Bohdan V. Padlyak; Ihor I. Kindrat; Radoslaw Lisiecki; Volodymyr T. Adamiv; Ihor M. Teslyuk
Volume 8, Issue 6 , June 2017, , Pages 723-734
Abstract
The spectroscopic and radiative properties of the Sm-doped borate glasses with Li2B4O7, LiKB4O7, CaB4O7, and LiCaBO3 basic compositions as new luminescent materials have been investigated and analysed. The borate glasses of high chemical purity and optical quality, doped with Sm2O3 in amounts of 0.5 ...
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The spectroscopic and radiative properties of the Sm-doped borate glasses with Li2B4O7, LiKB4O7, CaB4O7, and LiCaBO3 basic compositions as new luminescent materials have been investigated and analysed. The borate glasses of high chemical purity and optical quality, doped with Sm2O3 in amounts of 0.5 and 1.0 mol. % were obtained from corresponding polycrystalline compounds in the air atmosphere using standard glass synthesis technology. The spectroscopic properties of obtained Sm-doped glasses were studied using electron paramagnetic resonance (EPR), optical absorption, photoluminescence, and decay kinetics techniques. The Judd–Ofelt theory had been used for analysis of the optical absorption spectra and calculation of the phenomenological intensity parameters (Ω2, Ω4, Ω6). Radiative properties such as transition probabilities (Arad), branching ratios (βexp < /sub> and βrad), stimulated emission cross-sections (σe), and radiative lifetimes (τrad) were estimated for 4 G5/2 → 6 HJ (J = 5/2, 7/2, 9/2, and 11/2) emission transitions of the Sm 3+ ions in the Li2B4O7:Sm, CaB4O7:Sm, and LiCaBO3:Sm glasses containing 1.0 mol. % Sm2O3. The luminescence kinetics of Sm 3+ centres in the investigated glasses are characterised by a single exponent decay with typical lifetimes, which depend on the basic glass composition and Sm impurity concentration. Experimental lifetimes (τexp < /sub>) have been compared with those calculated (τrad) and quantum efficiencies (η) of the Sm 3+ emission transitions were estimated. The calculated high quantum efficiencies (~ 80 %) and measured high quantum yields of luminescence (~ 14 – 21 %) clearly show that the investigated glasses belong to very promising materials for luminescent and laser applications.
Thoudam Nando Singhi; Thongam Gomti Devi; Shougaijam Dorendrajit Singh
Volume 8, Issue 4 , April 2017, , Pages 557-564
Abstract
Eu 3+ doped TiO2 (0.2-1at. %) is synthesized successfully by non-aqueous sol-gel technique at low temperature. They are characterized structurally and optically with the used of X-ray diffraction (XRD), UV-visible spectrophotometer, Photoluminescence (PL), microscopy (SEM) and Transmission electron microscopy ...
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Eu 3+ doped TiO2 (0.2-1at. %) is synthesized successfully by non-aqueous sol-gel technique at low temperature. They are characterized structurally and optically with the used of X-ray diffraction (XRD), UV-visible spectrophotometer, Photoluminescence (PL), microscopy (SEM) and Transmission electron microscopy (TEM). The anatine toretile phase transition is observed at 750 o C and lattice distortion ratios are reduced whereas crystallites sizes are found to increase with increases of temperature. The emission spectrum under excitation at the 7 F0→ 5 L6 (393nm) transition of the Eu 3+ ion shows broad emission bands arising from the 5 DJ (J=0, 1) levels and with the emission decays lifetime varying between 0.243 and 0.375ms for samples prepared at different temperatures. The Judd-Ofelt intensity parameters W2 are found in the range 6.57 - 17.14 x10 -20 cm 2 at different concentrations and temperatures. Quantum yield of all the samples are more than 80% at different temperature. The average decay lifetime decreases with the increase of Eu 3+ concentration.
