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Stambouli W.,Center National Of Recherches En Science Des Materiaux | Elhouichet H.,Center National Of Recherches En Science Des Materiaux | Elhouichet H.,University of Tunis | Gelloz B.,Nagoya University | Ferid M.,Center National Of Recherches En Science Des Materiaux
Journal of Luminescence | Year: 2013

Tellurite glasses doped with trivalent europium were prepared by the conventional melt quenching technique, in the chemical composition of (85-x) TeO2+5La2O3+10TiO2+xEu 2O3 by varying the concentration of the rare-earth ion in the order 0.5, 1 and 1.5 mol%. Using Judd-Ofelt analysis, we calculated intensity parameters (Ω2 and Ω4), spontaneous emission probabilities, the radiative lifetime, luminescence branching factors, the quantum yield of luminescence, and the stimulated emission cross-sections for 5D0→7F2 transition. The change in optical properties with the variation of Eu3+ ion concentration have been discussed and compared with other glasses. The luminescence intensity ratio, quantum efficiency and emission cross-section values support that the TeEu1.5 tellurite glass is a suitable candidate for red laser source applications. Optical properties for Eu3+ doped tellurite glass, heated for different temperature, were investigated. Crystalline phases for α-TeO2, γ-TeO2 and TiTe3O8 system were determined by the XRD method. The effect of heat treatment on luminescence properties in the tellurite glass was discussed. By using Eu3+ as a probe, the local structure of rare-earth ion in tellurite glass, vitro-ceramic and ceramic glass has been investigated. The evaluated J-O intensity parameters have been used to calculate different radiative and laser characteristic parameters of the 5D0 excited level. The large magnitudes of stimulated emission cross-section (σe), branching ratio (β) and Gain bandwidth (σe×Δλeff) obtained for 5D0→7F2 (613 nm) transition for ceramic glass indicate that the present glass ceramic is promising host material for Eu3+doped fiber amplifiers. The measured lifetime of 5D0 excited state increases with increase of the heat treatment which further indicate that some Eu3+ ions were successfully embedded in the crystal phase and prove the low phonon energy environment of Eu3+ ions in the nanocrystals precipitated in the glass ceramics. © 2013 Elsevier B.V.


Stambouli W.,Center National Of Recherches En Science Des Materiaux | Elhouichet H.,Center National Of Recherches En Science Des Materiaux | Elhouichet H.,University of Tunis | Barthou C.,University Pierre and Marie Curie | Ferid M.,Center National Of Recherches En Science Des Materiaux
Journal of Alloys and Compounds | Year: 2013

Tellurite glasses doped with Er3+, Er3+/Ce 3+ and Er3+/Ce3+/Yb3+, have been elaborated from the conventional melt-quenching method. It was found that both the photoluminescence (PL) intensity and the PL lifetime relative to the 4I13/2→4I15/2 transition of Er3+ were found to increase with Ce3+ co-doping and Yb3+ tri-doping. We show that an efficient energy transfer can occur from Ce3+ and Yb3+ to Er3+. Efficient green (533 nm, 546 nm) emission spectra, associated to the 2H 11/2→4I15/2, and 4S 3/2→4I15/2 transitions of Er3+ respectively, were observed. By adding Ce3+ ions, the intensities of green up-conversion emissions were found to decrease hardly do to energy transfer rate of Er3+:4I11/2→ Ce 3+:2F5/2. Band diagram energy is proposed to explain the up-converted PL, under 980 nm excitation, in mono-doped, codoped and tri-doped glasses. The results suggest that Er3+/Yb 3+/Ce3+ tri-doped tellurite glass may be a potential material for developing optical amplifiers and up-conversion optical devices. © 2013 Elsevier B.V. All rights reserved.


Sdiri N.,University of Monastir | Elhouichet H.,Center National Of Recherches En Science Des Materiaux | Azeza B.,University of Monastir | Mokhtar F.,Center National Of Recherches En Science Des Materiaux
Journal of Non-Crystalline Solids | Year: 2013

Glass systems of composition (90-x) P2O5 + xB 2O3 + 10Fe2O3 (x = 0 mol.%, 10 mol.%, 20 mol.%, 30 mol.%, 40 mol.%) were prepared using normal melt-quench technique. The Mossbauer Effect has been used intensively to help investigate the structure and bonding of oxide glasses. The Mössbauer spectra indicate the presence of iron (II) and iron (III) in tetrahedral or octahedral coordination. The dependence of electrical data was analyzed in the frame work of the impedance Cole-Cole plot in a frequency range from 5 Hz to 19.5 MHz at room temperature. Constant-phase elements (CPE) are used in equivalent electrical circuits for the fitting of experimental impedance data. The frequency dependence of the electric conductivity was found to follow a simple power law behavior, in accordance with the relation σ(f) = σ(0) + Af s, where s is smaller than 1. The thermal activation energies for the electronic conduction were estimated on the basis of the Arrhenius plots. © 2013 Elsevier B.V.


Tabib A.,Center National Of Recherches En Science Des Materiaux | Sdiri N.,Center National Of Recherches En Science Des Materiaux | Elhouichet H.,Center National Of Recherches En Science Des Materiaux | Elhouichet H.,Tunis el Manar University | Ferid M.,Center National Of Recherches En Science Des Materiaux
Journal of Alloys and Compounds | Year: 2015

Na doped ZnO nanoparticles (NPs) were elaborated by sol gel technique. The X-ray diffraction patterns show that the peaks are indexed to the hexagonal structure without any trace of an extra phase. Electric and dielectric properties were investigated using complex impedance spectroscopy. The impedance spectra were analyzed in terms of equivalent circuits involving resistors, capacitors and constant phase elements (CPE). The contribution of grain boundary resistance to the total resistance of the system is remarkable. The AC conductivity increases with temperature following the Arrhenius law, with single apparent activation energy for conduction process. The frequency dependence of the electric conductivity follows a simple power law behavior, in according to relation σAC(ω) = σ(0) + A ωs, where s is smaller than 1. The analysis of dc conductivity indicates that the conduction is ionic in nature. The study of its variation, at fixed temperature, with Na content shows sharp decrease which is explained by the formation of NaZn acceptor. It was found that the dc conductivity reaches its minimum value for critical Na concentration of 1.5% at which the conductivity is estimated to be of p-type. Impedance and modulus study reveals the temperature dependent non-Debye type relaxation phenomenon. Dielectric studies revealed a promising dielectric properties (relatively high ε′ at low frequencies and low loss at high frequencies). In the low-frequency region, the values of M′ tends to zero suggesting negligible or absent electrode polarization phenomenon. The frequency dependent maxima in the imaginary modulus are found to obey to Arrhenius law. © 2014 Elsevier B.V. All rights reserved.


Sdiri N.,Center National Of Recherches En Science Des Materiaux | Elhouichet H.,Center National Of Recherches En Science Des Materiaux | Barthou C.,CNRS Nanosciences Institute of Paris | Ferid M.,Center National Of Recherches En Science Des Materiaux
Journal of Molecular Structure | Year: 2012

In this work, Judd-Ofelt analysis is applied to an extensive series of Er 3+-doped and Er 3+, Yb 3+-codoped in phosphate-borate glass in order to evaluate their potential as both glass laser systems and amplifier materials. A spectroscopic investigation is presented. The phenomenological Judd-Ofelt parameters Ω 2, Ω 4 and Ω 6 are determined for both rare-earth ions together with their quality factors and compared to the equivalent parameters for other host glasses. The absorption cross section for the 4I 13/2→ 4I 15/2 transition is determined. Photoluminescence (PL) and its decay behaviour studies were carried out for the transition 4I 13/2→ 4I 15/2. © 2011 Elsevier B.V. All rights reserved.


Fares H.,Center National Of Recherches En Science Des Materiaux | Jlassi I.,Center National Of Recherches En Science Des Materiaux | Elhouichet H.,Center National Of Recherches En Science Des Materiaux | Ferid M.,Center National Of Recherches En Science Des Materiaux
Journal of Non-Crystalline Solids | Year: 2014

Tellurite glasses with the molar composition (89-x) TeO2- 10TiO2-1Nd2O3-xWO3 (x = 0, 10 and 20 mol%) were prepared by the conventional melt-quenching technique. The effects of WO3 concentration on the structural, thermal and optical properties of tellurite glasses have been discussed. From the differential scanning calorimetry measurements, thermal properties such as glass transition temperature Tg, crystallization temperature Tx, and thermal stability ΔT are estimated. It was found that ΔT increases with the increase of WO3 composition which can indicate a reinforcement of the glassy network. Both Raman and FTIR results show that the addition of WO3 induced a depolymerisation of tellurite glass since the Te-O-Te inter-chain linkages are progressively substituted by stronger Te-O-W bridges that are at the origin of the increase of the thermal stability of the glass. The optical band gap energy values corresponding to the direct and indirect allowed transitions and the Urbach energy values of the prepared tellurite glasses have been calculated from optical absorption edges. The results show an important decrease of the optical band gap with the increase of WO3 concentration. It was assigned to W6 + ions that could have a role as network modifier. The Urbach energy was found to decrease with WO3 compositions which suggest the possibility of long range order. The refractive index and extinction coefficient were obtained by spectroscopic ellipsometry. Higher values for the refractive index are recorded due to the high polarizability of non-bridging oxygen. It is observed also that the refractive index, n increases with increasing WO3 content. It is established that there is a trend by which the energy gap decreases with increasing refractive index and increasing the polarizability of the oxide ions. The complex dielectric function ε, relative to each sample, was estimated from regression analysis. The material studied here has potential application as optical fiber. © 2014 Elsevier B.V. All rights reserved.


Fares H.,Center National Of Recherches En Science Des Materiaux | Jlassi I.,Center National Of Recherches En Science Des Materiaux | Hraiech S.,Center National Of Recherches En Science Des Materiaux | Elhouichet H.,Center National Of Recherches En Science Des Materiaux | Ferid M.,Center National Of Recherches En Science Des Materiaux
Journal of Quantitative Spectroscopy and Radiative Transfer | Year: 2014

Different glass matrices doped with Nd3+ have been prepared by the conventional melt quenching method with the molar compositions of (89-x)TeO2-10TiO2-1Nd2O3-xWO3 (x=0, 10 and 20mol%). The XRD, FTIR, absorption spectra, photoluminescence (PL) spectra and luminescence decay curves of glass samples were measured at room temperature and investigated, respectively. The XRD pattern confirms the amorphous nature of the prepared glasses. The free OH- content in the 1.0mol% Nd2O3-doped glass samples has been estimated from their measured Infrared transmittance spectra. Judd-Ofelt (J-O) intensity parameters were derived from the absorption spectrum and used in turn to estimate radiative properties such as radiative transition probabilities (AT), radiative lifetimes (τr) and branching ratios (βJJ') for 4F3/2→4I9/2, 11/2, 13/2 transitions. From the emission spectra, peak wavelength, effective bandwidth (δλeff) and stimulated emission cross-section (σemis) were calculated for the 4F3/2→4I11/2 transition. The values of the stimulated emission cross-section obtained in the present Nd3+-doped tellurite glasses are on the higher side than the values of the reported as well as commercial. The luminescence decay curves for the 4F3/2→4I11/2 transition have been measured to evaluate the quantum efficiency (η). The results show a significant increase of the quantum efficiency (η) with the increases of WO3 concentration. Notably, it is found that the quantum efficiency in the TTNW20 glass is much longer than that in most other glasses which indicates that this glass system could be considered as a good candidate for near-infrared lasers at 1.06μm. © 2014 Elsevier Ltd.


Sdiri N.,Center National Of Recherches En Science Des Materiaux | Elhouichet H.,Center National Of Recherches En Science Des Materiaux | Ferid M.,Center National Of Recherches En Science Des Materiaux
Journal of Non-Crystalline Solids | Year: 2014

Abstract In this paper a set of (95-x) P2O5-xB 2O3-4.9Na2O-0.1Er2O3 (x = 5-10-15-20 mol%) samples was prepared using a conventional melt-quenching technique. A glass ceramic phase was confirmed by X-ray diffraction. Small crystallites at the B2O3 addition were detected by Raman scattering. The glass containing 20 mol% B2O3 shows a high thermal stability with a value ΔT = Tc-Tg exceeding 100 C, where Tg and Tc are the glass transition and crystallization onset temperatures. The Raman spectroscopy measurement shows that BOP bonds were present in the glasses. From the absorption edge studies, the value of the optical band gap Eopt has been evaluated. The decrease in optical band gap values and consequently the decrease in Urbach's energies confirm the less extension of the localized states within the band gap. As a result, there shall be an increase in the order of the glass network. The variation in optical parameters is owing to the substitution of B 2O3 oxides in P2O5-Na 2O-Er2O3 glass network. The fundamental absorption edge for all the glasses was analyzed and the Judd-Ofelt parameters (Ω2, Ω4 and Ω6) were obtained. The PL intensity, the PL life time and the quantum efficiency relative to the 4I13/2 → 4I15/2 (1530 nm) transition of Er3 + were all found to decrease with the addition of B2O3. © 2014 The Authors.


Bekri-Abbes I.,Center National Of Recherches En Science Des Materiaux | Srasra E.,Center National Of Recherches En Science Des Materiaux
Journal of Polymer Research | Year: 2011

Conductive polyaniline has been prepared by solid-solid reaction using ammonium peroxydisulfate as an oxidant. The obtained polymer was examined by X-ray diffraction, UV visible, FTIR spectroscopy, thermogravimetric analysis and impedance spectroscopy. The effect of oxidant/monomer molar ratio (R) on the structure and electrical properties of polymer has been examined. The analyses of X-ray diffraction patterns demonstrated that polyaniline prepared by this method is more crystalline than that obtained by conventional solution method. The FTIR spectroscopy showed that the emeraldine salt has been formed. The electrical properties were measured at different temperatures in the range of 296-523 K. The ac conduction shows a regime of constant dc conductivity at low frequencies and a crossover to a frequency-dependent regime of the type A ωS at high frequencies. © 2010 Springer Science+Business Media B.V.


Jlassi I.,Center National Of Recherches En Science Des Materiaux | Elhouichet H.,Center National Of Recherches En Science Des Materiaux | Hraiech S.,Center National Of Recherches En Science Des Materiaux | Ferid M.,Center National Of Recherches En Science Des Materiaux
Journal of Luminescence | Year: 2012

The 75TeO 220ZnO4Na 2CO 31Er 2O 3 (in molar ratio) glass system was prepared by the conventional melt-quenching method. As such, the samples prepared were investigated by differential scanning calorimetry (DSC), X-ray diffractrometry (XRD), Raman spectroscopy and infrared luminescence. DSC analyses were carried out on our glass at different heating rates between 5 and 20°C/min. The result of the annealing temperature on the spectroscopic properties of Er 3+ in tellurite glasses was discussed. The activation energy, for surface crystallization, was determined graphically from a Kissinger-type plot and had a value about 897.2 kJ/mol. Crystalline phases for both α-TeO 2, γ-TeO 2 and Zn 2Te 3O 8 system were determined by the XRD method and were confirmed by Raman spectroscopy characterizations after heat treatment. The effect of heat treatment on absorption spectra and luminescence properties in the tellurite glass was also investigated. With heat treatment, the ultraviolet absorption edge presented a redshift. As a result, the JuddOfelt (JO) intensity parameters (Ω 2, Ω 4, Ω 6) were determined. The spontaneous emission probabilities of some relevant transitions, the branching ratio and the radiative lifetimes of several excited states of Er 3+ were predicted using intensity JO parameters. The near infrared emission that corresponds to Er 3+: 4I 13/2→ 4I 15/2 can be significantly enhanced after heat treatment. Notably, it is found that the luminescence lifetime in the present system is much longer than that in most other glasses and glass ceramics. A comparative study on luminescence performance suggests that the obtained glass ceramic is a promising material for Er 3+ doped fiber amplifiers. © 2011 Elsevier B.V. All rights reserved.

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