Hajer guermazi | University of Sfax (original) (raw)

Papers by Hajer guermazi

In this paper, Epoxy/ZnO hybrid nanocomposites (EP-ZO-HNCs) were prepared by mechanically dispers... more In this paper, Epoxy/ZnO hybrid nanocomposites (EP-ZO-HNCs) were prepared by mechanically dispersing ZnO nanoparticles into epoxy matrix. The XRD patterns show structural changes depending on the added ZnO composition. The electrical conductivity and conduction mechanisms of EP-ZnO-HNCs are investigated by impedance spectroscopy at various frequencies (40 Hz − 100 MHz), and current-voltage measurements under DC step voltages (100 V− 4 kV). DC conductivity data of EP-ZO-HNCs show a critical percolation threshold for x c = 0.43 wt% of ZnO. Furthermore, the conduction mechanisms, discussed based on current-voltage data, depend on both applied field and ZnO content. At low fields, Ohmic conduction, ensured by free carriers, is prominent, whereas at high fields, the conduction is rather governed by several processes such as: Trap Field Limited conduction (TFLC), Space Charge Limited conduction (SCLC), Schottky, hopping and Mott mechanisms. An agreement between the experimental and theoretical results is obtained. Accordingly, characteristic parameters are computed following fitting models. It was found that adding ZnO favors charge injection under high fields, creates deeper levels in the band gap and decreases the distance between hopping sites.

Materials Science and Engineering: B, 2021

Abstract In this paper, Epoxy/ZnO hybrid nanocomposites (EP-ZO-HNCs) were prepared by mechanicall... more Abstract In this paper, Epoxy/ZnO hybrid nanocomposites (EP-ZO-HNCs) were prepared by mechanically dispersing ZnO nanoparticles into epoxy matrix. The XRD patterns show structural changes depending on the added ZnO composition. The electrical conductivity and conduction mechanisms of EP-ZnO-HNCs are investigated by impedance spectroscopy at various frequencies (40 Hz − 100 MHz), and current–voltage measurements under DC step voltages (100 V−4 kV). DC conductivity data of EP-ZO-HNCs show a critical percolation threshold for xc = 0.43 wt% of ZnO. Furthermore, the conduction mechanisms, discussed based on current–voltage data, depend on both applied field and ZnO content. At low fields, Ohmic conduction, ensured by free carriers, is prominent, whereas at high fields, the conduction is rather governed by several processes such as: Trap Field Limited conduction (TFLC), Space Charge Limited conduction (SCLC), Schottky, hopping and Mott mechanisms. An agreement between the experimental and theoretical results is obtained. Accordingly, characteristic parameters are computed following fitting models. It was found that adding ZnO favors charge injection under high fields, creates deeper levels in the band gap and decreases the distance between hopping sites.

Radiation Effects and Defects in Solids, 2019

In the framework of the ICERR (International CEntres based on Research Reactors) project, the eff... more In the framework of the ICERR (International CEntres based on Research Reactors) project, the effect of neutron/gamma irradiation on material has been studied. In this work, we investigate the mixed neutron/gamma irradiation effects on the optical properties of epoxy resin polymers. Photoluminescence (PL) measurements are used in epoxy resin films irradiated in the dose range from 0 to 900 Gy. For more information about the carriers dynamics, we studied their activation energy and phononic processes through the analysis of the PL spectrum evolution as a function of temperature. Mostly, materials irradiation studies by ionizing sources show a generation of defects and subsequently lead to the damage and degradation on the different properties. In this study we have shown an advantage of neutron/gamma irradiation, it is the improvement of the luminescence properties. The 500 Gy dose has the highest quantum yield at low temperature. But the 600 Gy dose shows the highest yield at room temperature. For the 500 Gy dose, the neutron/gamma treatment mainly favored the activation of carriers from lower to higher levels. On the other side with the 600 Gy dose, there was a combination between the activation of carriers from lower to higher levels and the ionization of trapped electrons in the defects centers.

Optical and Quantum Electronics, 2018

Indigo carmine (IC) is an organic material dye that can be used as an organic semiconductor. The ... more Indigo carmine (IC) is an organic material dye that can be used as an organic semiconductor. The IC powder pellet was characterized by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy, AC\DC electric conductivity and optical diffused reflectance spectroscopy. The XRD measurements revealed that the IC powder is crystallized in triclinic system structure with the space group P 1 and both the optimized lattice and refinement cell parameters have calculated before and after refinement for the first time by using the program Crysfire and Checkcell software. The Kubelka-Munk model was used to determine the band gap energies of the IC powder pellet. Based on this model, the IC powder pellet presents two band gaps equal to 1.982 and 1.689 eV in the studied photon energy ranges. The first optical band gap (1.982 eV) is related to the basic HOMO-LUMO transition, and the other optical transition gap (1.689) is related to the trap inside the & A.

Materials Science in Semiconductor Processing, 2017

Journal of Nanoparticle Research, 2021

The simple and eco-friendly co-precipitation method is used to synthesize nickel molybdate in an ... more The simple and eco-friendly co-precipitation method is used to synthesize nickel molybdate in an aqueous solution at room temperature. The physical properties of NiMoO4 are investigated using several techniques, such as X-ray diffraction (XRD), which perfectly fits the crystalline α-form of NiMoO4. Moreover, scanning electron microscope (SEM) images show nanosheet-like particles. The atomic force microscopy (AFM) measurements reveal high roughness of the particle’s surface. Furthermore, the investigations into the main electronic levels of α-NiMoO4 suggest a strong UV–visible light absorption. The optical band gap is found to be about 2.36 eV. Then, the photocatalytic activity of the synthesized NiMoO4 nanoparticles (NPs) is tested against methylene blue (MB) dye as a pollutant model. The obtained results reveal good capacity of MB degradation even in the dark. It exhibits a degradation efficiency up to 87% within 60 min, under visible-light illumination, and 44% in the dark. The photocatalytic stability of NiMoO4 NPs is studied as well. So, successive photocatalytic cycles show that the photocatalyst is still efficient even after five cycles. The obtained results permit to optimistically consider α-NiMoO4 nanosheets as talented photocatalyst for environmental applications, such as photodegradation of hazardous pollutants.

Journal of Materials Science: Materials in Electronics, 2019

Undoped PVA and Zinc iodide (ZnI 2) inorganic salt doped PVA with different ZnI 2 (1-37) wt% perc... more Undoped PVA and Zinc iodide (ZnI 2) inorganic salt doped PVA with different ZnI 2 (1-37) wt% percentages are novel composite polymer dielectric films have been successfully prepared by the solution cast method. The developed dielectric films were characterized by analyzing the physicochemical phenomenon to study the effect of ZnI 2 inorganic salt concentrations. The XRD histogram explicated the being semi-crystalline nature of PVA polymeric matrix with ZnI 2 inorganic salt doping. The optical UV-Vis-NIR characteristics of the composite dielectric films were measured. The effect of ZnI 2 inorganic salt loading contents increasing on opto-electrical properties such as transmittance, Absorbance, optical band gap in addition to the AC impedance spectroscopy was studied in the polymer composite dielectric film. The modifications in the optical properties of PVA film are attributed to the interaction between the salt molecules and the PVA matrix. The frequency dependent AC\DC electric conductivity at different ZnI 2 content follows and obeyed the Jonscher's universal power law. The data of AC impedance spectroscopy is to map ready the complex generalization of resistance that includes capacitive and inductive effects of the polymer composite dielectrics as a function of the angular frequency. These films with excellent optoelectronic phenomenon beside appreciable flexibilities aid their claims as multifunctional UV shielding devices with enhanced a character of semiconductors.

as well. So, successive photocatalytic cycles show that the photocatalyst is still efficient even... more as well. So, successive photocatalytic cycles show that the photocatalyst is still efficient even after five cycles. The obtained results permit to optimistically consider α-NiMoO 4 nanosheets as talented photocatalyst for environmental applications, such as photodegradation of hazardous pollutants.

RSC Advances

Bacterial contamination and biofilm formation generate severe problems in many fields.

Superlattices and Microstructures, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Journal of Electronic Materials, 2019

Epoxy/ITO nanocomposites containing various filler ITO concentrations by weight were successfully... more Epoxy/ITO nanocomposites containing various filler ITO concentrations by weight were successfully fabricated. Using Differential Scanning Calorimetry (DSC), a thermo-analytical technique used to study the glass transition temperatures, we expected to find a restriction in the molecular mobility of the polymer chains that might confirm the influence of incorporating ITO contents into the epoxy material. Several complementary techniques were investigated, such as dielectric relaxation spectroscopy (DRS) at the range of frequency (10−1–106) Hz and over the temperature range from − 80°C to 240°C, and time-domain spectroscopy (TDS) with frequency domain (10−5–10−1) Hz. The experimental data were investigated and interpreted in terms of various dielectric formalisms. For TDS results, the neat epoxy is affected by the added ITO nanoparticles. In the low-frequency domain of TDS measurements, the depolarization current curves of the nanocomposites are precisely fitted in a parallel circuit (RiCi) association model. The obtained dielectric data of TDS analysis shows two interfacial relaxation processes. The first wide peak was mainly ascribed to the charge accumulations ITO-polymer interfaces and the additional peak can be related to the charge accumulated at the interface material-electrodes. Impedance evaluated data were analyzed using a consistent electrical circuit formalism. From − 80°C to 60°C, the nanocomposites exhibited an ohmic behaviour within the added ITO nanofiller. Between 60°C and 120°C, the nanocomposites exhibit a capacitive contribution behavior which makes the material suitable for capacitors devices. Above 120°C, the Nyquist design illustrations [(− Z″) versus (Z′)] are well theoretical fitted to an equivalent circuit model achieved by impedance with designed parameters: resistance (Rb) and constant phase element (CPE) combinations.

Physica Scripta

Various thickness of Rhodamine B (RhB) laser dye was deposited on epoxy polymeric as a new dielec... more Various thickness of Rhodamine B (RhB) laser dye was deposited on epoxy polymeric as a new dielectric organic substrate by spin coating method for the first time. This study focused on the newly considered RhB dye on an epoxy substrate for wide-scale applications. The thickness effect on structural, optical, and dielectric properties of the hybrid coating films was performed. The XRD patterns of the films indicated a large hump amorphous design and lack of Bragg peak intensity associated with the RhB laser dye, due to amorphous film concentration. From UV-Visible spectroscopy, the optical absorption edge shifts to the higher wavelengths direction (redshift) with the variation in RhB dye thicknesses. It was found that the energy band gap decreased when the RhB dye film thickness changed. The refractive index is an important parameter influencing the optical component design. Their values vary according to each relationship that extremely useful the films in optical devices. Laser pow...

<jats:title>Abstract</jats:title> <jats:p>Various thickness of Rhodamine B (RhB... more <jats:title>Abstract</jats:title> <jats:p>Various thickness of Rhodamine B (RhB) laser dye was deposited on epoxy polymeric as a new dielectric organic substrate by spin coating method for the first time. This study focused on the newly considered RhB dye on an epoxy substrate for wide-scale applications. The thickness effect on structural, optical, and dielectric properties of the hybrid coating films was performed. The XRD patterns of the films indicated a large hump amorphous design and lack of Bragg peak intensity associated with the RhB laser dye, due to amorphous film concentration. From UV-Visible spectroscopy, the optical absorption edge shifts to the higher wavelengths direction (redshift) with the variation in RhB dye thicknesses. It was found that the energy band gap decreased when the RhB dye film thickness changed. The refractive index is an important parameter influencing the optical component design. Their values vary according to each relationship that extremely useful the films in optical devices. Laser power attenuation sensitivity of pure epoxy polymeric substrate and its coating films shows that under reducing the thicknesses of RhB dye, the laser power intensity effect increases. Several dielectric parameters are extracted from the series and parallel capacitance measurements. The present results offer new material films for luminescent energy solar concentrator applications.</jats:p>

Materials Science in Semiconductor Processing, 2017

A successful deposition of undoped and Fluorine doped tin oxide (TO and FTO) nano films at relati... more A successful deposition of undoped and Fluorine doped tin oxide (TO and FTO) nano films at relatively low temperature 250°C on flexible substrate (Polyethyerimide) was obtained using the spray pyrolysis technique. The Fluorine doping effects on the structural, morphological and optical properties were investigated. XRD measurements permit textural characterization, and show that the films have a tetragonal polycrystalline structure. The increase of crystalline size and reduction of defects and strain with Fluorine doping improve the crystalline quality. This is may be due to the substitution of O −2 by F-. Furthermore, the structural changes of the films affected the surface roughness which became rough with the Fluorine. This was confirmed by wettability measurements. Moreover, the gap energy exhibits a slight red-shift with F-doping. The photoluminescence spectra showed that Fluorine doping increased the radiative centers, which is confirmed by structural results. The photocatalytic performance of TO and FTO nanofilms were investigated by degradation of crystal violet dye under UV radiations. Results showed that TO and FTO exhibit high photocatalytic activities, which can be enhanced by H 2 O 2 addition.

Journal of Inorganic and Organometallic Polymers and Materials, 2018

Cadmium sulfide doped Poly(vinyl alcohol) (CdS/PVA) polymeric films have synthesized by using in-... more Cadmium sulfide doped Poly(vinyl alcohol) (CdS/PVA) polymeric films have synthesized by using in-situ polymerization technique and ultrasonic approach at the various molar weight of CdS. Subsequently, CdS/PVA polymeric films have been prepared with the objective of studying the effect of CdS nanoparticles on structural, optical and dielectric properties of PVA matrix films. XRD analysis was used to investigate the structural changes of CdS/PVA polymeric films. XRD study evidently shows a cubic crystal structure for CdS powder with the lattice constants a = 5.818 Å and the space group F-43m. All polymeric films revealed the appearance of smaller new peaks related to the presence of CdS into PVA matrix. The dependence of optical properties was investigated by using UV-vis spectroscopy. The estimated band gaps energies revealed a redshift that confirms the active region in solar cell devices. The optical limiting effect showed a completely UV-Vis blocking of the synthesized polymeric films at the high molar of CdS contents. Dielectric properties were measured by using high-frequency LCR meter (4200-SCS) and were found to be strongly dependent on frequency and molar of CdS concentration. Dielectric permittivities were strongly influenced by the applied angular frequency and the real parts were decreased with increasing the molar CdS concentration. AC conductivity increased with angular frequency and decreased with increase in molar weight of CdS content. The results revealed that all synthesized materials are potentially suitable for optics technology devices.

Journal of Alloys and Compounds, 2019

Effect of Ni doping on the structural, vibrational, optical and magnetic properties of YMn 0.4 Fe... more Effect of Ni doping on the structural, vibrational, optical and magnetic properties of YMn 0.4 Fe 0.6-x Ni x O 3 (0 ≤ x ≤ 0.1) nanoparticles

Journal of Materials Science: Materials in Electronics, 2018

The Mn:ZnO/epoxy nanocomposites (MZO-EP-NCs) resin samples are prepared using the ultrasonication... more The Mn:ZnO/epoxy nanocomposites (MZO-EP-NCs) resin samples are prepared using the ultrasonication method. This work deals with the systematic investigation of microstructural, optical and electrical properties of MZO fillers incorporating to the epoxy resin. These samples are characterized by scanning electron microscopy (SEM), X-ray diffraction and UV-Vis spectroscopy. SEM micrographs revealed that the as-prepared MZO nanocrystals are presented in the spherical clusters. X-ray diffraction indicates that the MZO-EP-NCs samples exhibit the presence of MZO nanocrystals peaks. Optical analyses showed a decrease in the band gap energy with increasing the MZO concentrations and a high UV-absorption of MZO-EP-NCs due to the light scattering due to the incorporating MZO particles in the epoxy. Such changes can be described by the shift of HOMO and LUMO band's transition in the studied samples. Our results support the correlation between structure and optical properties of the mentioned nanocomposites. At high electromagnetic waves, the dielectric permittivities are decreased linearly with the addition of MZO clusters compared to neat epoxy. The obtained optical parameters supporting the improvement of the UV shielding properties of MZO-EP-NCs samples.

Journal of Inorganic and Organometallic Polymers and Materials, 2017

Journal of Inorganic and Organometallic Polymers and Materials

This study begins with a synthesis and characterization of Epoxy/TiO2 composites (Ep–TiO2–Cs) wit... more This study begins with a synthesis and characterization of Epoxy/TiO2 composites (Ep–TiO2–Cs) with different TiO2 fillers. The ultrasonic mixing process was employed to disperse the TiO2 fillers into the epoxy resin matrix. The effect of TiO2 contents on microstructural, optical and electrical properties of the Ep–TiO2–Cs have investigated. Several techniques are now being used to characterize the Ep–TiO2–Cs. The microstructure of fracture surfaces was examined by SEM techniques. It revealed that the as-prepared TiO2 particles are a spherical shape structure. At 5.0 wt% TiO2 fillers, it is evident that these spheres are homogeneously distributed in the epoxy matrix. The XRD study confirms that the particle size generally decreases with increasing the added TiO2 fillers in the epoxy matrix. In the UV-light range, the neat epoxy only blocks UV-light in the range of 200–280 nm, it becomes high UV-light blocker (up to 400 nm) via the addition of TiO2 powder with 5.0 wt% fillers. Moreover, the TiO2 content addition obviously enhanced the UV-Shielding efficiency of the epoxy resin.

In this paper, Epoxy/ZnO hybrid nanocomposites (EP-ZO-HNCs) were prepared by mechanically dispers... more In this paper, Epoxy/ZnO hybrid nanocomposites (EP-ZO-HNCs) were prepared by mechanically dispersing ZnO nanoparticles into epoxy matrix. The XRD patterns show structural changes depending on the added ZnO composition. The electrical conductivity and conduction mechanisms of EP-ZnO-HNCs are investigated by impedance spectroscopy at various frequencies (40 Hz − 100 MHz), and current-voltage measurements under DC step voltages (100 V− 4 kV). DC conductivity data of EP-ZO-HNCs show a critical percolation threshold for x c = 0.43 wt% of ZnO. Furthermore, the conduction mechanisms, discussed based on current-voltage data, depend on both applied field and ZnO content. At low fields, Ohmic conduction, ensured by free carriers, is prominent, whereas at high fields, the conduction is rather governed by several processes such as: Trap Field Limited conduction (TFLC), Space Charge Limited conduction (SCLC), Schottky, hopping and Mott mechanisms. An agreement between the experimental and theoretical results is obtained. Accordingly, characteristic parameters are computed following fitting models. It was found that adding ZnO favors charge injection under high fields, creates deeper levels in the band gap and decreases the distance between hopping sites.

Materials Science and Engineering: B, 2021

Abstract In this paper, Epoxy/ZnO hybrid nanocomposites (EP-ZO-HNCs) were prepared by mechanicall... more Abstract In this paper, Epoxy/ZnO hybrid nanocomposites (EP-ZO-HNCs) were prepared by mechanically dispersing ZnO nanoparticles into epoxy matrix. The XRD patterns show structural changes depending on the added ZnO composition. The electrical conductivity and conduction mechanisms of EP-ZnO-HNCs are investigated by impedance spectroscopy at various frequencies (40 Hz − 100 MHz), and current–voltage measurements under DC step voltages (100 V−4 kV). DC conductivity data of EP-ZO-HNCs show a critical percolation threshold for xc = 0.43 wt% of ZnO. Furthermore, the conduction mechanisms, discussed based on current–voltage data, depend on both applied field and ZnO content. At low fields, Ohmic conduction, ensured by free carriers, is prominent, whereas at high fields, the conduction is rather governed by several processes such as: Trap Field Limited conduction (TFLC), Space Charge Limited conduction (SCLC), Schottky, hopping and Mott mechanisms. An agreement between the experimental and theoretical results is obtained. Accordingly, characteristic parameters are computed following fitting models. It was found that adding ZnO favors charge injection under high fields, creates deeper levels in the band gap and decreases the distance between hopping sites.

Radiation Effects and Defects in Solids, 2019

In the framework of the ICERR (International CEntres based on Research Reactors) project, the eff... more In the framework of the ICERR (International CEntres based on Research Reactors) project, the effect of neutron/gamma irradiation on material has been studied. In this work, we investigate the mixed neutron/gamma irradiation effects on the optical properties of epoxy resin polymers. Photoluminescence (PL) measurements are used in epoxy resin films irradiated in the dose range from 0 to 900 Gy. For more information about the carriers dynamics, we studied their activation energy and phononic processes through the analysis of the PL spectrum evolution as a function of temperature. Mostly, materials irradiation studies by ionizing sources show a generation of defects and subsequently lead to the damage and degradation on the different properties. In this study we have shown an advantage of neutron/gamma irradiation, it is the improvement of the luminescence properties. The 500 Gy dose has the highest quantum yield at low temperature. But the 600 Gy dose shows the highest yield at room temperature. For the 500 Gy dose, the neutron/gamma treatment mainly favored the activation of carriers from lower to higher levels. On the other side with the 600 Gy dose, there was a combination between the activation of carriers from lower to higher levels and the ionization of trapped electrons in the defects centers.

Optical and Quantum Electronics, 2018

Indigo carmine (IC) is an organic material dye that can be used as an organic semiconductor. The ... more Indigo carmine (IC) is an organic material dye that can be used as an organic semiconductor. The IC powder pellet was characterized by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy, AC\DC electric conductivity and optical diffused reflectance spectroscopy. The XRD measurements revealed that the IC powder is crystallized in triclinic system structure with the space group P 1 and both the optimized lattice and refinement cell parameters have calculated before and after refinement for the first time by using the program Crysfire and Checkcell software. The Kubelka-Munk model was used to determine the band gap energies of the IC powder pellet. Based on this model, the IC powder pellet presents two band gaps equal to 1.982 and 1.689 eV in the studied photon energy ranges. The first optical band gap (1.982 eV) is related to the basic HOMO-LUMO transition, and the other optical transition gap (1.689) is related to the trap inside the & A.

Materials Science in Semiconductor Processing, 2017

Journal of Nanoparticle Research, 2021

The simple and eco-friendly co-precipitation method is used to synthesize nickel molybdate in an ... more The simple and eco-friendly co-precipitation method is used to synthesize nickel molybdate in an aqueous solution at room temperature. The physical properties of NiMoO4 are investigated using several techniques, such as X-ray diffraction (XRD), which perfectly fits the crystalline α-form of NiMoO4. Moreover, scanning electron microscope (SEM) images show nanosheet-like particles. The atomic force microscopy (AFM) measurements reveal high roughness of the particle’s surface. Furthermore, the investigations into the main electronic levels of α-NiMoO4 suggest a strong UV–visible light absorption. The optical band gap is found to be about 2.36 eV. Then, the photocatalytic activity of the synthesized NiMoO4 nanoparticles (NPs) is tested against methylene blue (MB) dye as a pollutant model. The obtained results reveal good capacity of MB degradation even in the dark. It exhibits a degradation efficiency up to 87% within 60 min, under visible-light illumination, and 44% in the dark. The photocatalytic stability of NiMoO4 NPs is studied as well. So, successive photocatalytic cycles show that the photocatalyst is still efficient even after five cycles. The obtained results permit to optimistically consider α-NiMoO4 nanosheets as talented photocatalyst for environmental applications, such as photodegradation of hazardous pollutants.

Journal of Materials Science: Materials in Electronics, 2019

Undoped PVA and Zinc iodide (ZnI 2) inorganic salt doped PVA with different ZnI 2 (1-37) wt% perc... more Undoped PVA and Zinc iodide (ZnI 2) inorganic salt doped PVA with different ZnI 2 (1-37) wt% percentages are novel composite polymer dielectric films have been successfully prepared by the solution cast method. The developed dielectric films were characterized by analyzing the physicochemical phenomenon to study the effect of ZnI 2 inorganic salt concentrations. The XRD histogram explicated the being semi-crystalline nature of PVA polymeric matrix with ZnI 2 inorganic salt doping. The optical UV-Vis-NIR characteristics of the composite dielectric films were measured. The effect of ZnI 2 inorganic salt loading contents increasing on opto-electrical properties such as transmittance, Absorbance, optical band gap in addition to the AC impedance spectroscopy was studied in the polymer composite dielectric film. The modifications in the optical properties of PVA film are attributed to the interaction between the salt molecules and the PVA matrix. The frequency dependent AC\DC electric conductivity at different ZnI 2 content follows and obeyed the Jonscher's universal power law. The data of AC impedance spectroscopy is to map ready the complex generalization of resistance that includes capacitive and inductive effects of the polymer composite dielectrics as a function of the angular frequency. These films with excellent optoelectronic phenomenon beside appreciable flexibilities aid their claims as multifunctional UV shielding devices with enhanced a character of semiconductors.

as well. So, successive photocatalytic cycles show that the photocatalyst is still efficient even... more as well. So, successive photocatalytic cycles show that the photocatalyst is still efficient even after five cycles. The obtained results permit to optimistically consider α-NiMoO 4 nanosheets as talented photocatalyst for environmental applications, such as photodegradation of hazardous pollutants.

RSC Advances

Bacterial contamination and biofilm formation generate severe problems in many fields.

Superlattices and Microstructures, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Journal of Electronic Materials, 2019

Epoxy/ITO nanocomposites containing various filler ITO concentrations by weight were successfully... more Epoxy/ITO nanocomposites containing various filler ITO concentrations by weight were successfully fabricated. Using Differential Scanning Calorimetry (DSC), a thermo-analytical technique used to study the glass transition temperatures, we expected to find a restriction in the molecular mobility of the polymer chains that might confirm the influence of incorporating ITO contents into the epoxy material. Several complementary techniques were investigated, such as dielectric relaxation spectroscopy (DRS) at the range of frequency (10−1–106) Hz and over the temperature range from − 80°C to 240°C, and time-domain spectroscopy (TDS) with frequency domain (10−5–10−1) Hz. The experimental data were investigated and interpreted in terms of various dielectric formalisms. For TDS results, the neat epoxy is affected by the added ITO nanoparticles. In the low-frequency domain of TDS measurements, the depolarization current curves of the nanocomposites are precisely fitted in a parallel circuit (RiCi) association model. The obtained dielectric data of TDS analysis shows two interfacial relaxation processes. The first wide peak was mainly ascribed to the charge accumulations ITO-polymer interfaces and the additional peak can be related to the charge accumulated at the interface material-electrodes. Impedance evaluated data were analyzed using a consistent electrical circuit formalism. From − 80°C to 60°C, the nanocomposites exhibited an ohmic behaviour within the added ITO nanofiller. Between 60°C and 120°C, the nanocomposites exhibit a capacitive contribution behavior which makes the material suitable for capacitors devices. Above 120°C, the Nyquist design illustrations [(− Z″) versus (Z′)] are well theoretical fitted to an equivalent circuit model achieved by impedance with designed parameters: resistance (Rb) and constant phase element (CPE) combinations.

Physica Scripta

Various thickness of Rhodamine B (RhB) laser dye was deposited on epoxy polymeric as a new dielec... more Various thickness of Rhodamine B (RhB) laser dye was deposited on epoxy polymeric as a new dielectric organic substrate by spin coating method for the first time. This study focused on the newly considered RhB dye on an epoxy substrate for wide-scale applications. The thickness effect on structural, optical, and dielectric properties of the hybrid coating films was performed. The XRD patterns of the films indicated a large hump amorphous design and lack of Bragg peak intensity associated with the RhB laser dye, due to amorphous film concentration. From UV-Visible spectroscopy, the optical absorption edge shifts to the higher wavelengths direction (redshift) with the variation in RhB dye thicknesses. It was found that the energy band gap decreased when the RhB dye film thickness changed. The refractive index is an important parameter influencing the optical component design. Their values vary according to each relationship that extremely useful the films in optical devices. Laser pow...

<jats:title>Abstract</jats:title> <jats:p>Various thickness of Rhodamine B (RhB... more <jats:title>Abstract</jats:title> <jats:p>Various thickness of Rhodamine B (RhB) laser dye was deposited on epoxy polymeric as a new dielectric organic substrate by spin coating method for the first time. This study focused on the newly considered RhB dye on an epoxy substrate for wide-scale applications. The thickness effect on structural, optical, and dielectric properties of the hybrid coating films was performed. The XRD patterns of the films indicated a large hump amorphous design and lack of Bragg peak intensity associated with the RhB laser dye, due to amorphous film concentration. From UV-Visible spectroscopy, the optical absorption edge shifts to the higher wavelengths direction (redshift) with the variation in RhB dye thicknesses. It was found that the energy band gap decreased when the RhB dye film thickness changed. The refractive index is an important parameter influencing the optical component design. Their values vary according to each relationship that extremely useful the films in optical devices. Laser power attenuation sensitivity of pure epoxy polymeric substrate and its coating films shows that under reducing the thicknesses of RhB dye, the laser power intensity effect increases. Several dielectric parameters are extracted from the series and parallel capacitance measurements. The present results offer new material films for luminescent energy solar concentrator applications.</jats:p>

Materials Science in Semiconductor Processing, 2017

A successful deposition of undoped and Fluorine doped tin oxide (TO and FTO) nano films at relati... more A successful deposition of undoped and Fluorine doped tin oxide (TO and FTO) nano films at relatively low temperature 250°C on flexible substrate (Polyethyerimide) was obtained using the spray pyrolysis technique. The Fluorine doping effects on the structural, morphological and optical properties were investigated. XRD measurements permit textural characterization, and show that the films have a tetragonal polycrystalline structure. The increase of crystalline size and reduction of defects and strain with Fluorine doping improve the crystalline quality. This is may be due to the substitution of O −2 by F-. Furthermore, the structural changes of the films affected the surface roughness which became rough with the Fluorine. This was confirmed by wettability measurements. Moreover, the gap energy exhibits a slight red-shift with F-doping. The photoluminescence spectra showed that Fluorine doping increased the radiative centers, which is confirmed by structural results. The photocatalytic performance of TO and FTO nanofilms were investigated by degradation of crystal violet dye under UV radiations. Results showed that TO and FTO exhibit high photocatalytic activities, which can be enhanced by H 2 O 2 addition.

Journal of Inorganic and Organometallic Polymers and Materials, 2018

Cadmium sulfide doped Poly(vinyl alcohol) (CdS/PVA) polymeric films have synthesized by using in-... more Cadmium sulfide doped Poly(vinyl alcohol) (CdS/PVA) polymeric films have synthesized by using in-situ polymerization technique and ultrasonic approach at the various molar weight of CdS. Subsequently, CdS/PVA polymeric films have been prepared with the objective of studying the effect of CdS nanoparticles on structural, optical and dielectric properties of PVA matrix films. XRD analysis was used to investigate the structural changes of CdS/PVA polymeric films. XRD study evidently shows a cubic crystal structure for CdS powder with the lattice constants a = 5.818 Å and the space group F-43m. All polymeric films revealed the appearance of smaller new peaks related to the presence of CdS into PVA matrix. The dependence of optical properties was investigated by using UV-vis spectroscopy. The estimated band gaps energies revealed a redshift that confirms the active region in solar cell devices. The optical limiting effect showed a completely UV-Vis blocking of the synthesized polymeric films at the high molar of CdS contents. Dielectric properties were measured by using high-frequency LCR meter (4200-SCS) and were found to be strongly dependent on frequency and molar of CdS concentration. Dielectric permittivities were strongly influenced by the applied angular frequency and the real parts were decreased with increasing the molar CdS concentration. AC conductivity increased with angular frequency and decreased with increase in molar weight of CdS content. The results revealed that all synthesized materials are potentially suitable for optics technology devices.

Journal of Alloys and Compounds, 2019

Effect of Ni doping on the structural, vibrational, optical and magnetic properties of YMn 0.4 Fe... more Effect of Ni doping on the structural, vibrational, optical and magnetic properties of YMn 0.4 Fe 0.6-x Ni x O 3 (0 ≤ x ≤ 0.1) nanoparticles

Journal of Materials Science: Materials in Electronics, 2018

The Mn:ZnO/epoxy nanocomposites (MZO-EP-NCs) resin samples are prepared using the ultrasonication... more The Mn:ZnO/epoxy nanocomposites (MZO-EP-NCs) resin samples are prepared using the ultrasonication method. This work deals with the systematic investigation of microstructural, optical and electrical properties of MZO fillers incorporating to the epoxy resin. These samples are characterized by scanning electron microscopy (SEM), X-ray diffraction and UV-Vis spectroscopy. SEM micrographs revealed that the as-prepared MZO nanocrystals are presented in the spherical clusters. X-ray diffraction indicates that the MZO-EP-NCs samples exhibit the presence of MZO nanocrystals peaks. Optical analyses showed a decrease in the band gap energy with increasing the MZO concentrations and a high UV-absorption of MZO-EP-NCs due to the light scattering due to the incorporating MZO particles in the epoxy. Such changes can be described by the shift of HOMO and LUMO band's transition in the studied samples. Our results support the correlation between structure and optical properties of the mentioned nanocomposites. At high electromagnetic waves, the dielectric permittivities are decreased linearly with the addition of MZO clusters compared to neat epoxy. The obtained optical parameters supporting the improvement of the UV shielding properties of MZO-EP-NCs samples.

Journal of Inorganic and Organometallic Polymers and Materials, 2017

Journal of Inorganic and Organometallic Polymers and Materials

This study begins with a synthesis and characterization of Epoxy/TiO2 composites (Ep–TiO2–Cs) wit... more This study begins with a synthesis and characterization of Epoxy/TiO2 composites (Ep–TiO2–Cs) with different TiO2 fillers. The ultrasonic mixing process was employed to disperse the TiO2 fillers into the epoxy resin matrix. The effect of TiO2 contents on microstructural, optical and electrical properties of the Ep–TiO2–Cs have investigated. Several techniques are now being used to characterize the Ep–TiO2–Cs. The microstructure of fracture surfaces was examined by SEM techniques. It revealed that the as-prepared TiO2 particles are a spherical shape structure. At 5.0 wt% TiO2 fillers, it is evident that these spheres are homogeneously distributed in the epoxy matrix. The XRD study confirms that the particle size generally decreases with increasing the added TiO2 fillers in the epoxy matrix. In the UV-light range, the neat epoxy only blocks UV-light in the range of 200–280 nm, it becomes high UV-light blocker (up to 400 nm) via the addition of TiO2 powder with 5.0 wt% fillers. Moreover, the TiO2 content addition obviously enhanced the UV-Shielding efficiency of the epoxy resin.