Investigations of optical and luminescence features of Sm³⁺ doped Li₂O-MO-B₂O₃ (M =Mg/Ca/Sr/Ba) glasses mixed with different modifier oxides as an orange light emitting phosphor for WLED's

Kirdsiri, K.,Raja Ramakrishna, R.,Damdee, B.,Kim, H.J.,Kaewjaeng, S.,Kothan, S.,Kaewkhao, J. Elsevier 2018 JOURNAL OF ALLOYS AND COMPOUNDS Vol.749 No.-

<P><B>Abstract</B></P> <P>The glass composition of 50Li<SUB>2</SUB>O-20MO-29.7B<SUB>2</SUB>O<SUB>3</SUB>-0.3Sm<SUB>2</SUB>O<SUB>3</SUB> (M = Mg/Ca/Sr/Ba), has been synthesized by the conventional melt quench technique. Density measurements were studied and shows large for LBaBSm glass sample (2.9049 g/cm<SUP>3</SUP>) than any other alkali species (Mg/Ca/Sr). Variation in density is due to the ionic radii of the alkali ion species (M = Mg/Ca/Sr/Ba). Optical absorption spectra of Sm<SUP>3+</SUP> doped LMgB, LCaB, LSrB and LBaB glass systems were studied and shows very intense peaks at NIR region. The emission and excitation spectra of these glasses were studied and emission spectra shows green, yellow and reddish - orange emission bands at 563, 600, 646 and 706 nm. Judd–Ofelt (JO) intensity analysis had been performed and JO parameters were estimated for 0.3 mol.% Sm<SUB>2</SUB>O<SUB>3</SUB> doped 50Li<SUB>2</SUB>O-20MO-29.7B<SUB>2</SUB>O<SUB>3</SUB> (M = Mg/Ca/Sr/Ba) glasses. Radiative properties such as transition probabilities, stimulated emission cross-sections and branching ratios were estimated by using JO parameters and luminescence spectra. The decay curves of these glasses exhibit single exponential nature. The CCT values obtained from CIE for these glass samples shows 1663 K for indicating orange emission under 403 nm excitation wavelength.</P> <P><B>Highlights</B></P> <P> <UL> <LI> J-O parameters of Li2O-MO-B2O3 (M = Mg/Ca/Sr/Ba) glass doped Sm<SUP>3+</SUP> studied. </LI> <LI> LBaBSm0.3 glass show more asymmetry around Sm<SUP>3+</SUP> ion than other transition ions. </LI> <LI> LBaBSm0.3 glass emit bright reddish-orange luminescence at 403 nm excitation. </LI> <LI> The CCT values obtained for glass samples around 1663 K in orange emission. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>UV–Vis–NIR spectra of LMOBSm0.3 (M = Mg, Ca, Sr, Ba) samples.</P> <P>[DISPLAY OMISSION]</P>

Scintillation and Luminescence Properties of Sm3+-Activated Lu2O3-CaO-SiO2-B2O3 (LuCSB) Scintillating Glasses

K. Kirdsiri,J. Kaewkhao,박정민,하대훈 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.6

Lutetium (Lu) is a high atomic number material and readily interacts with X-rays, which makes it a good scintillation material. In this work, Lu-glass scintillators from the series xSm2O3 : 25Lu2 O3 : 10SiO2 : 10CaO : (55-x)B2O3 (LuCSB) were synthesized at 1500 ◦ C by using a simple melt quenching technique. The influence of the Sm3+ ion on their physical, optical, photo-, X-rayand proton-induced properties has been characterized. The amorphous nature of the samples was confirmed by using X-ray diffraction. The density and the molar volume were found to be increased at higher concentrations of Sm3+. The X-ray- and the proton-induced emission spectra of the Sm3+:LuCSB glasses showed an intense reddish-orange emission around 604 nm (4G5/2 → 6H7/2), which matched the photoluminescence (PL) emission spectrum well. Among the prepared glasses, the 1.0-mol% Sm3+ ion-activated LuCSB glass exhibited the highest value of the characteristic emission parameters. The X-ray-induced luminescence of the LuCSB glass was also compared with that of a commercial bismuth germinate Bi4Ge3O12 (BGO) crystal.

Interaction of 662 keV Gamma-rays with Bismuth-based Glass Matrices

Kaewkhao, J.,Kirdsiri, K.,Limkitjaroenporn, P.,Limsuwan, P.,Park, Jeongmin,Kim, H. J. Korean Physical Society 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.2

Interaction of 662 keV Gamma-rays with Bismuth-based Glass Matrices

J. Kaewkhao,K. Kirdsiri,P. Limkitjaroenporn,P. Limsuwan,박정민,김홍주 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.22

In this work, the Bi_2O_3-SiO_2 glass system was synthesized by using the melt-quenching method. The radiation shielding properties of the glass samples at various levels of bismuth content were measured at 662 keV by usage a ^(137)Cs radioactive source, and comparisons were made with values theoretically calculated by usage WinXCom. The experimentally obtained values were generally in good agreement with the theoretical ones. Furthermore, a comparison was made to a lead-borate glass system with the same level of additive. The radiation shielding properties were found to be improved with increasing Bi_2O_3 concentration. The different values of Compton scattering yielded a higher total mass attenuation coefficient for the bismuth-silicate glass than for the bismuth-borate glass. These results reflect the potential usefulness of bismuth-based glasses as new materials for lead-free radiation-shielding glasses.

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>

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.

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>

Energy transfer phenomenon of Gd³⁺ to excited ground state of Eu³⁺ ions in Li₂O-BaO-Gd₂O₃-SiO₂-Eu₂O₃ glasses

Khan, I.,Rooh, G.,Rajaramakrishna, R.,Sirsittapokakun, N.,Kim, H.J.,Kaewkhao, J.,Kirdsiri, K. Elsevier 2019 Spectrochimica acta. Part A, Molecular and biomole Vol.210 No.-

<P><B>Abstract</B></P> <P>Li<SUB>2</SUB>O-BaO-Gd<SUB>2</SUB>O<SUB>3</SUB>-SiO<SUB>2</SUB> glasses with different concentration of Eu<SUP>3+</SUP> ions were developed by the traditional melt quenching technique and characterized via FTIR, absorption, excitation, emission and CIE color coordinates analysis for visible red emission application. The FTIR shows strong band at position 740 cm<SUP>−1</SUP> which is attributed to Si-O-Si symmetric stretching mode. Density and molar volume of LBGSEu glasses increases with Eu<SUP>3+</SUP> ions concentration. The covalent nature of bond between the Eu<SUP>3+</SUP> ions and surrounding ligands was confirmed from the bonding parameter (δ). From absorption spectra JO-parameters and oscillator strength are evaluated for LBGSEu6 glass. From JO-parameters, Eu<SUP>3+</SUP> ions have asymmetric coordination environment and stronger covalency. The phonon line PSB (22,522 cm<SUP>−1</SUP>) confirm the phonon energy ≈971 cm<SUP>−1</SUP>, that corresponds to the energy of one phonon associated with maximum energy of the vibrational mode couple to Eu<SUP>3+</SUP> ions. Under 275 nm and 393 nm excitation, intense red emission was observed at 613 nm, we observe efficient energy transfer phenomena from Gd<SUP>3+</SUP> → Eu<SUP>3+</SUP> in these glasses. Increasing trend of I<SUB>R</SUB> with increasing concentration of Eu<SUB>2</SUB>O<SUB>3</SUB> indicates the asymmetric environment around Eu<SUP>3+</SUP> ions in LBGS. Moreover, from JO analysis, LBGS glasses have high capability for red laser device with high lasing power and energy extraction ratio. The fluorescence lifetimes show decreasing trend in lifetime with increasing concentration of Eu<SUB>2</SUB>O<SUB>3</SUB> is due to radiative transition. From CIE color coordinate, the CIE color coordinates of LBGSEu6 glass fall in reddish region close to orange region and can be useful for optical display devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Li<SUB>2</SUB>O-BaO-Gd<SUB>2</SUB>O<SUB>3</SUB>-SiO<SUB>2</SUB> glasses were prepared by melt quenching method. </LI> <LI> Energy transfer phenomena from Gd<SUP>3+</SUP> → Eu<SUP>3+</SUP> were found in these glasses. </LI> <LI> Luminescence intensity found to be more intense at 613 nm red emission. </LI> <LI> The one phonon line PSB (22,522 cm<SUP>−1</SUP>) confirm the phonon energy ≈971 cm<SUP>−1</SUP>. </LI> <LI> The fluorescence lifetimes show decreasing trend with increasing content of Eu<SUB>2</SUB>O<SUB>3</SUB>. </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>LBGSEu emission (λ<SUB>ext</SUB> = 275 nm) region (560 nm–720 nm).</P> <P>[DISPLAY OMISSION]</P>