<p>Phosphor materials play a crucial role in the advancement of optical technologies. In this study, SrAl<sub>4</sub>O<sub>7</sub>:xGd<sup>3+</sup> (<i>x</i> = 0.01–0.11&#xa0;mol) phosphors are synthesized using the combustion method, and their structural, morphological, and optical properties are examined. X-ray diffraction analysis confirms that the phosphors crystallize in the monoclinic <i>C</i>2/<i>c</i> space group. Photoluminescence spectroscopy indicates well-defined intra-configurational 4f–4f transitions of Gd<sup>3+</sup> ions, with prominent emission peaks at 308&#xa0;nm and 314&#xa0;nm, corresponding to the <sup>6</sup>P<sub>5/2</sub> → <sup>8</sup>S<sub>7/2</sub> and <sup>6</sup>P<sub>7/2</sub> → <sup>8</sup>S<sub>7/2</sub> transitions, respectively. The luminescence intensity is optimized at a Gd<sup>3+</sup> concentration of 0.09&#xa0;mol. The electron paramagnetic resonance spectra of SrAl<sub>4</sub>O<sub>7</sub>:Gd<sup>3+</sup> phosphors exhibit a prominent resonance line at an effective <i>g</i>-factor of approximately 1.97, accompanied by weaker signals in the low-field region. Two distinct Gd<sup>3+</sup> sites with differing local environments contribute to the observed spectrum. These environmental variations arise from charge-compensating Sr<sup>2+</sup> vacancies or interstitial O<sup>2−</sup> ions and their proximity to Gd<sup>3+</sup> ions. The findings highlight the potential of Gd<sup>3+</sup>-doped SrAl<sub>4</sub>O<sub>7</sub> for advanced UV photonic applications, particularly in dermatological phototherapy, where precise control over emission properties is crucial.</p>

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Photoluminescence and EPR Study of the Local Environment of Gd3+ in SrAl4O7 UVB Phosphors

  • Vijay Singh,
  • MOHD Musaib Haidari,
  • Ji Bong Joo,
  • S. Watanabe,
  • T. K. Gundu Rao

摘要

Phosphor materials play a crucial role in the advancement of optical technologies. In this study, SrAl4O7:xGd3+ (x = 0.01–0.11 mol) phosphors are synthesized using the combustion method, and their structural, morphological, and optical properties are examined. X-ray diffraction analysis confirms that the phosphors crystallize in the monoclinic C2/c space group. Photoluminescence spectroscopy indicates well-defined intra-configurational 4f–4f transitions of Gd3+ ions, with prominent emission peaks at 308 nm and 314 nm, corresponding to the 6P5/2 → 8S7/2 and 6P7/2 → 8S7/2 transitions, respectively. The luminescence intensity is optimized at a Gd3+ concentration of 0.09 mol. The electron paramagnetic resonance spectra of SrAl4O7:Gd3+ phosphors exhibit a prominent resonance line at an effective g-factor of approximately 1.97, accompanied by weaker signals in the low-field region. Two distinct Gd3+ sites with differing local environments contribute to the observed spectrum. These environmental variations arise from charge-compensating Sr2+ vacancies or interstitial O2− ions and their proximity to Gd3+ ions. The findings highlight the potential of Gd3+-doped SrAl4O7 for advanced UV photonic applications, particularly in dermatological phototherapy, where precise control over emission properties is crucial.