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Blue Photoluminescence and Cyan-Colored Afterglow of Undoped SrSO₄ Nanoplates.

ABSTRACT: Undoped SrSO₄ nanoplates were synthesized via the composite hydroxide-mediated approach. The products were characterized by means of X-ray diffractometry, scanning electron microscopy, X-ray energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, photoluminescence (PL) spectroscopy, electron spin resonance technique, afterglow spectroscopy, and thermoluminescence dosimetry. The steady-state PL spectrum of undoped SrSO₄ nanoplates can be deconvoluted into two distinct Gaussian bands centered at 2.97 eV (417.2 nm) and 2.56 eV (484.4 nm), respectively. The nature of the defect emissions is confirmed through the emission-wavelength-dependent PL decays as well as the excitation-wavelength-dependent PL decays. A cyan-colored afterglow from undoped SrSO₄ nanoplates can be observed with naked eyes in the dark, and the afterglow spectrum of the undoped SrSO₄ nanoplates exhibits a peak at about 492 nm (2.52 eV). The duration of the afterglow is measured to be 16 s. The thermoluminescence glow curve of the undoped SrSO₄ nanoplates shows a peak at about 40.1 °C. The trapping parameters are determined with the peak shape method, the calculated value of the trap depth is 0.918 eV, and the frequency factor is 1.2 × 10¹⁴ s^-1. Using density functional calculations, the band structures and densities of states of oxygen-deficient SrSO₄ and strontium-deficient SrSO₄ are presented. The mechanisms of the cyan-colored afterglow are discussed for undoped SrSO₄, and the oxygen vacancies in SrSO₄ are proposed to be the luminescence center of the afterglow.

SUBMITTER: Zhai BG

PROVIDER: S-EPMC8153658 | biostudies-literature |

REPOSITORIES: biostudies-literature

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