gel route, were systematically investigated. Significant improvement on luminescence intensity and the lengthening of afterglow persistent time in boron-added SAED (BSAED) phases were observed, as compared to those without boron addition and commercial phosphors. Typical bluish-green emissions attributed to the doublet phosphorescence with wavelengths peaking at 412 and 501 nm for BSAED phase and 398 and 486 nm for the pristine SAED phase were observed. Afterglow with wavelengths peaking at 403 and 485 nm was observed for BSAED phase, whereas that with wavelengths peaking at 486.5 nm was found for the pristine SAED phase, as indicated by time-dependent afterglow decay profiles. Results from scanning electron microscopic morphological studies were used to investigate the modification of microstructure of the BSAED phases.