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Nombre total de résultats : 145
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Synthesis and characterization of Nickel oxide (NiO) thin films

Bouhank .A, Serrar.H, Bellal .Y (2018)
Article de conférence

For the synthesis of Nickel oxide as thin films, with the spray pyrolysis technical as a chemical method of deposit, on ordinary glass substrates heated to a fixed temperature of 500 °C. we use Nickel nitrate hexahydrate (99.5 %, Aldrich) as source precursor, dissolved in distilled water. Nickel oxide is a p-type semiconductor, is an important material because of its large direct optical gap between 3.6 and 4.0 eV; and easy to deposit in thin layers by many techniques, such as sol-gel and spray pyrolysis. Diagrams of X-ray diffraction (XRD), to confirm the formation of the phase have characterized the structure of the films deposited by the pyrolysis spray technique. Where they showed that NiO are nanoparticle films and have preferred orientations according to (111) and grain sizes in the range of 15 to 48 nm. The surface morphology, absorption domain, molecular vibrations were characterized by scanning electron microscopy (SEM), UV-Visible Spectroscopy and Raman spectroscopy.Voir les détails

Mots clés : NiO, Raman, UV-Visible Spectroscopy, XDR

A Copper Oxide (CuO) Thin Films Deposited by Spray Pyrolysis Method

Y. Bellal, A. Bouhank, H. Serrar, T. Tüken, G. Sigircik (2018)
Article de conférence

A simple and low-cost procedure (spray pyrolysis) was used to elaborate copper oxide thin films on ordinary glass substrates. A copper nitrate was used and dissolved in two different solutions (Water, Methanol) S1 and S2 respectively in order to obtain an equal concentration;CS1, S2= 0.5M.The spray pyrolysis deposition made at fixed temperature T= 500°C and different volumes of S1 or S2 on the glass substrates. The X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-vis spectrophotometry were used to determinate the structural, morphological and optical properties of CuO thin films. The X-ray diffraction patterns confirm the presence of the polycrystalline phase of CuO as monoclinic crystal structure with preferential orientation along (110), (002), (111), (200) and (020). Their optical band gaps ranged from 3.95 to 4.02eV for thin films made with S1, and from 1.6 to 1.95eV for thin films made with S2 with a high absorbency in the visible region, which is in agreement with the values of the literature.Voir les détails

Mots clés : Copper oxide, Thin films, Spray pyrolysis, Band Gaps, XRD, SEM.

Elaboration and Characterization of Copper Oxide (CuO) Thin Films Deposited bythe Spray Pyrolysis Method

Y. Bellal, A. Bouhank, H. Serrar (2018)
Article de conférence

In this work, a copper oxide thin films were deposed by a simple and inexpensive technique (spraypyrolysis) on ordinary glass substrates at a fixed temperature T=500°C. and differentconcentration of precursor 15, 30 and 45 ml made with H2O like solvent.The structural, morphological and optical properties of thin films of CuO were studied by X-raydiffraction (XRD), scanning electron microscopy (SEM) and UV-vis spectrophotometry. The Xray diffraction patterns confirm the presence of the polycrystalline phase of CuO as monocliniccrystal structure with preferential orientation along (110), (002), (111) and (020). Their opticalband gaps ranged from 3.95 to 4.02eV with a high absorbency in the visible region.Voir les détails

Mots clés : Copper oxide, Thin films, Spray pyrolysis, Band Gaps, XRD, SEM

Chemical Synthesis and Characterization of nickel oxide as semiconductor thin film and doping agent of titanium dioxide

A.BOUHANK, H.Serrar, Y.BELLAL (2018)
Article de conférence

Nickel oxide (NiO) is a p-type semiconductor , is an important material because of its large direct optical gap between 3.6 and 4.0 eV , of its chemical stability and magnetic device , and easy to deposit in thin film by several chemical techniques. However, it used as a dopant of titanium dioxide.NiO thin films were deposited by spray pyrolysis on ordinary glass substrates heated to a fixed temperature of 500 °C, from a nickel nitrate hexahydrate as a precursor dissolved in distilled water.Titanium dioxide is doped with deferent percentage of NiO, this latter was elaborate with the sol-gel method.The both type of thin film, were characterized by several techniques, Such as X-ray diffraction, scanning electron microscopy, optical absorption, Atomic force microscopy , and Raman spectroscopy.Voir les détails

Mots clés : NiO, TiO2, Dip coating, semiconductor

Electrochimical oxidation of glucose by Ni-Fe nanoparticiles dispersed on polyaniline thin films

D. Lakhdari, A. Guittoum, O.Belgherbi, N. Benbrahim (2018)
Article de conférence

In this work we describe the electrodeposition of Ni–Fe nanostructures on polyanilyne (PAni) as templates. The conditions and parameters influence in the morphology and electrochemical activity of the electrodeposited Ni–Fe nanoparticles.The electrocatalytic properties of Ni–Fe/polyanilyne-modified electrode toward the glucose oxidation were analyzed via cyclic voltammetry and amperometry. The studies showed that Ni–Fe /PAni electrode displayed the highest electrocatalytic activity, attributed to the high density of Ni–Fe nanoparticles deposited on the polyanilyne vibreuse nanotubes support.Voir les détails

Mots clés : Ni–Fe nanoparticles, glucose, Polyanilne, cyclic voltammetry, Electrocatalytic Oxidation

A Copper Oxide (CuO) Thin Films Deposited by the Spray Pyrolysis Method

BELLAL YOUCEF, BOUHANK Antar, SERRAR Hacene (2018)
Article de conférence

A simple and low-cost procedure (spray pyrolysis) were used to elaborate copper oxide thin films on substrates in ordinary glass. a copper nitrate was used and dissolved in two different solutions (Water, Methanol) S1 and S2 respectively in order to obtain an equal concentration;CS1, S2= 0.5M.The spray pyrolysis deposition made at fixed temperature T= 500°C and different volumes of S1 or S2 on the glass substrates. The X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-vis spectrophotometry were used to determinate the structural, morphological and optical properties of CuO thin films. The X-ray diffraction patterns confirm the presence of the polycrystalline phase of CuO as monoclinic crystal structure with preferential orientation along (110), (002), (111), (200) and (020). Their optical band gaps ranged from 3.95 to 4.02eV for thin films made with S1, and from 1.6 to 1.95eV for thin films made with S2 with a high absorbency in the visible region, which is in agreement with the values of the literature.Voir les détails

Mots clés : Copper oxide, Thin films, Spray pyrolysis, Band Gaps, XRD.

ELABORATION ET CARACTERISATION DE MELANGES A BASE DE PVC PARTIELLEMENT BIO-SOURCES

Boussaha BOUCHOUL (2018)
Thése de de doctorat

L’objectif de ce travail est de remplacer les plastifiants toxiques à base de phtalate par des mélanges de plastifiants d’origine biosourcés dans les formulations de poly chlorure de vinyle (PVC). A cet effet, l'huile de tournesol époxydée (HTE) a été synthétisée à partir de l’huile de tournesol (HT). Ensuite l’HTE est transestérifiée pour produire l'ester méthylique de l'huile de tournesol époxydée (EMHTE). L’époxydation et la transestérification sont confirmées par la mesure de l’indice d’oxyrane et par la spectroscopie infrarouge (IRTF). Les mélanges de l’HTE et de l’EMHTE avec le diesters d’isosorbide (DEI) et l'acétylcitrate de tributyle (ATBC) ont été utilisés pour réaliser différentes combinaisons de ces plastifiants dans des formulations à base de PVC. Les propriétés thermiques, mécaniques, morphologiques, rhéologiques et physico-chimiques ont été étudiées en utilisant différents techniques comme la coloration, l'analyse thermogravimétrique (ATG), la calorimétrie différentielle à balayage (DSC), l'analyse thermomécanique dynamique (DMTA), la traction, la microscopie électronique à balayage (MEB), la volatilité, la migration, l’essai sur le mélangeur interne (plastographe) et la transmission de la lumière. Ces caractérisations ont montré que la stabilisation du PVC est améliorée par l'addition de l’HTE ou de l’EMHTE dans les mélanges de plastifiants par rapport au DEHP. Le DEI et l’ATBC diminuent la Tg et la contrainte et ils augmentent l’allongement à la rupture des films de PVC. La perte de masse par volatilité et par migration diminue dans les mélanges plastifiants par rapport à un seul plastifiant. La transmission de la lumière diminue avec la présence de l’HTE et l’EMHTE.Voir les détails

Mots clés : Epoxydation, Transestérification, Plastification, HTE, EMHTE, ATBC, DEI., PVC

Electrochemical Deposition of Copper particles on Polyaniline Thin Films for Nonenzymatic Glucose Sensing

Ouafia BELGHERBI, Dalila Chouder, Delloula LAKHDARI (2018)
Article de conférence

Modi?ed polymer ?lms with metal particles incorporated into the matrix by potentiostatic deposition are known as possible electrocatalysis applications. This work presents some results concerning the electrooxidation of glucose at modi?ed polymer thin ?lm electrodes of copper-polyaniline (Cu-PAni) prepared on an Indium tin oxide (ITO) substrate. The response to glucose of this composite material was tested by cyclic voltammetry method in 0.1 M NaOH solution. The results show good performances and indicated a sensitive oxidation peak current of glucose on the modified electrode.Voir les détails

Mots clés : electrochemical deposition, polyaniline, copper particles, Nonenzymatic sensor, Glucose.

Influence of Applied Potential on the Conductivity of Polypyrrole Thin Films growing on Indium Tin Oxide

S. Laidoudi, C. Dehchar, D. E. Hamza, R. Yekhlef, L. Lamiri (2018)
Article de conférence

As one of the promising conducting polymers (CPs), polypyrrole (PPy) has been extensively used as active electrode material for many applications: anti-corrosive coatings, batteries, electronic devices, sensors and biomaterials. In fact, PPy is a widely studied conductive polymer due to its high environmental, thermal and chemical stability, their good electronic conductivity and ease of synthesis. Its conductivity originates from the ? electrons delocalized over the conjugated system and from the doping ions. PPy thin films can be synthesized on electrodes from organic or aqueous media by chemical and electrochemical methods. Electrochemical deposition offers a versatile and facile method since the film formation and its properties (thickness and surface topography) can be easily controlled by controlling the electropolymerization conditions, such as applied potential, current density, monomer concentration, electrolyte solutions and pH. Recently, it has been reported that properties of PPy films depend significantly on their final morphology. Therefore, synthesis of novel morphologies of PPy deposits could improve some of these properties. In this study, PPy thin films were deposited on indium tin oxide (ITO) electrode under potentiostatic control from a solution containing 0.01 M pyrrole (C4H5N) dissolved in acetonitrile (CH3CN). The influence of the applied anodic potential on the morphology, electrochemical behavior, as well as the electronic conductivity of the resulting PPy films was investigated. For this purpose, PPy films deposition was performed at three applied potentials 0.8, 1 and 1.1 V/SCE for 2 min. The obtained films were characterized by impedance spectroscopy measurements, scanning electron microscopy (SEM), and atomic force microscopy (AFM).Voir les détails

Mots clés : Chronoamperometry, Electrochemical polymerization, Polypyrrole, Thin films

Elaboration électrochimique de nanostructures d’oxyde de cuivre (Cu2O)

Samiha LAIDOUDI (2016)
Thése de de doctorat

Dans ce présent travail, nous avons étudié l’effet du potentiel appliqué sur les différentes propriétésdes nanostructures de Cu2O électrodéposées sur un substrat de FTO à partir d’un bain sulfate. Toutd’abord, nous avons étudié les mécanismes de l’électrodéposition du Cu2O en utilisant les techniquesde la voltamétrie cyclique et la chronoampérométrie. Les mesures de Mott-Schottky ont montré que lesnanostructures du Cu2O électrodéposées à différents potentiels cathodiques possèdent une conductivitéde type p avec une augmentation avec le potentiel de la densité des porteurs de charges de 1.30 à 5.38×1018 cm-3. Les caractérisations morphologiques par AFM présentent un changement remarquable de laforme des grains de Cu2O en fonction du potentiel appliqué. Egalement, la surface des dépôts devientmoins rugueuse lorsque le potentiel appliqué se déplace vers les valeurs les plus négatifs. L’analyse parla diffraction de rayons X a montré que tous les échantillons ont une structure cubique avec uneorientation préférentielle suivant la direction (111). En outre, la taille moyenne des cristallites diminueen augmentant le potentiel. L'analyse par la spectroscopie UV-Vis et la photoluminescence nous apermis de déterminer les propriétés optiques des nanostructures du Cu2O telles que l’absorption, latransmission, l’énergie du gap et les domaines d’émission. La transmission de nos échantillons estélevée est de l’ordre de 70 % dans le visible et le gap optique varie entre 1.61 et 2.24 eV. Laspectroscopie Raman est utilisée pour distinguer les phases présentes dans les nanostructures du Cu2O.Les résultats de l’effet Hall ont confirmé celles obtenus par les mesures de Mott-Schottky.Voir les détails

Mots clés : Cu2O, électrodéposition, Mott-schottky, nanostructures, potentiel cathodique