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AIP Conference Proceedings [AIP Publishing PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS: ICAM 2019 - Kerala, India (12–14 June 2019)] PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS: ICAM 2019 - Structural and optical studies of bismuth silicate oxyfluoride glasses for LED applications
摘要： The samples SBS20, SBS25 and SBS30 are prepared by traditional melt quenching method. The XRD pattern of prepared samples confirms the glassy nature and a broad peak at 2θ=280. The Raman spectra indicate that addition of SrF2 into the glass matrix leads to loosening of network. It will create more non- bridging oxygen in the samples. The Absorption spectra shows two peaks at 466 nm and 499 nm due to Bi2+ in different environments. The absorption edge shifted to lower wavelength with lower content of Bi2O3 due to the less amount of Bi3+ ion in the glass matrix. Optical band gap increases from 2.84eV to 2.86eV with increasing the SrF2 content leads to loosening of network. Emission spectra consist of three peaks at 435 nm, 510 nm and 630 nm, blue region is arising from Bi3+ and other two are from Bi2+. 20SBS and 25SBS show white light whereas 30SBS shows yellowish green in CIE diagram. The color purity and correlated color temperature are also calculated.
关键词： optical studies,structural studies,LED applications,bismuth silicate oxyfluoride glasses
更新于2025-09-12 10:27:22
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AIP Conference Proceedings [AIP Publishing PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS: ICAM 2019 - Kerala, India (12–14 June 2019)] PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS: ICAM 2019 - Photoluminescence study of (Sm0.95 Ce0.05)2O3 nanoparticles for LED applications
摘要： Nanophosphors are a blazing area which has gained momentum in the present day research due to the fabulous unique properties of nanoparticles from their respective bulk. The rare earth doped sesquioxides have received considerable attention due to its unique properties like high chemical and thermal stabilities, intense UV absorption and also its use in solid state lightings, LASERS and so on. Here, we have synthesized (Sm0.95 Ce0.05)2O3 nanocrystalline powder using combustion method. Powder X-ray diffraction was used to study the structural characterization of the synthesized sample and the result confirmed that the synthesized nanoparticles had a nanocrystalline structure with a cubic phase and ? space group. The crystal structure and the shape of the particles have a tremendous effect on the photoluminescent properties. The surface morphology and the size of the particles were examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The SEM micrographs showed that the synthesized particles appear to be spherical. The TEM results confirmed that the particles formed were spherical and in nano regime. Phosphors with spherical morphology will surely enhance the photoluminescent properties of the materials. Hence the synthesized sample will have good luminescent characteristics. The optical properties of the sample were studied using ultraviolet –visible (UV-Vis) data analysis and photoluminescence (PL) studies. The absorption peaks obtained are at 364nm, 376, 405, 464 nm and 476nm which correspond to 6H5/2 → 4D3/2, 6H5/2 → 4D1/2, 6H5/2 → 6F7/2, 6H5/2 → 4I13/2 and 6H5/2 → 4I11/2 transitions respectively. On excitation, these particles showed a strong emission at 605 nm which corresponds to 4G5/2 →6H7/2 transition and other emissions at 563 nm and 647nm correspond to 4G5/2 →6H5/2 and 4G5/2 →6H5/2 transitions revealing that it is an orange-red emissive phosphor. This novel nanophosphor can offer new possibilities for the development of white light-emitting diodes (WLEDs) which can be excited by the near-UV chips and also in solid state lightings.
关键词： combustion method,LED applications,photoluminescence,Nanophosphors,(Sm0.95 Ce0.05)2O3
更新于2025-09-11 14:15:04