White light emission of dysprosium doped lanthanum calcium phosphate oxide and oxyfluoride glasses

Luewarasirikul, N.,Kim, H.J.,Meejitpaisan, P.,Kaewkhao, J. Elsevier 2017 Optical materials Vol.66 No.-

<P><B>Abstract</B></P> <P>Lanthanum calcium phosphate oxide and oxyfluoride glasses doped with dysprosium oxide were prepared by melt-quenching technique with chemical composition 20La<SUB>2</SUB>O<SUB>3</SUB>:10CaO:69P<SUB>2</SUB>O<SUB>5</SUB>:1Dy<SUB>2</SUB>O<SUB>3</SUB> and 20La<SUB>2</SUB>O<SUB>3</SUB>:10CaF<SUB>2</SUB>:69P<SUB>2</SUB>O<SUB>5</SUB>:1Dy<SUB>2</SUB>O<SUB>3</SUB>. The physical, optical and luminescence properties of the glass samples were studied to evaluate their potential to using as luminescence materials for solid-state lighting applications. The density, molar volume and refractive index of the glass samples were carried out. The optical and luminescence properties were studied by investigating absorption, excitation, and emission spectra of the glass samples. The absorption spectra were investigated in the UV–Vis–NIR region from 300 to 2000 nm. The excitation spectra observed under 574 nm emission wavelength showed the highest peak centered at 349 nm (<SUP>6</SUP>H<SUB>15/2</SUB> → <SUP>6</SUP>P<SUB>7/2</SUB>). The emission spectra, excited with 349 nm excitation wavelength showed two major peaks corresponding to 482 nm blue emission (<SUP>4</SUP>F<SUB>9/2</SUB> → <SUP>6</SUP>H<SUB>15/2</SUB>) and 574 nm yellow emission (<SUP>4</SUP>F<SUB>9/2</SUB> → <SUP>6</SUP>H<SUB>13/2</SUB>). The experimental lifetime were found to be 0.539 and 0.540 for oxide and oxyfluoride glass sample, respectively. The x,y color coordinates under 349 nm excitation wavelength were (0.38, 0.43) for both glass samples, that be plotted in white region of CIE 1931 chromaticity diagram. The CCT values obtained from the glass samples are 4204 K for oxide glass and 4228 K for oxyfluoride glass corresponding to the commercial cool white light (3100–4500 K). Judd-Ofelt theory had also been employed to obtain the J-O parameters (Ω<SUB>2</SUB>, Ω<SUB>4</SUB> and Ω<SUB>6</SUB>), oscillator strength, radiative transition possibility, stimulated emission cross section and branching ratio. The Ω<SUB>2</SUB> > Ω<SUB>4</SUB> > Ω<SUB>6</SUB> trend of J-O parameters of both glass samples may indicate the good quality of a glass host for using as optical device application. Temperature dependence of emission spectra was studied from 300 K to 10 K and found that the intensity of the emission peak was found to be increased with decreasing of the temperature. The results of the investigations in this work confirmed that the present Dy-doped lanthanum calcium phosphate oxide and oxyfluoride glasses perform high potential for using as efficient luminescence materials for solid-state lighting applications, especially for white LEDs. Furthermore, the oxyfluoride glass sample provides more luminescence potential than the oxide glass sample.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Lanthanum calcium phosphate oxide and oxyfluoride glasses doped with Dy<SUP>3+</SUP> were studied. </LI> <LI> Emission spectra showed two major peaks corresponding to 482 and 574 nm. </LI> <LI> Both glasses corresponding to the commercial cool white light (3100–4500 K). </LI> <LI> Judd-Ofelt theory had also been employed to obtain the J-O parameters. </LI> <LI> Oxyfluoride glass provides more luminescence potential than the oxide glass. </LI> </UL> </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>

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>

Optical Properties in the Visible Luminescence of SiO2:B2O3:CaO:GdF3 Glass Scintillators Containing CeF3

J. M. PARK,김홍주,Sujita Karki,J. Kaewkhao,B. Damdee,S. Kothandaraman,S. Kaewjaeng 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.71 No.11

CeF3-doped silicaborate-calcium-gadolinium glass scintillators, with the formula 10SiO2:(55- x)B2O3:10CaO:25GdF3:xCeF3, were fabricated by the melt-quenching technique. The doping concentration of the CeF3 was from 0.00 mol% to 0.20 mol%. The optical properties of the CeF3 doped glass scintillators were studied by using various radiation sources. The transition state of the CeF3- doped glass scintillators studied by using the absorption and photo-luminescence spectrum results. The X-ray, photo, proton and laser-induced luminescence spectra were also studied to understand the luminescence mechanism under various conditions. To understand the temperature dependence, the laser-induced luminescence and the decay component of the CeF3-doped glass scintillator were studied while the temperature was varied from 300 K to 10 K. The emission wavelength spectrum showed from 350 nm to 55 nm under various radiation sources. Also the CeF3-doped glass scintillator have one decay component as 34 ns at room temperature.

Luminescence Property of Rare-earth-doped Bismuth-borate Glasses with Different Concentrations of Bismuth and Rare-earth Material

J. M. Park,P. Limsuwan,J. Kaewkhao,김홍주,김성환 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.2

Bismuth-borate glass scintillators have high density and good radiation hardness. Thus, if they are highly luminescent, they can be applied in astrophysics, high-energy and nuclear physics, homeland security, radiation detection and medical imaging. Bismuth-borate glasseswith the formula xBi₂O₃:(100 − x)B₂O₃ (x = 30, 50, and 66.7 mol%) were fabricated and doped with Nd, Er, Dy, Pr, Sm, Ho, Gd, and Ce in different dopant concentrations by using the melt-quenching technique. The X-ray emission spectra for the bismuth-borate glasses were measured and showed that only Sm-, Dy-, and Nd-doped glass scintillators had noticeable luminescence. Also, we measured the photo-luminescence and the proton-induced emission spectra. We obtained the result that Sm- and Dy- doped glass scintillators emitted luminescence. The emission peaks of the Sm- doped glass were 569, 598, 641, and 708 nm and were due to (⁴G_5/2 → ⁶H_<i>J</i> ) (<i>J</i> = 5/2, 7/2, 9/2, 11/2) transitions, respectively. The emission peaks of the Dy- doped glass were at 485 nm (⁴F_9/2 → ⁶H_15/2), 575 nm (⁴F_9/2 → ⁶H_13/2), 660 nm (⁴F_9/2 → ⁶H_11/2), and 755 nm (⁴F_9/2 → ⁶H_9/2 + ⁶H_11/2), and that of the Nd-doped glass was at 895 nm due to the (⁴F_3/2 → ⁴I_9/2) transition. The luminescence intensities were compared in terms of different Bi concentrations and dopant concentrations.

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

Luminescence characteristics of Dy3+ doped Gd2O3-CaO-SiO2-B2O3 scintillating glasses

Kaewkhao, J.,Wantana, N.,Kaewjaeng, S.,Kothan, S.,Kim, H.J. Elsevier 2016 Journal of rare earths Vol.34 No.6

<P>Glasses were prepared from the compositions of 25Gd(2)O(3)-10CaO-10SiO(2)-(55-x)B2O3-xDy(2)O(3) (where x is 0.0 mol.%-1.0 mol.%) by the conventional melt-quenching technique at 1400 degrees C. The results demonstrated the increase in the glass density with respect to the increase in the doping concentrations of Dy2O3. Nine absorption bands were observed. The emission spectra of the developed glass showed two strong peaks at 577 nm (F-4(9/2)-> H-6(13/2)) and 482 nm (F-4(9/2)-> 6H(15/2)). The highest emission intensity was observed from the developed glass prepared at 0.4 mol.% of Dy2O3, as the efficient energy transfer took place from Gd3+ to Dy3+. From the X-ray induced optical luminescence, the emission spectra were identical to those from PL measurements, but with the highest intensity observed from the glass quenched at 0.45 mol.% of Dy2O3. Finally, the integral scintillation efficiency of the developed glass was determined at 27% of that of the commercially available BGO crystal.</P>

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.

Optical properties in the visible luminescence of SiO2:B2O3:CaO:GdF3 glass scintillators containing CeF3

Park, J. M.,Kim, H. J.,Karki, Sujita,Kaewkhao, J.,Damdee, B.,Kothan, S.,Kaewjaeng, S. 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol. No.

<P>CeF3-doped silicaborate-calcium-gadolinium glass scintillators, with the formula 10SiO(2):(55-x)B2O3:10CaO:25GdF(3):xCeF(3), were fabricated by the melt-quenching technique. The doping concentration of the CeF3 was from 0.00 mol% to 0.20 mol%. The optical properties of the CeF3 doped glass scintillators were studied by using various radiation sources. The transition state of the CeF3-doped glass scintillators studied by using the absorption and photo-luminescence spectrum results. The X-ray, photo, proton and laser-induced luminescence spectra were also studied to understand the luminescence mechanism under various conditions. To understand the temperature dependence, the laser-induced luminescence and the decay component of the CeF3-doped glass scintillator were studied while the temperature was varied from 300 K to 10 K. The emission wavelength spectrum showed from 350 nm to 55 nm under various radiation sources. Also the CeF3-doped glass scintillator have one decay component as 34 ns at room temperature.</P>

Scintillation Properties of Ce3+ Doped Silicon-Magnesium-Aluminum-Lithium Glass Scintillators by using Radiation Sources

S. C. Kang,H. J. Kim,J. Y. Choi,G. S. Kim,Pabitra Aryal,Arshad Khan,S. J. Kang,J. Kaewkhao,J. M. PARK,MinJeong Kim 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.8

Glass scintillators can be doped with different elements to improve their luminescence properties. In this study, we present 0.5 wt% Ce3+-doped (58x)SiO2-4MgO-18Al2O3-20Li2O and (58x)SiO2- 4MgO-18Al2O3-20LiF glass scintillators. We used a pulsed laser to measure the laser-induced emission spectrum and the decay time with decreasing temperature from 300 K to 10 K. The light intensity of both glass samples increased with decreasing temperature from 300 K to 10 K. Additionally, the two glass samples exhibited a fast decay time of approximately 25 ns. In the photo-induced spectrum, an excitation peak at 312 nm and two emission peaks, at 370 nm and 700 nm, were observed in both the glass samples. The X-ray-induced emission intensity of former is approximately six times higher than that of latter, and only former glass sample exhibits a proton-induced emission spectrum.