Authors: S. N. | C Devaraja | R.S. Gedam
Source: Scientific Reports (article, 2025-08-01)
Field: Materials Science — Ceramics and Composites

Implications of Ho3+-ions on physical, structural, optical, and spectroscopic features of Na2O-PbO-borotellurite glass system for feasible applications in optical and laser technology A novel series of Holmium-ions doped Na<sub>2</sub>O-PbO-borotellurite glasses with composition yHo<sub>2</sub>O<sub>3</sub>+(65-y)B<sub>2</sub>O<sub>3</sub> + 15TeO<sub>2</sub> + 10Pb<sub>3</sub>O<sub>4</sub> + 10Na<sub>2</sub>O, where [Formula: see text] 0.0 to 0.5 mol% with 0.1 increment, have been prepared by the melt-quenching approach. The non-crystalline state of the synthesized glasses was validated through the XRD technique. The structural modifications and presence of borate networks (BO<sub>3</sub> and BO<sub>4</sub>), tellurite networks (TeO<sub>3</sub> and TeO<sub>4</sub>), and Pb-O links were confirmed through ATR-FTIR and Raman spectroscopic methods. The morphology and analysis of elements were performed by employing the SEM-EDX technique. The optical characterizations were studied through UV-visible spectroscopy. The transitions <sup>5</sup>I<sub>8</sub> → <sup>5</sup>G<sub>5</sub>, <sup>5</sup>G<sub>6</sub>, <sup>5</sup>F<sub>1</sub>+<sup>5</sup>G<sub>6</sub>, <sup>5</sup>F<sub>2</sub>, <sup>5</sup>F<sub>3</sub>, <sup>5</sup>S<sub>2</sub>+<sup>5</sup>F<sub>4</sub> and <sup>5</sup>F<sub>5</sub> were noted. Emission spectra of the Ho<sup>3+</sup>-ions incorporated glasses were obtained using a spectrofluorometer at an excitation wavelength of 451 nm, and they exhibit an intense peak at 678 nm in the region of red. The CCT values found [Formula: see text]4000 K imply a warm CCT. The merits of physical and optical parameters viz., molar volume, density, ion concentration, field strength, optical band gaps, refractive index, Urbach energy, steepness parameter, molar polarizability, metallization criterion, electronic oxide polarizability, optical basicity etc., were evaluated using appropriate relations and they found to be in comply with the structural modifications and optical features. The density and refractive index are found between 4.067 gcm<sup>-3</sup> to 4.193 gcm<sup>-3</sup> and 2.345 to 2.367, respectively. The energy band gaps and Urbach energy range from 3.115 eV to 3.201 eV and 0.247 eV to 0.269 eV, respectively. Optical basicity and electronic oxide polarizability range from 1.254 to 1.271 and 4.015 Å<sup>3</sup> to 4.178 Å<sup>3</sup>, respectively. Metallization criterion values range from 0.395 to 0.401. Based on structural, optical, luminescence properties, and the physical and optical parameter merits, the synthesized glasses can be suitable for optical devices, including lasers, red phosphors, and optical amplifiers. Polarizability ; Materials science ; Analytical Chemistry (journal) ; Ion ; Raman spectroscopy ; Spectroscopy ; Refractive index ; Molar volume ; Holmium ; Fourier transform infrared spectroscopy ; Laser ; Chemistry ; Optics ; Molecule ; Optoelectronics ; Physics Glass properties and applications ; Luminescence Properties of Advanced Materials ; Phase-change materials and chalcogenides