Luminescence behavior of Nd³⁺-activated soda-lime-borate glasses for solid-state lasers applications

Zaman, F.,Rooh, G.,Srisittipokakun, N.,Ruengsri, S.,Kim, H.J.,Kaewkhao, J. North-Holland 2016 Journal of non-crystalline solids Vol.452 No.-

<P>In this work, Nd3+-activated soda-lime-borate (SLBNd) glasses are prepared in a composition (65-x) B:10CaO:25Na(2)O:xNd(2)O(3) (where x = 0, 0.5, 1.0, 1.5, 2.0 and 2.5 mol%) by conventional melt-quenching technique, which is its novel study for laser application. The prepared samples are studied by absorption and near-infrared (NIR) luminescence emission spectra and decay-time analysis. The Judd-Ofelt (JO) intensity parameter, Omega(lambda) (lambda = 2,4, 6), and radiative properties of the F-4(3/2) level of Nd3+ ion are calculated from absorption spectra using JO theory. At 585-nm excitation wavelength, strong NIR emission, at 1.069 mu m, is observed corresponding to the F-4(3/2) -> I-4(11/2), for all glass samples. Decay constants are found to be decreasing with increasing Nd3+ concentration due to the energy transfer through cross-relaxation process. The stimulated-emission cross-section (cr(Xp), experimental branching ratio (beta(exp)), gain bandwidth, and quantum efficiency (eta) are measured as 4.0 x 10(-20) cm(2), 68%,1.48 x 10(-25) cm(3) and 65%, respectively. Presented results revealed that Nd3+-activated soda-lime-borate glasses could be useful for 1.06-mu m laser application. (C) 2016 Elsevier B.V. All rights reserved.</P>

Physical, structural and luminescence investigation of Eu³⁺-doped lithium-gadolinium bismuth-borate glasses for LEDs

Zaman, F.,Rooh, G.,Srisittipokakun, N.,Wongdeeying, C.,Kim, H.J.,Kaewkhao, J. Elsevier 2018 SOLID STATE SCIENCES Vol.80 No.-

<P><B>Abstract</B></P> <P>The aim of the current report is to fabricate Eu<SUP>3+</SUP>-doped glasses with the chemical composition of 50Li<SUB>2</SUB>O-15Gd<SUB>2</SUB>O<SUB>3</SUB>-5Bi<SUB>2</SUB>O<SUB>3</SUB>-(30-x)B<SUB>2</SUB>O<SUB>3</SUB>-xEu<SUB>2</SUB>O<SUB>3</SUB> (where x = 0.5, 1.0, 1.5, 2.0 and 2.5 mol%), with the help of conventional melt quenching technique. The fabricated glasses have been studied with help of physical, structural and luminescence properties for application of LEDs. The structural properties were investigated by XRD and FTIR spectra. Physical properties have been measured. Direct and indirect optical energy band gap (E<SUB>g</SUB>) have been calculated and found to be increasing with Eu<SUB>2</SUB>O<SUB>3</SUB> concentration. Luminescence spectra have been observed from photo and radioluminescence spectra and found in good agreement with each other, however the concentration quenching was not determined for the samples. The high-covalence and asymmetric nature was confirmed from Photoluminescence emission and RL emission transition as well as from the higher values of luminescence intensity ratio. The JO parameters have been found for the better performance of lasing materials. The lifetime's data have been found to be decreasing from 1.64 to 1.50 ms, which is the confirmation of energy transfer in Eu<SUP>3+</SUP> ions through cross relaxations. From the calculated properties it has been suggested that the present glass samples might be good for red-light emitting devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Li<SUB>2</SUB>O-Gd<SUB>2</SUB>O<SUB>3</SUB>-Bi<SUB>2</SUB>O<SUB>3</SUB>-B<SUB>2</SUB>O<SUB>3</SUB> glasses doped with Eu<SUP>3+</SUP> prepared. </LI> <LI> E<SUB>g</SUB> found to be increasing with Eu<SUB>2</SUB>O<SUB>3</SUB> concentration. </LI> <LI> Red emission observed from photo and radioluminescence. </LI> <LI> Asymmetric nature was confirmed PL. </LI> <LI> JO analysis was applied and found good for lasing materials. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Scintillation and luminescence characteristics of Ce³⁺doped in Li₂O-Gd₂O₃-BaO-B₂O₃ scintillating glasses

Zaman, F.,Rooh, G.,Srisittipokakun, N.,Kim, H.J.,Kaewnuam, E.,Meejitpaisan, P.,Kaewkhao, J. Pergamon 2017 Radiation physics and chemistry Vol.130 No.-

<P>Ce3+ activated Li2O-Gd2O3-BaO-B(2)O(3)glass scintillator containing neutron-capture elements (Li-7, (11)Band Gd-158)were developed by conventional melt-quenching technique. Luminescence spectra under UV and X-ray excitation showed Ce3+ ion emission due to 5d -> 44f transition at 391 nm. Energy transfer from the host glass to Ce(3+)ions were confirmed by VUV-UV and XEL spectra. The highest emission intensity of Ce(3+)ions were observed at 0.5 mol%of CeF3. For the same concentration the decay time was obtained to be 19.7 ns and their mean critical distance was calculated about 22.33 angstrom. The observed decay constants revealed that direct electron-hole capture was a dominant scintillation process in the present glass matrix. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Optical and luminescence properties of Li₂O?Gd₂O₃?MO?B₂O₃?Sm₂O₃ (MO?Bi₂O₃, BaO) glasses

Zaman, F.,Kaewkhao, J.,Rooh, G.,Srisittipokakun, N.,Kim, H.J. Elsevier Sequoia 2016 JOURNAL OF ALLOYS AND COMPOUNDS Vol.676 No.-

Spectroscopic properties of Sm<SUP>3+</SUP> ion in borate based glasses (Li<SUB>2</SUB>O?Gd<SUB>2</SUB>O<SUB>3</SUB>-MO-B<SUB>2</SUB>O<SUB>3</SUB> where MO?Bi<SUB>2</SUB>O<SUB>3</SUB>, BaO) have been investigated. Glasses are prepared by melt quenching technique and their properties are investigated using different techniques which include absorption, photoluminescence (PL), X-ray excited luminescence (XEL) spectra and decay rate analysis. Furthermore, other related physical and optical properties have been calculated. From absorption spectra the most intense and hyper sensitive transition is <SUP>6</SUP>H<SUB>5/2</SUB> → <SUP>6</SUP>P<SUB>3/2</SUB> at 403 nm. Under 403 nm excitation wavelength, four prominent emission peaks are observed at 563, 599, 645 and 707 nm. For Sm<SUP>3+</SUP> ion the quenching points are observed at 2.0 and 1.5 mol% of LGBiBSm and LGBaBSm, respectively. Measured XEL spectra of the glass samples are found in agreement with that of PL emission spectra. The experimental decay rate follows non exponential behavior at higher concentrations and well fitted to the IH model for S = 6. The obtained color coordinates of the prepared glass matrix fall in the orange region of the CIE diagram. Comparing with LGBiBSm glass, LGBaBSm is transparent and exhibits long decay time value. Moreover, LGBaBSm shows high luminescence properties with excellent energy transfer from the host matrix to the luminescence center. On the basis of the observed properties of the developed glasses, it is expected that they will be best for the orange LEDs.

Photoluminescence and white light generation of Dy₂O₃ doped Li₂O-BaO-Gd₂O₃- SiO₂ for white light LED

Khan, I.,Rooh, G.,Rajaramakrishna, R.,Srisittipokakun, N.,Wongdeeying, C.,Kiwsakunkran, N.,Wantana, N.,Kim, H.J.,Kaewkhao, J.,Tuscharoen, S. Elsevier 2019 JOURNAL OF ALLOYS AND COMPOUNDS Vol.774 No.-

<P><B>Abstract</B></P> <P>Dy<SUP>3+</SUP>-doped Li<SUB>2</SUB>O-BaO-Gd<SUB>2</SUB>O<SUB>3</SUB>-SiO<SUB>2</SUB> (LBGS) glasses were prepared by traditional melt quenching techniques and characterized through absorption and emission spectra. Tauc's plot for allowed direct and indirect transition are shown studied and observed in the range of 3.5 (eV) to 2.9 (eV). The variation in the band gap with the addition of Dy<SUB>2</SUB>O<SUB>3</SUB> is due to structural changes in the glass matrix. For 0.5 mol% of Dy<SUP>3+</SUP> ions doped LBGS glasses Judd-Ofelt analysis was carried out further these parameters were used to study their radiative properties for the excited luminescent levels of Dy<SUP>3+</SUP> ions. White light generation was evaluated as a function of the Dy<SUP>3+</SUP> ions concentration by measuring yellow-to-blue emission intensity ratios and CIE chromaticity coordinates. The non-exponential decay were observed for glasses doped beyond 0.1 mol% and were well fitted to IH-model for S = 6 (dipole-dipole interaction). The non-exponential behavior and life time quenching have been accredited to the energy transfer through dipole-dipole interaction among the excited and unexcited Dy<SUP>3+</SUP>ions. Pulse X-Ray decay time has measured for 0.5 mol% of Dy<SUP>3+</SUP> ions doped LBGS glass. CIE-1931 chromaticity coordinates and decay profile analysis were studied. The correlated color temperature (CCT) for LBGS-0.5Dy is found to be 3621 K at λ<SUB>exc</SUB> = 350 nm. The quantum efficiency (η) for the title LBGS-0.5Dy glass is found to be 74%. The highest values for radiative transition probability (A<SUB>R</SUB>), emission cross section (σ(λ<SUB>P</SUB>)), experimental and calculated branching ratio (β<SUB>R</SUB>) have been observed for <SUP>4</SUP>F<SUB>9/2</SUB> → <SUP>6</SUP>H<SUB>13/2</SUB> at 576 nm.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Oscillator strength and Judd-Ofelt (Ω<SUB>2</SUB>) parameter in the present glass is high. </LI> <LI> Tauc's plot for allowed direct and indirect transition were studied for LBGS glasses. </LI> <LI> The bonding parameter for LBGS-0.5Dy glass indicates the ionic nature of Dy<SUP>3+</SUP> ions. </LI> <LI> Yellow to blue (Y/B) ratio increase upto 0.5 mol% of Dy<SUB>2</SUB>O<SUB>3</SUB> and then start decreasing. </LI> <LI> The decay time are found to be decreasing with increase in dopant concentration. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Emission spectrum of LBGS-Dy glasses measured at room temperature.</P> <P>[DISPLAY OMISSION]</P>

Development of Li₂O-SrO-GdF₃-B₂O₃ oxyfluoride glass for white light LED application

Shamshad, L.,Rooh, G.,Kirdsiri, K.,Srisittipokakun, N.,Kim, H.J.,Kaewkhao, J. Elsevier Scientific Pub. Co 2016 Journal of molecular structure Vol.1125 No.-

Dysprosium doped Li<SUB>2</SUB>O-SrO-GdF<SUB>3</SUB>-B<SUB>2</SUB>O<SUB>3</SUB> (LSGB) glasses were prepared by the conventional melt quenching technique in order to study the luminescence properties and their utility for white light emitting diodes (LEDs). The glass structure was studied by X-ray diffraction (XRD) and Fourier transform infra-red (FT-IR) spectroscopy. XRD confirmed the amorphous structure of the glass samples. The FT-IR spectra revealed the presence of BO<SUB>3</SUB>, BO<SUB>4</SUB> and non-bridging oxygen's. The optical absorption measurement were carried out in UV-VIS-NIR region. The PL emission and excitation spectra for the LSGB glasses were investigated. From the excitation and the emission spectra the highest Dy<SUP>3+</SUP> excitation and emission intensities was observed for 0.5 mol% Dy<SUP>3+</SUP>-doped oxyfluoride glass. Strong blue (482 nm) and yellow (575 nm) emission bands were observed upon various excitations. These two emissions corresponds to the (<SUP>4</SUP>F<SUB>9/2</SUB> → <SUP>6</SUP>H<SUB>15/2</SUB>) and (<SUP>4</SUP>F<SUB>9/2</SUB> → <SUP>6</SUP>H<SUB>13/2</SUB>) transitions of Dy<SUP>3+</SUP> ions, respectively. The blending of these blue and yellow bands gives white light. The CIE 1931 chromaticity coordinates for all the as made glass samples under various excitation wavelengths lies right in white region. The calculated correlated color temperature (CCT) values for the present oxyfluoride glasses were found in the range of 4336-4299 K. These were slightly more than warm CCT (i.e., CCT<4000 K) which lies in between those of fluorescent tube (3935 K) and day light (5500 K). These results reveals the possibility of the studied glasses to be used in various photonic devices for white light generation.

Photoluminescence and white light generation behavior of lithium gadolinium silicoborate glasses

Shamshad, L.,Rooh, G.,Kirdsiri, K.,Srisittipokakun, N.,Damdee, B.,Kim, H.J.,Kaewkhao, J. Elsevier 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.695 No.-

<P><B>Abstract</B></P> <P>The Dy<SUP>3+</SUP>-doped lithium gadolinium silica borate glasses with composition (in mol%) 40Li<SUB>2</SUB>O:15Gd<SUB>2</SUB>O<SUB>3</SUB>:5SiO<SUB>2</SUB>: (40-x)B<SUB>2</SUB>O<SUB>3</SUB>:xDy<SUB>2</SUB>O<SUB>3</SUB>, x = 0.01, 0.1, 0.5, 1.0, 2.0 were prepared by melt quenching technique and characterized through absorption and emission spectra, CIE chromaticity coordinates and decay rate analysis. Judd-Oflet parameters have been calculated for lithium gadolinium silico borate glass and used for the derivation of radiative properties for excited luminescent levels of Dy<SUP>3+</SUP> ions. The feasibility of white light generation have been evaluated by the yellow-to-blue emission intensity ratios and CIE chromaticity coordinates as a function of Dy<SUP>3+</SUP> concentration. The non-exponential decay rates are well-fitted to Inokuti-Hirayama model for S = 6. The perceived non-exponential decay nature and life time quenching have been ascribed to the energy transfer between excited and unexcited Dy<SUP>3+</SUP> ions through dipole–dipole interaction. The CCT values for the present studied glasses obtained in the 4584-4235 K at λ<SUB>exc</SUB> = 387 nm. These CCT values are below the warm CCT (i.e CCT 4000 K). The reasonably good luminescence properties of LGSiBDy10 glass indicates the potentiality of the title of glass to be applied as lasing medium for white light generation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Spectroscopic properties of Dy<SUP>3+</SUP> ion in Li<SUB>2</SUB>OGd<SUB>2</SUB>O<SUB>3</SUB> SiO<SUB>2</SUB> B<SUB>2</SUB>O<SUB>3</SUB> were studied. </LI> <LI> JO analysis were used to analyze spectroscopic properties. </LI> <LI> White emission was observed from glass sample. </LI> <LI> Lasing properties were characterized. </LI> </UL> </P>

A comparative study of gadolinium based oxide and oxyfluoride glasses as low energy radiation shielding materials

Shamshad, L.,Rooh, G.,Limkitjaroenporn, P.,Srisittipokakun, N.,Chaiphaksa, W.,Kim, H.J.,Kaewkhao, J. Elsevier 2017 Progress in nuclear energy Vol.97 No.-

<P><B>Abstract</B></P> <P>The Gadolinium based oxide and oxyfluoride glass systems were prepared using conventional melt quenching method and studied for their radiation shielding properties. The mass attenuation coefficients (μ<SUB>m</SUB>), effective atomic numbers (Z<SUB>eff</SUB>) and effective electron densities (N<SUB>e</SUB>) of the glasses at different photon energies were calculated theoretically by WinXcom program and experimentally determined by the transmission method. Moreover, the mass attenuation coefficient was investigated using Geant4 Monte Carlo code and compared with each other. The gamma ray energies were varied by Compton scattering technique. The values of attenuation parameters of both the glass systems have been found to be decrease with the increase in gamma ray photon energy. The results show that, the experimental values of mass attenuation coefficients, effective atomic numbers and effective electron densities are in good agreement with the theoretical values. It seems that Geant4 values are systematically lower than WinXCom. It could be caused by the simplification of geometry in Geant4. Although, the oxide glass system have superior shielding properties than oxyfluoride glass system, but, still, it has better shielding properties than commercial window glass and some existing concretes indicating the potential of this glass to be used as gamma ray shielding material. Moreover, there is no effect of fluoride component on the optical spectra. The optical absorption spectra of the glass systems under investigation have been shown with light transparency which is an edge to be used as radiation shielding material.</P>

Luminescence characteristics of Sm³⁺-doped lithium barium gadolinium silicate glasses for Orange LED's

Khan, I.,Rooh, G.,Rajaramakrishna, R.,Srisittipokakun, N.,Kim, H.J.,Kirdsiri, K.,Kaewkhao, J. Elsevier 2019 Spectrochimica acta. Part A, Molecular and biomole Vol.214 No.-

<P><B>Abstract</B></P> <P>Traditional melt-quenching technique is adopted for synthesis of Sm<SUB>2</SUB>O<SUB>3</SUB> doped lithium barium gadolinium silicate (LBGS: Li<SUB>2</SUB>O-BaO-Gd<SUB>2</SUB>O<SUB>3</SUB>-SiO<SUB>2</SUB>) glasses. These glass samples are characterized by different spectroscopic techniques under ambient conditions. Density and molar volume of the present LBGS glass samples increase with increasing Sm<SUP>3+</SUP> ion-concentration. JO intensity parameters Ω<SUB>λ</SUB> (where λ = 2, 4 and 6) are evaluated by using Judd-Ofelt theory and Ω<SUB>4</SUB> > Ω<SUB>2</SUB> > Ω<SUB>6</SUB> trend is observed. Furthermore, these parameters are used to evaluate radiative properties like radiative transition probability, branching ratio, radiative lifetime and stimulated emission cross-section for state <SUP>4</SUP>G<SUB>5/2</SUB> of Sm<SUP>3+</SUP> ion. The measured color coordinates for the title glass fall within orange region of CIE diagram. For the present LBGS glasses, the correlated color temperature values are less than warm. The lifetime for the <SUP>4</SUP>G<SUB>5/2</SUB> decreases from 2.468 to 0.566 ms when concentration increases from 0.1 to 2.0 mol% of Sm<SUP>3+</SUP> ions. The analysis of non-exponential behavior of the decay profile through Inokuti-Hirayama model for S = 6 indicates that the energy transfer between Sm<SUP>3+</SUP> ions is due to dipole-dipole interactions. Further energy transfer parameters (Q), critical distance (R<SUB>o</SUB>, Å) and donor-acceptor interaction parameters (C<SUB>DA</SUB> x 10<SUP>−40</SUP> cm<SUP>6</SUP>/s) of Sm<SUP>3+</SUP> ions doped LBGS glasses were evaluated and compared to other glasses. From the evaluated results it is suggested that the present novelty of the work emphasizes on new matrix LBGS doped with Sm<SUP>3+</SUP> ions showing increasing energy transfer rate with increasing in concentration of Sm<SUB>2</SUB>O<SUB>3</SUB> content indicating these glasses are potential candidate for orange-light emitting device applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel matrix Li<SUB>2</SUB>O- BaO- Gd<SUB>2</SUB>O<SUB>3</SUB>-SiO<SUB>2</SUB>-Sm<SUB>2</SUB>O<SUB>3</SUB> were synthesized by melt quenching method. </LI> <LI> J-O (Ω<SUB>λ</SUB>) parameters for 0.5Sm<SUP>3+</SUP> doped sample were analyzed. </LI> <LI> Lifetime of <SUP>4</SUP>G<SUB>5/2</SUB> decreases from 2.468 to 0.566 ms with increase in concentration. </LI> <LI> LBGS sample emit bright reddish-orange luminescence under 402 nm excitation. </LI> <LI> Opening of cross-relaxation channels has observed due increase in energy transfer parameters with increase in Sm<SUP>3+</SUP> ions. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>