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Optical and emission Spectroscopy and radiation shielding properties of Sm3+-Doped P2O5 + BaO + La2O3 glasses
(2026-01-01)
Kesavulu, C. R.
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Masthanaiah, E.
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Basavapoornima, Ch
;
Depuru, Shobha Rani
;
Pecharapa, Wisanu
Within lanthanide series, Sm3+(4f5) ion is relatively very complex electronic structure and similar to Dy3+(4f9) ion but both ions exhibit visible and infrared emissions. As such, characteristics (structural, thermal, optical, luminescence, etc.) of Sm3+ ion doped crystals, glass-ceramics, phosphors and glasses have been widely investigated for development of visible photonic devices, scintillators and magnetic components. In this paper, studies carried out so far on physical, structural, luminescence and optical characteristics of Sm3+-embedded glasses have been collected, tabulated and re-analysed in a systematic procedure besides our own work on P<inf>2</inf>O<inf>5</inf> + BaO + La<inf>2</inf>O<inf>3</inf> + Sm<inf>2</inf>O<inf>3</inf> (PBaLaSm) glasses. All the quantified properties have also been reviewed besides the labeling of glass compositions in a meaningful way. The properties that are reviewed include, optical energy gap, Judd-Ofelt (JO), radiative, etc. The obtained JO parameters ( × 10−20 cm2) for the present glasses are Ω<inf>2</inf> = 5.57, Ω<inf>4</inf> = 5.22 and Ω<inf>6</inf> = 3.37. In the case of Sm3+ ion, it has been noticed that the JO analysis found to be not only sensitive to the co-ordination geometry of the surrounded glass composition but also on the number of absorption levels that are used for the JO analysis. Theoretical radiation shielding results for the studied glass found to be better than the RS-253-G18, RS-360, lead and ordinary concrete at 30 and 40 KeV. The decay rates for 4G<inf>5/2</inf> level of Sm3+ ions in the PBaLaSm glasses have been measured and are found to exhibit single exponential nature at lower concentration and turns into non-exponential at higher concentrations (≥1.0 mol % Sm<inf>2</inf>O<inf>3</inf>-doped glasses). The experimental lifetimes for 4G<inf>5/2</inf> level of Sm3+ ions are found to decrease from 2413, 2383, 2129, 2039, 1299 and 259 μs when concentration increases from 0.01, 0.05, 0.1,0.5, 1.0 and 2.0 mol % due to cross-relaxation energy transfer. The non-exponential decay rates are well-fitted to Inokuti-Hirayama model for S = 6, indicates that the energy transfer is of dipole-dipole type. However, the overall observations outlined in this study for 48 Sm3+:glasses may be quite useful for those who are interested in this thrust area to plan and carryout systematic study to get constructive conclusion besides predictive nature.
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Structural, optical, luminescence spectroscopy and radiation shielding properties of Eu3+:borophosphotellurite glasses
(2024-10-01)
Masthanaiah, E.
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Basavapoornima, Ch
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Lokanadham, R.
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Pecharapa, Wisanu
;
Kaewkhao, J.
Recently much effort is being paid to study the rare earth ions in multi component glass formers as they exhibit high enhancement in the efficiency of luminescence properties. In this direction, the present study focuses on the preparation and analysis of novel glass batches with composition of (in mol %) BPTCZEu: 40B<inf>2</inf>O<inf>3</inf>+20P<inf>2</inf>O<inf>5</inf>+15TeO<inf>2</inf>+ 10CaO+(15−x)ZnO + xEu<inf>2</inf>O<inf>3</inf>, x = 0.1, 0.5, 1.0, 1.5, 2.0 and 2.5. The important spectroscopic techniques such as optical absorption, luminescence, excitation and decay curves are taken to analyse the BPTCZEu glasses. Luminescence spectrum of BPTCZEu comprise of emission from excited (5D<inf>0</inf>) to the lower multiplets (7F<inf>J</inf> (J = 0−4)), among these, 5D<inf>0</inf> → 7F<inf>2</inf> (red luminescence) at 612 nm found to be very intense. Judd−Ofelt characteristics, Ω<inf>2</inf>, Ω<inf>4</inf> and Ω<inf>6</inf>, were derived from different constraints. To know the site symmetry around Eu3+, the fluorescence intensity ratio of 5D<inf>0</inf> → 7F<inf>2</inf> vs. 5D<inf>0</inf> → 7F<inf>1</inf> were analysed. Exciting 7F<inf>0</inf> → 5L<inf>6</inf> and monitoring 5D<inf>0</inf> → 7F<inf>2</inf>, the lifetime of 5D<inf>0</inf> level is determined to be 2 ms which is independent of Eu3+ content. The colour coordinates for all the Eu3+ concentrations are estimated to fall in the reddish−orange region. Theoretical radiation shielding results showed that substituting Eu<inf>2</inf>O<inf>3</inf> for ZnO in the glasses lowers photon number that can pass via the material, enhancing the glass system's trend to shield high energy radiation. These stimulated results are compared with experimental measurements of mass attenuation coefficient with respect to energy up to 662 KeV using Cs−137 source. All these findings obtained from title glasses are compared and discussed with respect to reported Eu3+:glasses and no systematic variation has been noticed either with single, bi− or multi−component glass formers and therefore needs further systematic work to relate Eu−radiation−ligand interaction.
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A critical review and future prospects of Dy3+-doped glasses for white light emission applications
(2022-09-01)
Chandrappa, V.
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Basavapoornima, Ch
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Venkatramu, V.
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Depuru, Shobha Rani
;
Kaewkhao, J.
Rare-earth (RE)-doped glassy systems gained much interest because of its wide variety of applications in numerous potential fields that include optical fibers, solid state lasers, optical amplifiers, optical thermometry sensors, waveguides, infrared detectors, spectral converters, display devices, and so on. Within RE ions, the trivalent dysprosium (Dy3+) ion is the most unique and characteristic ion to examine emission properties for white light and visible display emitting devices. Because, Dy3+ ion emits two intense emissions in the blue (~480 nm) and yellow (~575 nm) regions that are assigned to the 4F<inf>9/2</inf>→6H<inf>15/2</inf> and 4F<inf>9/2</inf>→6H<inf>13/2</inf> transition energies, respectively. Under the excitation of blue laser, Dy3+ ions exhibit attractive yellowish white fluorescence emission with higher quantum efficiency. In view of the importance of identifying efficient luminescent emitting materials for the development of optical devices, the present work is to investigate white light emission in new glass composition of B<inf>2</inf>O<inf>3</inf> +TeO<inf>2</inf> +SrCO<inf>3</inf> +ZnO+ZnF<inf>2</inf> +Dy<inf>2</inf>O<inf>3</inf> glass and in turn to compare and discuss these results with reported Dy3+:glasses. The tabulated reported data bank for 68 Dy3+:glasses at one place should prove valuable information for future work on rationalization of theoretical and practical point of view to enrich white light emission quantification, simulation and systemization.

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