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Energy transfer phenomenon of Gd3+ to excited ground state of Eu3+ ions in Li2O-BaO-Gd2O3-SiO2-Eu2O3 glasses
摘要： Li2O-BaO-Gd2O3-SiO2 glasses with different concentration of Eu3+ 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-1 which is attributed to Si-O-Si symmetric stretching mode. Density and molar volume of LBGSEu glasses increases with Eu3+ ions concentration. The covalent nature of bond between the Eu3+ 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, Eu3+ ions have asymmetric coordination environment and stronger covalency. The phonon line PSB (22522 cm-1) confirm the phonon energy ≈ 971 cm-1, that corresponds to the energy of one phonon associated with maximum energy of the vibrational mode couple to Eu3+ ions. Under 275 nm and 393 nm excitation, intense red emission was observed at 613 nm, we observe efficient energy transfer phenomena from Gd3+ → Eu3+ in these glasses. Increasing trend of IR with increasing concentration of Eu2O3 indicates the asymmetric environment around Eu3+ 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 Eu2O3 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.
关键词： Judd-Ofelt analysis,Silicate glasses,Energy transfer,emission cross sections,Rare earth
更新于2025-09-23 15:21:01
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Energy Transfer and Spectroscopic Investigation of Dy2O3 Doped Li2O–BaO–GdF3–SiO2 for White Light LED
摘要： LGFDy glasses doped with Dy2O3 (0.1, 0.5, 1.0, 1.5 and 2.0 mol %) were synthesised by conventional melt quenching method and various properties are studied by absorption, Judd–Ofelt analysis, photoluminescence, X-ray excited luminescence, decay curve and CIE color chromaticity measurement. Judd-Ofelt parameters (?2, ?4 and ?6) are valuated form JO theory in order to estimate the radiative parameters of the Dy3+ ion excited states. For white light emission, Yellow/Blue (Y/B) ratio and CIE color coordinates for glasses under study are measured from the emission spectra. The energy transfer from Gd3+ to Dy3+ ions has been studied by exciting the glass with 275 nm photon. The higher value of σ (λp) and βR for 4F9/2 → 6H13/2 transition indicates its more potential use in laser application in yellow region. The correlated color temperature for LGFDy glasses is found to be 4264 K. The decay profile of fluorescent level 4F9/2 for different concentration of Dy3+ ions in the present glasses changes to non-exponential from single-exponential for higher concentration (≥0.5 mol %) of Dy3+ ions. Thus the chemical composition of glass and dopant (Dy3+ ions) concentration strongly influence the energy transfer mechanism. The lifetime non-exponential behavior is well fitted to IH-model for S = 6. The quantum efficiency for LBGFDy05 glass is found to be 86%. The systematic investigation signifies the potential of the studied LGFDy glasses for the laser and white light generation application.
关键词： silicate glasses,dysprosium,decay time,energy transfer,resonance energy transfer
更新于2025-09-19 17:13:59
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Luminescence of Cr3+/Yb3+ co-doped oxyfluoride silicate glasses for crystalline silicon solar cell down-conversion devices
摘要： Oxy?uoride silicate glasses co-doped with Cr3+ and Yb3+ ions were fabricated in this work. High △T (178–214 °C) value demonstrated that the thermal stability of the prepared glasses were better than tellurite and germanate glasses. X-ray di?raction (XRD) curves proved the amorphous nature of the glasses, the energy dispersive spectroscopy (EDS) analysis and Fourier Transform infrared spectroscopy (FT-IR) curves explored the network structure of glasses. The photoluminescence excitation (PLE) and photoluminescence emission (PL) spectra show that the glasses absorption peaks located at 430 nm (Cr3+:4A2g - 4T1g (P)) and 627 nm (Cr3+:4A2g - 4T2g), while the emission peak close to 1010 nm (Yb3+:2F5/2 -2F7/2), which meets the condition of energy down-conversion. Besides, the energy transfer e?ciency (ηCET = 33.5%) and the quantum cutting e?ciency (ηQE = 133.5%) were calculated from the measured decay curves. These values were higher than Cr3+/Yb3+ co-doped ?uorosilicate glass with incorporating of CaF2 (21.5% and 123.5%) and Tb3+/Yb3+ oxy?uoride glass (13.5% and 113.5%), indicating the prepared samples are conducive to the energy transfer from Cr3+ to Yb3+ ions. The experimental results reveal that the oxy?uoride silicate glasses have potential application prospects in crystalline silicon (c-Si) solar cells.
关键词： Oxy?uoride silicate glasses,Melt-quenching method,Down-conversion and near-infrared luminescence emission,Crystalline silicon (c-Si) solar cells
更新于2025-09-19 17:13:59