Scholarlink

<p>A series of white light emitting dysprosium activated lanthanum hydroxide nanophosphors have been synthesized via microwave-assisted co-precipitation method and the structural, morphological, thermal and optical properties are examined. The formation, crystallinity and phase purity of Dy<sup>3+</sup> doped La(OH)<sub>3</sub> were confirmed by XRD. The observed diffraction patterns aligned with the standard ICDD database, confirming crystallization in hexagonal structure with space group <i>P</i>6<sub>3</sub>/<i>m</i> and the average crystallite size computed using the Scherrer equation was found to be 20.5&#xa0;nm. The distinct vibrational modes associated with the hydroxyl groups in La(OH)<sub>3</sub> were identified through FTIR analysis. Thermal analysis demonstrated the decomposition pathways of lanthanum hydroxide to the sesquioxide form. SEM and TEM analysis were done to assess the aggregated morphology of the sample and the particle size is estimated to be in the nanometer regime as evident from the TEM image. HRTEM displays high crystallinity with well defined lattice fringes having separation of 3.16&#xa0;Å, corresponding to the most intense X- ray diffraction peak. Excitation spectrum delineates peaks in NUV/UV as well as in blue region. The photoluminescence emission spectra of all the samples exhibit two prominent peaks in blue (475&#xa0;nm) and yellow (571&#xa0;nm) regions corresponding to <sup>4</sup>F<sub>9/2</sub> → <sup>6</sup>H<sub>15/2</sub> and <sup>4</sup>F<sub>9/2</sub> → <sup>6</sup>H<sub>13/2</sub> respectively. The optimum concentration was found to be x = 0.06, beyond which the photoluminescence intensity diminishes and the critical distance for concentration quenching is determined to be 13.08&#xa0;Å. The CIE values specify colour coordinates spanning from bluish white to near white and CCT value of 6045&#xa0;K indicate cool white emission from the prepared phosphor. The study reveals La<sub>(1−x)</sub>Dy<sub>x</sub>(OH)<sub>3</sub> as a potential candidate for UV/NUV excited white LEDs.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Cool white light emitting La(1−x)Dyx(OH)3 nanophosphors: microwave driven co-precipitation and luminescence studies

  • 期刊论文

  • 发表日期：

    2025年1月3日

查看全文
  • Jifi Jose,
  • Sajan Thomas,
  • Bibily Baby,
  • Ann V. Lizbathu,
  • Neekha Deen Abraham,
  • P. R. Biju,
  • Cyriac Joseph

摘要

A series of white light emitting dysprosium activated lanthanum hydroxide nanophosphors have been synthesized via microwave-assisted co-precipitation method and the structural, morphological, thermal and optical properties are examined. The formation, crystallinity and phase purity of Dy3+ doped La(OH)3 were confirmed by XRD. The observed diffraction patterns aligned with the standard ICDD database, confirming crystallization in hexagonal structure with space group P63/m and the average crystallite size computed using the Scherrer equation was found to be 20.5 nm. The distinct vibrational modes associated with the hydroxyl groups in La(OH)3 were identified through FTIR analysis. Thermal analysis demonstrated the decomposition pathways of lanthanum hydroxide to the sesquioxide form. SEM and TEM analysis were done to assess the aggregated morphology of the sample and the particle size is estimated to be in the nanometer regime as evident from the TEM image. HRTEM displays high crystallinity with well defined lattice fringes having separation of 3.16 Å, corresponding to the most intense X- ray diffraction peak. Excitation spectrum delineates peaks in NUV/UV as well as in blue region. The photoluminescence emission spectra of all the samples exhibit two prominent peaks in blue (475 nm) and yellow (571 nm) regions corresponding to 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 respectively. The optimum concentration was found to be x = 0.06, beyond which the photoluminescence intensity diminishes and the critical distance for concentration quenching is determined to be 13.08 Å. The CIE values specify colour coordinates spanning from bluish white to near white and CCT value of 6045 K indicate cool white emission from the prepared phosphor. The study reveals La(1−x)Dyx(OH)3 as a potential candidate for UV/NUV excited white LEDs.