Concentration dependent Eu³⁺ doped boro-tellurite glasses鈥擲tructural and optical investigations

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• 作者：K. Maheshvaran ; K. Marimuthu ; ^{mari_ram2000@yahoo.com}
• 关键词：Absorption ; Photoluminescence ; Judd&ndash ; Ofelt analysis ; Band tailing parameter ; Urbach energy
• 刊名：Journal of Luminescence
• 出版年：2012
• 期刊代码：54_00222313
• 类别：ch
• 出版时间：September, 2012
• 卷：132
• 期：9
• 页码：2259-2267
• 文件大小：462 K

摘要

Eu³⁺ doped boro-tellurite glasses with the chemical composition (40鈭?em>x)B₂O₃+30TeO₂+15MgO+15K₂O+xEu₂O₃ (where x=0.01, 0.1, 1, 2 and 3 wt%) have been prepared by following the conventional melt quenching technique. Structural and optical behavior of the prepared Eu³⁺ doped boro-tellurite glasses were studied and compared with reported literature. The XRD pattern confirms the amorphous nature and the FTIR spectral studies explore the presence of B顥窸 stretching vibrations, O₃B顥窸顥窧O₃ bond bending vibrations along with the bending vibration of Te顥窸顥窽e linkages in the prepared glasses. Through the optical absorption spectra, bonding parameters () were calculated to identify the ionic/covalent nature of the glasses. Judd-Ofelt (JO) parameters have been calculated from the luminescence spectral measurements. The JO parameters (惟_位, 位=2, 4 and 6) were used to calculate the radiative properties like transition probability (A), stimulated emission cross-section (), radiative lifetime (蟿_rad), and branching ratios (尾_R) for the ⁵D₀鈫?sup>7F_J (J=0, 1, 2, 3 and 4) emission transitions of the Eu³⁺ ions. The local site symmetry around the Eu³⁺ ions were calculated through the luminescence intensity ratio (R) of the ⁵D₀鈫?sup>7F₂ to ⁵D₀鈫?sup>7F₁ transitions. The experimental lifetime of the ⁵D₀ level in the Eu³⁺ doped boro-tellurite glasses has also been calculated and compared with similar Eu³⁺ glasses. The lifetime of the ⁵D₀ level is found to be less than the reported glasses and it may be due to the presence of OH^{鈭?/sup> groups in the prepared glasses. The Optical band gap (E_opt), band tailing parameter (B) and the Urbach energy (螖E) values of the prepared glasses were calculated from the absorption spectral measurements and the results were discussed and reported.}