Browsing by Author "Tala-Ighil, Razika"

Now showing 1 - 20 of 46

Adsorption and dissociation of H2S on the anatase TiO2 (100) surface: DFT + U study
(Iop science, 2018) Nehaoua, N.; Belkada, R.; Tala-Ighil, Razika
This paper discusses the adsorption and dissociation of the hydrogen sulfide (H2S) molecule on the titanium dioxide surface. They were studied by density function theory (DFT). The GGA + U approach was used to analyze the adsorption behavior of the H2S molecule on the TiO2 anatase (100) surface. The results presented include adsorption energies, structural and electronic properties, charge transfer and work function. Different adsorption configurations are considered with coordination of H2S at the surface (Ti5c, (Ti5c)2, O2c and O3c sites). The calculated adsorption energies are -0.31, -0.28, -1.14 and -5.66 eV. The most favorable adsorption sites lead to the dissociation of H2S into HS and H, where the S atom of HS binds to Ti5c or O2c atoms, leaving a dissociated H atom bonded to another O2c site. Analysis of Bader's charges reveals a significant charge transfer between the molecule and the surface of the TiO2 anatase. The adsorption process reduces the work function and bandgap of the system, which improves the photocatalytic properties of TiO2
Characterization and studying of ZnO thin films deposited by spray pyrolysis : effect of annealing temperature
(Elsevier, 2016) Belkhalfa, H.; Ayed, H.; Hafdallah, A.; Aida, M.S.; Tala-Ighil, Razika
Characterization of Thin Layer SnO 2 /Glass by Neutrons Reflectometry
(Scientific.net, 2009) Khelladi, Mohamed Fadel; Izerrouken, M.; Kermadi, Salim; Tala-Ighil, Razika
The thermal annealing behavior of the SnO2 thin films elaborated by sol-gel method has been studied by the neutrons reflectivity technique. From the fit of the experimental data using Parratt32 software program developed at HMI, Berlin, scattering length density, thickness and roughness are extracted. The obtained results show that the film thickness increases with the increasing annealing temperature, and the roughness is higher at 500 °C. Whereas, approximately, the same scattering length density is obtained after each annealing temperature
Contact Resistance Determination For Multi-crystalline Silicon Solar Cells By Using Transmission Line Method (TLM)
(2008) Tala-Ighil, Razika; Sali, S.; Oussalah, Slimane; Boumaour, Messaoud
he main objective in solar cells realization consists in increasing their performances. The mechanisms of this increase obey specific phenomena of physics. There is necessarily a contact resistance value behind each value of conversion efficiency. The question is how to quantify the contact resistance and what is its behaviour with different temperature profiles and consequently with the conversion efficiency. This work responds to all of these questions. We have taken square multicrystalline silicon wafers of 10 cm sides. These wafers have followed the traditional process steps i.e.: chemistry, diffusion, silicon nitride PECVD deposition and metallization of the front grid with TLM (Transmission Line Method) mask. The TLM measures are obtained using a test bench which includes a four-point prober and an analyzer. The contact resistance is deduced by the plot of the resistance versus the TLM line distance. It represents the R(D2), R(D3), R(D23), R(D4) and R(D34) where D2, D3, D23, D4 and D34 are the TLM distances. The TLM resistance is the half of the intersection of the slope R(D) with the y-axis. A profile of the evolution of the contact resistance versus the screen printing temperature annealing from 650°C to 800°C for the multi-crystalline silicon solar cells has been obtained.
Dye Sensitized TiO2 and ZnO Charge Transport Layers for Efficient Planar Perovskite Solar Cells: Experimental and DFT Insights
(Springer link, 2019) Chouk, Rihab; Haouanoh, Djedjiga; Aguir, Chadlia; Bergaoui, Manel; Toubane, Mahdia; Al Bensouici, Fayc; Tala-Ighil, Razika
In this work, the efficiency improvement of planar perovskite solar cells by the introduction of modified electron transport layers (ETLs) is investigated. To this aim, a cobalt complex dye as sensitizer for TiO2, based on Schiff base ligand (Co-NG), and a ZnO layer were prepared by the sol gel method and are tested. The electrodes and the complex are characterized by x-ray diffraction, TGA/DSC and UV–Vis spectroscopy. The photo-physical properties of Co-NG complex investigated at the molecular level show that the dye exhibits good optical behavior with two maxima around 415 nm and 604 nm and a high molar extinction coefficient equal to 27.5 × 103 M−1 cm−1. The influence of sensitization on the optical properties of the ETLs is tested and strong interactions between the dye and the ETLs are found. As a result, the solar cell performances of TiO2/Co-NG and ZnO/Co-NG exhibit a significant efficiency increase equal to 18.94% and 16.32%, respectively, compared to the reference solar cells
Effect of acid nature in the starting solution on surface and photocatalytic properties of TiO2 thin films
(Elsevier, 2014) Bensouici, F.; Souier, Tewfik; Iratni, A.; Dakhel, A.A.; Tala-Ighil, Razika; Bououdina, M.
Effect of back contact material on CZTS solar cells simulated with AMPS
(2015) Tala-Ighil, Razika; Toubane, Mahdia; Bensouici, F.; Slimani, Amel; Haouanoh, Djedjiga; Iratni, A.; Sali, S.
The effect of calcination temperature and SiO2 addition on the optical and structural properties of sol gel TiO2 thin films
(2015) Arabi, N. H.; Iratni, A.; Tala-Ighil, Razika; Capoen, B.; Bouazaoui, M.
The Effect of CO Reducing Atmosphere on the Structural and Optical properties of SnO2: F films Deposited on a Si( N+)/Si(P) solar cell
(2006) Tala-Ighil, Razika; Boumaour, Messaoud; Maallemi, Abderrezak; Melhani, Kheira
Effect of Er doping on the microstructural, optical, and photocatalytic activity of TiO2 thin films
(Iop science, 2018) Abdelali, Aouina; Bensouici, F.; Bououdina, M.; Tala-Ighil, Razika
anostructured Er³⁺ doped TiO2 thin films are deposited onto glass substrate via sol-gel dip-coating followed by calcination at 450 °C for 1 h. X-ray diffraction analysis confirms that the films crystallized within single tetragonal anatase phase. Atomic force microscopy observations reveal that the surface of pure TiO2 is characterized by ninepins then becomes smooth and porous for Er-doped TiO2 thin films, while the roughness decreases drastically from 17.2 to 2.6 nm with increasing Er³⁺ percentage. Wettability tests show a super-hydrophilicity character of 0.2 and 0.3%Er doped TiO2 thin films. UV–vis analysis reveals high transmittance above 85% with the presence of interferences indicating the high quality of films. Meanwhile, the energy band gap decreases slightly from 3.31 eV for un-doped to 3.26 eV for 0.4%Er, with a red-shift in the optical absorption edge. High photocatalytic activity using methylene blue indicator has been achieved for 0.2% Er³⁺–TiO2 thin film, reaching 95% for 3 h.
Effect of Er3+ doping on structural, morphological and photocatalytical properties of ZnO thin films
(IOP Publishing, 2018) Bouhouche, S.; Bensouici, F.; Toubane, Mahdia; Azizi, A.; Otmani, A.; Chebout, K.; Kezzoula, F.; Tala-Ighil, Razika; Bououdina, Mahdia
Effect of H2O Content on Structure and Optical Properties of TiO2 Thin Films Derived by Sol-Gel Dip-Coating Process at Low Temperature
(2008) Kermadi, Salim; Agoudjil, N.; Sali, S.; Tala-Ighil, Razika
Pure TiO2 thin films were prepared on the glass substrates by sol–gel dip coating technique with titanium (IV) isopropoxide including simultaneously acetylacetone and acetic acid as stabilizing reagents. The effect of the amount of water in the sol on structural and optical properties of TiO2 thin films was investigated. The structural and optical properties of post- sintered films for 1 hour at 500°C in air were investigated By X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–Vis spectroscopy and ellipsometry. The results showed a simultaneous appearance of the rutile and the anatase phases with different rutile / anatase proportions for all samples. The increase of the water content leads to the decrease of rutile / anatase proportion. The crystalline size varies from 7.94 to 24.84 nm for the anatase phase and from 17.70 to 22.31 nm for the rutile phase. The optical measurements showed that the structure was strongly influenced by the water / alcoxides molar ratios. In comparison with the bulk material, the TiO2 thin films prepared by this way exhibit low refractive index in the range of 2.15 and high band gap energy narrowing from 3.88 to 3.95 eV for direct allowed transition and from 3.09 to 3.39 eV for indirect allowed transition according to the cristallinity degree and the rutile /anatase weight fraction.
Effect of Thickness on Photocatalytic Activity of TiO2 Thin Films
(Springer link, 2015) Bensouici, F.; Bououdina, Mohamed; Iratni, A.; Tala-Ighil, Razika
Effet du recuit de la métallisation par sérigraphie sur les propriétés optiques des couches minces de ZnO déposées par spray
(2009) Belkhalfa, H.; Tala-Ighil, Razika; Sali, S.; Kermadi, S.; Sili, S.; Boumaour, M.; Tayour, F.; Ait Amar, F.; Si Ahmed, Y.
L’oxyde de zinc est parmi les oxydes transparents et conducteurs les plus prometteurs dans le domaine du photovoltaïque. En effet, il joue le rôle de fenêtre optique permettant de capter plus de photons. Le présent travail consiste à étudier et comprendre le comportement du ZnO déposé par spray pyrolyse, avec le recuit de frittage à hautes températures de la métallisation par sérigraphie. La métallisation par sérigraphie est la technique de fabrication par excellence de cellules solaires à l’échelle industrielle. On se focalise surtout sur les propriétés optiques à partir des spectres de réflexion et de transmission par l’emploi de la méthode de Mueller. Après analyse des résultats, on remarque que l’énergie de gap du ZnO décale vers les basses énergies avec le recuit. Elle démarre de 3,49 eV pour l’échantillon sans recuit à 3,26 eV pour l’échantillon recuit à 900 °C
Efficient planar perovskite solar cells using Schiff base complex as sensitizer for TiO2 and ZnO layershe presence of insulin using rGO/ZnO
(IEEE, 2020) Chouk, Rihab; Haouanoh, Djedjiga; Bergaoui, Manel; Aguir, Chadlia; Tala-Ighil, Razika; Khalfaoui, Mohamed
In the current work, our attention is focused on designing a Schiff base complex derived from ninhydrin and glycine ligand (NG) with Co (II) metal (Co-NG) as sensitizer for TiO 2 and a ZnO electron transport layers, prepared by sol gel method. The two electrodes and complex are characterized by X-ray diffraction and UV-vis spectroscopy. Furthermore, a Density Functional Theory (DFT) calculation is performed to achieve supplemental insights about the optoelectronic properties of Co-NG complex. As a result, the studied compound exhibits a high molar extinction coefficient equal to 27.5 × 10 3 M -1 cm -1 . Moreover, to predict the possibility of introducing the modified electron transporting layers (ETLs) in PSC devices, the optical properties is tested and strong interactions between the dye and the ETLs are founded. Accordingly, a good efficiency enhancement to 18.94 % using TiO 2 /Co-NG layer and 16.32 % using ZnO/Co-NG, respectively, is achieved.
Electrical and morphological study of screen printed silicon solar cells contacts
(2012) Tala-Ighil, Razika; Chelli, F.; Sali, S.; Oussalah, S.; Boumaour, M.; Tayour, F.; Si-Ahmed, Y.
The screen printed contact quality influences directly the mono-crystalline silicon solar cells efficiency. This is the aim of this study. A batch of mono-crystalline silicon wafers have undergone all the technological processes such as chemical cleaning, phosphorus diffusion and finally screen printing metallization. According to the used silver paste technical data, the firing temperature should not be greater than 750°C. This is why for this last step, a temperature swept from 650°C to 750°C has been carried out. The principal purpose of this work is to evaluate the Ag/N+ front contact quality by identifying the specific contact resistance, the resistivity and the morphology of each temperature profile. Transmission line method (TLM) is used as the technique for photovoltaic electrical characterization. It has been found that the best annealing temperature profile is750°C which corresponds to the lowest specific contact resistivity value of 1.65 mcm2. Morphological study shows low contact porosity at 750°C which reflects its good quality
Enhanced nanogenerator by embedding lead-free double perovskite Cs2AgBiBr6 in polymer matrix for hybrid energy harvesting
(Royal Society of Chemistry, 2023) Wang, Mengrou; Wang, Xin; Xu, Yubing; Chai, Shunjie; Zhao, Zhiwei; Li, Qing; Wu, Jun; Chen, Jing; Zhu, Zhuoya; Bae, Byung Seong; Tala-Ighil, Razika; Zhou, Jianming
Mechanical energy harvesters fabricated with halide perovskites display excellent electrical output because of their prominent permittivity. An all-inorganic lead-free double perovskite, Cs2AgBiBr6 (CABB), with competitive performance, excellent environmental stability and non-toxicity can break the confines of practical unavailability. CABB microcrystals, which are effective nucleating agents and dielectric fillers, are embedded into a polyvinylidene-fluoride (PVDF)-matrix as efficient electron-acceptors to induce electro-active PVDF β-phase formation and enhance the composite dielectric constant, which contributes to notable hybrid electric outputs. CABB-PVDF hybrid nanogenerators with the optimal CABB concentration of 20 wt% possess triboelectric and piezoelectric effects, with a nanogenerator with a 1.2 cm × 1.2 cm effective contact area and 70 μm film thickness exhibiting a unique response with an open-circuit voltage of 126 V and a short-current density of 4.67 mA m−2 under a 0.5 Hz mechanical frequency and 4 cm s−1 motion speed. An identical device achieves the highest output power density of 0.39 W m−2 at 8 Hz and 0.64 m s−1, which could light up at least 86 commercial LEDs using a 1 μF capacitor and power small electronic devices such as a timer using 22 μF. The corresponding force sensing is achieved with a different distribution of external forces using a 10 wt% CABB-PVDF composite film. This functional composite maintains its stability and charge retention capacity for effective application in various environmental conditions.
Exceptional photocatalytic performance of hexagonal ZnO nanorods for anionic and cationic dyes degradation
(Elsevier B.V., 2025) Chabira, Fares; Toubane, Mahdia; Tala-Ighil, Razika; Humayun, Muhammad; Ouyang, Chun; Alanazi, Amal Faleh; Bououdina, Mohamed; Kyzas, George Z.
This study presents an in-depth investigation of zinc oxide hexagonal nanorods (ZnO NRs) synthesized via a hydrothermal approach at three pH basic values conducted in high-pressure laboratory reactor provided by Parr Instrument Company. The research evaluates the catalytic properties of the ZnO NRs, highlighting their potential for environmental applications. The as-fabricated samples are characterized by various techniques including the X-ray diffraction (XRD), UV–visible spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) analysis, Field emission-scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDAX) and high-resolution transmission electron microscopy (HR-TEM). Rietveld refinement of X-ray diffraction data reveals the formation of high-purity hexagonal Wurtzite-type ZnO phase. Further, it is investigated that by decreasing the pH values, the grain size of ZnO NRs increases from 25.70 nm to 29.91 nm. SEM analyses further confirmed the hexagonal nanorod-shaped morphology of ZnO. The photocatalytic degradation performance of the as-fabricated ZnO NRs for Methylene Blue (MB) and Methyl Orange (MO) dyes increased with the increase in pH value, reaching almost 95 % and 64 %, respectively, after 30 min of UV irradiation. The optimum degradation is achieved at a pH value of 11.
A first-principles computational and experimental investigation on schiff base cobalt complex towards designing solar cells
(Elsevier, 2019) Choukab, Rihab; Aguira, Chadlia; Haouanohc, Djedjiga; Bergaouia, Manel; Tala-Ighil, Razika
A synthesized cobalt complex (Co-NG) based on a Schiff base, derived from ninhydrin and glycine ligand, with cobalt Co (II) metal is presented. A combined theoretical and experimental study is performed. The Co-NG crystalline structure is obtained from XRD spectra, which reveals that the crystal belongs to the triclinic system. Furthermore, the FT-IR spectrum clearly shows that the complex behaves as tridentates monobasic ONO donor ligand. In addition, the optical observations in different solvents show a good absorption in visible especially in Dimethyl sulfoxide (DMSO) solvent with two maxima around 415 nm and 604 nm. Moreover, the Density Functional Theory (DFT) calculations reveal that the Co-NG complex has an energy gap equal to 2.85 eV, where the LUMO energy of the dye is above the TiO2 conduction band and the HOMO energy is below the electrochemical potential of redox couple I−/I3− in the electrolyte. Finally, some photovoltaic parameters including the electron injection () and the redox process rate (), which are equal to – 0.29 eV and - 1.82 eV, respectively, are estimated. These interesting properties make the Co-NG complex a potential sensitizer for dye sensitized solar cell devices
High temperature annealing of sprayed SnO2 : F layers in a silicon solar cell process with screen-printed contacts
(2006) Tala-Ighil, Razika; Boumaour, M.; Belkaid, M.S.; Mallemi, A.; Melhani, K.; Iratni, A.
In order to improve the solar cell conversion efficiency, a thin film of doped tin oxide (SnO2: F) has been deposited by the spray-pyrolysis technique on a monocrystalline diffused silicon wafer. Subsequently, the layer must undergo the firing step of screen-printed contacts with temperatures up to 830 °C. After annealing, one notices with the naked eye the appearance of speckles disturbing the uniformity of the as-deposited blue-coloured SnO2:F. Characterizations such as XPS, FTIR, RBS, XRD, SEM, Hall Effect, four point probe...etc, are all consistent to reveal a net increase of the SnO2:F layer resistivity which leads to efficiency degradation. Annealing the thin films under CO and 90% N2–10% H2 atmospheres was investigated to seek possibilities to preserve the expected improvements. Unlike forming gas, CO reducing ambient was found to be very effective for the high temperature contact firing with no thin film conductivity deterioration