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<p>The Ln<sup>3+</sup> doped K<sub>6-3x</sub>Ln<sub>x</sub>Na<sub>3</sub>Al<sub>3</sub>(PO<sub>4</sub>)<sub>6</sub>(KNAPO-Ln); (Ln = Eu<sup>3+</sup>, Dy<sup>3+</sup> and Sm<sup>3+</sup>; 0.0 ≤ x ≤ 0.125) phosphors were prepared by well-known high temperature solid state reaction. The as prepared compositions were characterized by different techniques. The prepared powders were crystallized in the monoclinic lattice with space group P2<sub>1</sub>/c. Well-crystallized particles of phosphors exhibited irregular morphology with particle sizes of 5 – 20&#xa0;μm. The FT-IR profiles of the compositions gave characteristic bands belonging to vibrational modes of orthophosphate (PO<sub>4</sub>) group. The PL profiles of KNAPO: Eu<sup>3+</sup> compounds are characterized by four emission bands centred at 589 (<sup>5</sup>D<sub>0</sub> → <sup>7</sup>F<sub>1</sub>), 616 (<sup>5</sup>D<sub>0</sub> → <sup>7</sup>F<sub>2</sub>), 652 (<sup>5</sup>D<sub>0</sub> → <sup>7</sup>F<sub>3</sub>) and 701 (<sup>5</sup>D<sub>0</sub> → <sup>7</sup>F<sub>4</sub>) nm with 394&#xa0;nm (<sup>7</sup>F<sub>0</sub> → <sup>5</sup>L<sub>6</sub>) excitation wavelength. The KNAPO: Dy<sup>3+</sup> compounds gave a weak blue emission at 483&#xa0;nm (<sup>4</sup>F<sub>9/2</sub> → <sup>6</sup>H<sub>15/2</sub>) and a strong yellow emission at 574&#xa0;nm (<sup>4</sup>F<sub>9/2</sub> → <sup>6</sup>H<sub>13/2</sub>) with excitation at 350&#xa0;nm (<sup>6</sup>H<sub>15/2</sub> → <sup>6</sup>P<sub>7/2</sub>). The KNAPO: Sm<sup>3+</sup>compositions gave four emission peaks at 564 (<sup>4</sup>G<sub>5/2</sub> → <sup>6</sup>H<sub>5/2</sub>), 600 (<sup>4</sup>G<sub>5/2</sub> → <sup>6</sup>H<sub>7/2</sub>), 646 (<sup>4</sup>G<sub>5/2</sub> → <sup>6</sup>H<sub>9/2</sub>) and 711 (<sup>4</sup>G<sub>5/2</sub> → <sup>6</sup>H<sub>11/2</sub>) nm upon excitation at 404&#xa0;nm. The variation in emission intensity with Ln<sup>3+</sup> concentration was studied and found that the concentration quenching was dominant for compositions in which the value of x is higher than 0.05 (Dy)/0.075 (Eu, Sm). The CIE chromaticity coordinates / correlated color temperature(K) / color purity(%) of K<sub>5.775</sub> Eu<sub>0.075</sub> Na<sub>3</sub>Al<sub>3</sub>(PO<sub>4</sub>)<sub>6,</sub> K<sub>5.85</sub> Dy<sub>0.05</sub> Na<sub>3</sub>Al<sub>3</sub>(PO<sub>4</sub>)<sub>6</sub> and K<sub>5.775</sub> Sm<sub>0.075</sub>Na<sub>3</sub>Al<sub>3</sub>(PO<sub>4</sub>)<sub>6</sub> are (0.606, 0.356/1830 K/78.3%), (0.368, 0.366/4277 K/20.2%) and (0.574, 0.423/1760&#xa0;K/65.1%) respectively. The TL profiles of Eu, Dy and Sm doped KNAPO samples are characterized by a single peak maximum in the 350 – 390 °C range and trap depth parameters were evaluated. These compositions may be useful in the manufacturing of cool and warm solid state lighting sources.</p>

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Preparation, characterization, PL and TL of Rare-Earth activated K6Na3Al3(PO4)6 phosphor

  • 期刊论文

  • 发表日期：

    2026年6月27日

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  • Putta Shekar,
  • Muga Vithal,
  • Mudavat Srinivas

摘要

The Ln3+ doped K6-3xLnxNa3Al3(PO4)6(KNAPO-Ln); (Ln = Eu3+, Dy3+ and Sm3+; 0.0 ≤ x ≤ 0.125) phosphors were prepared by well-known high temperature solid state reaction. The as prepared compositions were characterized by different techniques. The prepared powders were crystallized in the monoclinic lattice with space group P21/c. Well-crystallized particles of phosphors exhibited irregular morphology with particle sizes of 5 – 20 μm. The FT-IR profiles of the compositions gave characteristic bands belonging to vibrational modes of orthophosphate (PO4) group. The PL profiles of KNAPO: Eu3+ compounds are characterized by four emission bands centred at 589 (5D0 → 7F1), 616 (5D0 → 7F2), 652 (5D0 → 7F3) and 701 (5D0 → 7F4) nm with 394 nm (7F0 → 5L6) excitation wavelength. The KNAPO: Dy3+ compounds gave a weak blue emission at 483 nm (4F9/2 → 6H15/2) and a strong yellow emission at 574 nm (4F9/2 → 6H13/2) with excitation at 350 nm (6H15/2 → 6P7/2). The KNAPO: Sm3+compositions gave four emission peaks at 564 (4G5/2 → 6H5/2), 600 (4G5/2 → 6H7/2), 646 (4G5/2 → 6H9/2) and 711 (4G5/2 → 6H11/2) nm upon excitation at 404 nm. The variation in emission intensity with Ln3+ concentration was studied and found that the concentration quenching was dominant for compositions in which the value of x is higher than 0.05 (Dy)/0.075 (Eu, Sm). The CIE chromaticity coordinates / correlated color temperature(K) / color purity(%) of K5.775 Eu0.075 Na3Al3(PO4)6, K5.85 Dy0.05 Na3Al3(PO4)6 and K5.775 Sm0.075Na3Al3(PO4)6 are (0.606, 0.356/1830 K/78.3%), (0.368, 0.366/4277 K/20.2%) and (0.574, 0.423/1760 K/65.1%) respectively. The TL profiles of Eu, Dy and Sm doped KNAPO samples are characterized by a single peak maximum in the 350 – 390 °C range and trap depth parameters were evaluated. These compositions may be useful in the manufacturing of cool and warm solid state lighting sources.