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Start date: 2020Subject: search.filters.subject.optical properties

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    Optimization of Pr3+-doped glasses for photonic applications: an overview and challenges in Judd–Ofelt analysis
    (2026-07-17)
    Kesavulu, C. R.
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    Soumya, S.
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    Saikia, Darshana
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    Jayasankar, Deviprasad Chalicheemalapalli
    ;
    Pecharapa, Wisanu
    Characteristics (optical, luminescence, up-conversion, etc.) of triply ionized Praseodymium (Pr<sup>3+</sup>) ions doped glasses, glass-ceramics, phosphors and crystals have been widely studied for the development of photonic devices. Most of these characteristics are mainly based on Judd–Ofelt (JO) theory to interpret transition intensities and in turn to simulate radiative properties of Pr<sup>3+</sup> ions based optical materials. However, JO analysis provides inconsistent results for Pr<sup>3+</sup>:glasses. Further, besides no review is available focusing on uneven findings of Pr<sup>3+</sup>:glasses. Therefore, a comprehensive data on Pr<sup>3+</sup>:glasses have been collected (490 Pr<sup>3+</sup>:glasses) and compared, besides labeling glass compositions systematically. The properties that are reviewed include, Nephelauxetic effect, optical energy gap, thermal, JO parameters, radiative properties, etc. It has been noticed that the systematic study either in preparation or optimization of characteristic properties are very much missing. Moreover, large number of data sets of literature are presented at one place which is very much useful for predictive modeling approaches. Also, the primary focus of the present review is not to provide a comprehensive summary of all studies conducted so far or to discuss new findings, but rather to highlight the challenges associated with JO parameters for Pr<sup>3+</sup> ions that influence the development of optical materials, components, and applications.
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    Tailoring the Emission Behavior of WO3 Thin Films by Eu3+ Ions for Light-Emitting Applications
    (2023-01-01)
    Kavitha, V. S.
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    Biju, V.
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    Gopchandran, K. G.
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    Praveena, R.
    ;
    Jayasankar, C. K.
    The article reports the successful fabrication of Eu<sup>3+</sup>-doped WO<inf>3</inf> thin films via the radio-frequency magnetron sputtering (RFMS) technique. To our knowledge, this is the first study showing the tunable visible emission (blue to bluish red) from a WO<inf>3</inf>:Eu<sup>3+</sup> thin film system using RFMS. X-ray diffractograms revealed that the crystalline nature of these thin films increased upto 3 wt% of the Eu<sup>3+</sup> concentration. The diffraction peaks in the crystalline films are matched well with the monoclinic crystalline phase of WO<inf>3</inf>, but for all the films’, micro-Raman spectra detected bands related to WO<inf>3</inf> monoclinic phase. Vibrational and surface studies reveal the amorphous/semi-crystalline behavior of the 10 wt% Eu<sup>3+</sup>-doped sample. Valence state determination shows the trivalent state of Eu ions in doped films. In the 400–900 nm regions, the fabricated thin films show an average optical transparency of ~51–85%. Moreover, the band gap energy gradually reduces from 2.95 to 2.49 eV, with an enhancement of the Eu<sup>3+</sup>-doping content. The doped films, except the one at a higher doping concentration (10 wt%), show unique emissions of Eu<sup>3+</sup> ions, besides the band edge emission of WO<inf>3</inf>. With an enhancement of the Eu<sup>3+</sup> content, the concentration quenching process of the Eu<sup>3+</sup> ions’ emission intensities is visible. The variation in CIE chromaticity coordinates suggest that the overall emission color can be altered from blue to bluish red by changing the Eu<sup>3+</sup> ion concentration.
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    Optical Properties of CuCdS Thin Film Prepared by Vacuum Thermal Evaporation Technique
    (2023-01-01)
    Hankoy, Montree
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    Treetornkeerati, Paramapat
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    Fungfuang, Natasia
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    Khlayboonme, S. Tipawan
    ;
    Kitiwan, Mettaya
    This study reports on the synthesis and characterizations of copper cadmium sulfide (CuCdS) thin films prepared using the vacuum thermal evaporation technique with copper sulfide and CdS as precursors in a 1:1 molar ratio. The structural properties of the thin films were analyzed using X-ray diffraction (XRD) which revealed that the main composition of the thin film was CdS with the preferred orientation of the (101) plane. The optical properties were examined using UV–Vis spectrophotometry. The photosensitivity of the films was determined using I–V measurements performed with a two-probe technique. The prepared CuCdS thin films have high optical transmittance of 92%.
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