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    Characterization of sol-gel derived NiO thin films: Effect of post-heat treatment
    (Yildiz Technical University, 2024) Meriem Blizak, Djanette; Brinis, Drifa
    Nickel Oxide (NiO) thin films have a wide range of applications in the field of photovoltaics and optoelectronics technology, due to their excellent properties. By modifying the composition and state of the structure with heat treatments, most of the properties of the film are improved. Thus, this study aim to show the behavior of NiO thin films with the post-heat treatment. We prepared thin films of nickel oxide (NiO) by the spray pyrolysis method, deposited on glass substrates and heated to different temperatures (200 °C, 250 °C and 300 °C). The obtained samples were characterized by UV-Visible spectroscopy, contact angle measurement and Raman spectroscopy. We found that the transmittance of films increases with the annealing temperature and Urbach energy (disorder) decreases with increasing optics gap and annealing temperature. Also, the contact angle increases with the temperature of the annealing, but the surface remains hydrophilic. Furthermore, the Raman spectrum has shown the presence of the crystalline state and amorphous carbon (graphite).
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    The significant effect of K+ counterion in the enhancement of physicochemical and structural properties of amorphous aluminosilicates xerogels used as catalysts in the transesterification of waste frying oils
    (Taylor & Francis, 2023) Boufellah, Nassima; Aksas, Hammouche
    With the aim of better directing the polycondensation of oligomers during the synthesis of amorphous aluminosilicate xerogels by the sol-gel process using Na2SiO3, we reinforced the sols with Kþ counterion and studied its effect on the physicochemical and structural properties of the xerogels using XRD, FTIR, N2 physisorption, SEM, EDX, and TGA techniques as well as quantitative analysis of the acid sites by N-butylamine adsorption followed by potentiometric titration. Based on the results, the introduction of Kþ generated xerogels with good porosity and conferred resist- ance to matrix cracking. The amorphous character of the xerogels did not change after adding Kþ. FTIR spectra showed that the composition of the xerogels was improved after the addition of Kþ. Cation exchange and sulfur removal were much more efficient in the presence of Kþ which improved the acidity of the xerogels. The best percentages of Si and Al were observed at the Naþ/Kþ ratios of 4 and 1.The enhanced xerogel prepared with Naþ/Kþ ratio of 1 gave a biodiesel yield of 80.44% at the optimum parameters and was used for three reaction cycles without signifi- cant loss of biodiesel yield.
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    Effect of TiN thin films deposited by oblique angle sputter deposition on sol-gel coated TiO2 layers for photocatalytic applications
    (Elsevier, 2024) Naas, Lazhari-Ayoub; Bouaouina, Boudjemaa; Bensouici, Fayçal; Mokeddem, Kamel; Abaidia, Seddik-El-Hak
    TiO2 monolayer and TiN/TiO2 bilayer coatings were deposited on soda-lime glass prepared by mixing two techniques, TiO2 was deposited by sol-gel dip-coating and TiN film was deposited by oblique angle deposition using reactive magnetron sputtering at α=45° Structural analysis showed typical peaks of TiO2 anatase phase and cubic (Na-Cl type) structure of TiN. Roughness value of 3 nm was obtained for the TiN/TiO2 bilayer film with a rise and elongated grains size. It was found that the optical band gap energy decreases after coupling the TiN sub-layer which is explained by the incorporation of N atoms into TiO2 structure. At constant UV irradiation time, the photo-degradation of methylene blue rate increased for TiN/TiO2 film by 4 % compared to TiO2 film
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    Efficient photodegradation of azucryl red by copper-doped TiO2 nanoparticles-experimental and modeling studies
    (Springer, 2021) Kerrami, Ahmed; Khezami, Lotfi; Bououdina, Mohamed; Mahtout, Laila; Modwi, Abueliz; Rabhi, Souhila; Bensouici, Faycal; Belkacemi, Hayet
    This research aims to investigate the effect of copper doping on the photocatalysis performance of TiO2nanoparticles for disposalwastewater from organic pollutants. X-ray diffraction analysis manifests the crystallization of a rutile phase for pure and copper-doped TiO2except for 2% resulting in a rutile-to-anatase phase transformation. The crystallite size is found less affected by Cudoping, i.e., ~30 nm. BET analysis indicates a decrease in the specific surface area as the doping loading increases. Scanningelectron microscopy observations reveal spherical particles at the nanometer range for pure TiO2and then larger agglomerates ofultrafine particles with Cu doping. FTIR analysis notifies the existence of hydroxyl groups, which will promote the photocatalysisprocess. The photodegradation of azucryl red (AR) has been investigated under different conditions; i.e., Cu-loading, initialconcentration of AR, and pH. The kinetics of the photodegradation process is further found to comply with the Lagergren kineticlaw, regardless the experimental conditions. Nevertheless, the photodegradation process is not only controlled by the intra-particle diffusion mechanism, but also by mass transfer through a liquid film boundary. The maximum degradation of AR,i.e., 86%, has been achieved at pH = 5.0 during 60 min of contact time for the 2% Cu doping, with effective regeneration. TheFreundlich model exhibits a better fitting for AR dye photodegradation equilibrium data, compared to Langmuir, Temkin, andDubinin-Radushkevich
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    Synthesis and characterization of ZnO thin film for modeling the effect of its defects on ZnO/Cu2O solar cell EQE
    (Sumy State University, 2021) Chala, S.; Boumaraf, R.; Bouhdjar, A. F.; Bdirina, M.; Labed, M.; Taouririt, T. E.; Elbar, M.; Sengouga, N.; Yakuphanoğlu, F.; Rahmane, S.; Naoui, Y.; Benbouzid, Y.
    Zinc oxide (ZnO) is one of the best transparent conducting oxide (TCO) materials with a wide bandgap and good electrical and optical properties. Its low cost, nontoxicity and transparency in the optical region of the electromagnetic spectrum make it very promising candidate for solar cell applications. In this work, zinc acetate precursor was used to grow a ZnO thin film by using sol-gel spin-coating technique. The surface morphological study using scanning electron microscope (SEM) was carried out to confirm the growth pattern and crystal distribution. The optical properties, transmission (T), reflection (R), optical bandgap (E g ), refractive index (n), and extinction coefficient (k) were extracted and investigated to be used in the simulation of ZnO/Cu 2 O heterostructure solar cell, where ZnO thin film plays a double role: as the TCO window, as well as the emitter of the n-p junction. However, the solar cell showed weak external quantum efficiency (EQE) compared to those prepared by using zinc nitrate and diethyl zinc precursors. TCAD numerical simulation was used to clarify the origin of this weak EQE by taking into account two parameters. The first studied parameter is the root-mean-square interface roughness,  RMS , in Haze modeling approach, H, which describes how much of incident light is scattered at the interface. The second studied parameter is the density of defects in the ZnO bulk with continuous distribution of states in its bandgap similar to an amorphous semiconductor made of tail bands and Gaussian distribution deep level bands. Consequently, and by adjusting and investigating the effect of the  RMS and the constituents of the bandgap states, we were able to obtain a good agreement between simulated and measured EQE characteristics of the solar cell
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    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.
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    Sol-gel synthesis and optical characterization of TiO2 thin films for photovoltaic application
    (2015) Arabi, Nour El Houda; Iratni, Aicha; Tala-Ighil, Razika; Capoen, Bruno; Bouazaoui, Mohamed
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    Neutron characterization of thin layer SnO2/Glass by neutrons reflectometry
    (2009) Khelladi, M. F.; Izerrouken, M.; Kermadi, Salim; Tala-Ighil, Razika; Sali, S.; Boumaour, Messaoud