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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
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Depuru, Shobha Rani
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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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Spectroscopic investigation and local structure of Eu3+ ions in lead phosphate glasses for optical device applications
(2024-04-01)
Basavapoornima, Ch
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Masthanaiah, E.
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Vijaya, N.
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Depuru, Shobha Rani
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Kaewkhao, J.
Phosphate-based glasses are promising materials which are being employed for broad range of applications whereas Eu3+ is an efficient activator due to its predominant 5D<inf>0</inf> →7F<inf>2</inf> emission (red region). In this direction, an attempt has been made to investigate the effect of Eu3+ ions doped lead phosphate glasses (PPbKANEu: P<inf>2</inf>O<inf>5</inf>+PbO+K<inf>2</inf>O+Al<inf>2</inf>O<inf>3</inf>+Na<inf>2</inf>O+Eu<inf>2</inf>O<inf>3</inf>) to explore possible photonic device applications. Optical absorption, excitation, photoluminescence and decay rates are used to characterize the PPbKANEu glasses. The photoluminescence spectrum of Eu3+:PPbKAN glasses exhibit emission channels from the first excited (5D<inf>0</inf>) to the ground (7F<inf>J</inf> (J =0–4)) multiplets. To determine the local site symmetry of surrounding Eu3+ ions, the relative fluorescence intensity ratio of 5D<inf>0</inf>→7F<inf>1</inf> versus 5D<inf>0</inf>→7F<inf>2</inf> emission channels has been analyzed. The emission spectrum of PPbKANEu glasses exhibits a comprehensive lifting of degeneracy of 5D<inf>0</inf>→7F<inf>2</inf> and 5D<inf>0</inf>→7F<inf>1</inf> emission channels. By considering C<inf>2v</inf> symmetry for Eu3+ ions, the second (B<inf>0</inf>2= −406 and B<inf>2</inf>2=−158) and fourth (B<inf>0</inf>4=980, B<inf>2</inf>4=297 and B<inf>4</inf>4=926 cm–1) rank crystal–field (CF) characteristics were estimated along with CF strength factor (S= 402 cm–1). The lifetime of 5D<inf>0</inf> state is estimated to be 2.09, 2.23, 2.21 and 2.21 ms for 0.1, 0.5, 1.0 and 2.0 mol% of Eu3+ ions, respectively. The analysis of the decay times reveals that the lifetime of 5D<inf>0</inf> state is less affected by the concentration of the Eu3+ ion. The results are compared and discussed with reported values and confirm the potentiality of the PPbKANEu glasses for optical device applications in visible regions.
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Investigation of structural, optical and luminescence characteristics of Dy3+-embedded alkaline heavy metal zincfluoroborophosphate glasses
(2024-03-01)
Basavapoornima, Ch
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Chandrappa, V.
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Kesavulu, C. R.
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Lokanadham, R.
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Pecharapa, Wisanu
Dy3+-embedded glasses have been widely considered for light-emitting diode applications as well as optical display devices. Based on this importance, the present study investigates the structural and photoluminescence characteristics of Dy3+-embedded zincfluoroborophosphate glasses. These glasses with molar composition of 35H<inf>3</inf>BO<inf>3</inf> + 10NH<inf>4</inf>H<inf>2</inf>PO<inf>4</inf> + 25BaCO<inf>3</inf> + (5 − N)La<inf>2</inf>O<inf>3</inf> + 25ZnF<inf>2</inf> + NDy<inf>2</inf>O<inf>3</inf> (BPBaLaZfDy<inf>N</inf>), where N = 2.0, 1.0, 0.5, 0.1, and 0.05, were fabricated by the melt and quenching procedure. FTIR spectra show the existence of fundamental groups such as BO<inf>3</inf> and BO<inf>4</inf> units, phosphates as well as OH groups. The criterion of metallization, optical electronegativity and basicity of the fabricated glasses was investigated and presented. The three phenomenological Judd–Ofelt (JO) parameters were estimated with the aid of optical absorption of oscillator strengths by using well-known theoretical JO model and in turn estimated the essential radiative characteristics of excited fluorescent states of Dy3+ ion. Dy3+:BPBaLaZfDy glasses reveal the luminescence levels at 840 nm (infrared: 4F<inf>9/2</inf> → 6H<inf>7/2</inf>), 754 nm (infrared: 4F<inf>9/2</inf> → 6H<inf>9/2</inf>), 664 nm (weak red: 4F<inf>9/2</inf> → 6H<inf>11/2</inf>), 485 nm (blue: 4F<inf>9/2</inf> → 6H<inf>15/2</inf>) and 576 nm (yellow: 4F<inf>9/2</inf> → 6H<inf>13/2</inf>), exciting at 350 nm. Among different concentrations, 0.5 mol% (BPBaLaZfDy<inf>0.5</inf>) glass exhibits relatively more intense emission for 4F<inf>9/2</inf> → 6H<inf>15/2</inf>,<inf>13/2,11/2</inf> transitions. From emission data, colour chromaticity coordinates, yellow/blue emission intensity ratio, colour purity and correlated colour temperatures have been determined. The decay times for BPBaLaZfDy glasses were measured with 350 nm excitation and noticed that the radiative de-excitation from 4F<inf>9/2</inf> → 6H<inf>13/2</inf> state. The fluorescence lifetime values decrease (659 μs to 389 μs) with increase (0.05 to 2.0 mol%) in Dy3+ content. The analysis of the present work confirms the preference of BPBaLaZfDy glasses for the fabrication of optical display components as well as white light luminescence devices.
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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
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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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Photoluminescence characteristics of Ln3+-doped phosphors derived from sustainable resources for solid state lightning applications
(2022-08-01)
Reddappa, R.
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Devi, L. Lakshmi
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Basavapoornima, Ch
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Depuru, Shobha Rani
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Kaewkhao, J.
Di-calcium silicate (Ca<inf>2</inf>SiO<inf>4</inf>) phosphors doped with series of Ln3+ ions have been prepared by using high temperature solid-state reaction technique. The required raw chemicals of CaO from egg shell and SiO<inf>2</inf> from rice husk powders have been used instead of chemicals which were derived from non-renewable minerals. The structural, morphological and photoluminescence characteristics were studied through XRD, SEM and FLS 980 spectrometer measurements, respectively. The XRD patterns of all the phosphors are fit well with the established ICDD card No.01–083–0464 with monoclinic crystal structure. Photoluminescence spectra of Ce3+, Pr3+, Sm3+, Eu3+, Tb3+, Dy3+ and Er3+-doped phosphors exhibit characteristic sharp intense emission peaks at 385 (d-f), 606 (1D<inf>2</inf>→3H<inf>4</inf>), 600 (4G<inf>5/2</inf>→6H<inf>7/2</inf>), 703 (5D<inf>0</inf>→7F<inf>4</inf>), 544 (5D<inf>4</inf>→7F<inf>5</inf>), 573 (4F<inf>9/2</inf>→6H<inf>13/2</inf>) and 545 nm (4S<inf>3/2</inf>→4I<inf>15/2</inf>), respectively. Emission characteristics of developed phosphors such as CIE co-ordinates, correlated colour temperature, colour purity, lifetimes of fluorescent level, etc., of Ln3+ have been quantified. The decay curves for lower concentrations of Ln3+ ion exhibit single exponential behaviour and turns into bi-exponential behaviour accompanied with shortening in lifetime for higher concentrations. These results have been discussed with reported values and found to be better than many of the reported phosphors derived from non-renewable minerals. Therefore, Ca<inf>2</inf>SiO<inf>4</inf>:Ln3+ phosphors could also be useful to design and develop low-cost solid state lightning devices besides effective utilization of renewable agricultural and food waste materials.
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Spectral characteristics of Pr3+-doped lead based phosphate glasses for optical display device applications
(2020-12-01)
Basavapoornima, Ch
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Kesavulu, C. R.
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Maheswari, T.
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Pecharapa, Wisanu
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Depuru, Shobha Rani
The present work concentrates on spectral analysis of Pr3+:lead phosphate (PPbKANPr) glasses for visible lasers and optical amplifier applications and these glasses were prepared by a melt-cast technique. Vibrational modes of PPbKANPr glasses have been analyzed through FTIR and Raman techniques. Based on the absorption spectrum and the renowned Judd-Ofelt (JO) formalism, the three JO parameters (Ω<inf>2,4,6</inf>) were calculated and then used to estimate the various radiative probabilities for characteristic excited fluorescent states of Pr3+. The derived JO parameters ( × 10−20 cm2) were found to be Ω<inf>2</inf> = 1.51, Ω<inf>4</inf> = 18.03 and Ω<inf>6</inf> = 19.81. The luminescence spectra exhibit emission bands in the visible region of 480–780 nm and with the increase of Pr3+ ion concentration, the emission intensities were decreased due to concentration quenching. The decay curves of the PPbKANPr glasses were measured with the 443 nm excitation, monitoring via the luminescence peak at 610 nm. The decay rates reveal bi-exponential trend with shortening of lifetimes with increasing of Pr3+ ion concentration. Near infrared luminescence properties were obtained with the excitation of Ar+ ion laser line (488 nm) and the spectrum consists of three emission bands covering from 800 nm to 1600 nm. The investigation of the results proved that the current PPbKANPr glasses are useful for visible lasers and optical amplifiers.
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Spectral characteristics of Pr3+-doped lead phosphate glasses for optical display device and gain media applications
(2020-10-26)
Basavapoornima, Ch
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Maheswari, T.
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Kesavulu, C. R.
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Pecharapa, W.
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Kaewkhao, J.
The present work is concentrated on spectral analysis of Pr3+-doped lead phosphate (PPbKANPr) glasses for visible lasers and optical amplifier applications where the PPbKANPr glasses were prepared by a melt quenching technique. Based on the absorption spectrum and the well-known Judd-Ofelt (JO) theory, the JO intensity parameters were determined and then used to calculate the various radiative parameters for higher excited luminescent states of Pr3+ ion. The derived JO parameters (× 10-20 cm2) were found to be ω2 = 1.51, ω4 = 18.03 and ω6 = 19.81. The luminescence spectra exhibit emission bands in the visible region of 480-780nm and with the increasing of Pr3+ ion concentration, the emission intensities were decreased due to concentration quenching. The analysis of the results confirms that the PPbKANPr glasses are useful for visible lasers as well as optical amplifiers.

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