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Öğe Enhancing photocatalytic efficiency through iron doping: a comprehensive study on zirconium vanadate synthesis and characterization(Springer, 2024) Alyousef, Haifa A.; Hassan, Ahmed M.; Ali, Ahmed S.; Issa, Shams A. M.; Zakaly, Hesham M. H.This study investigated the synthesis, structure, optical properties, and photocatalytic performance of novel Fe-doped zirconium vanadate nano-powders (Fe-doped ZrV2O7 NPs). The nano-powders were synthesized using the hydrothermal method to optimize their photocatalytic efficiency with varying Fe concentrations (0 to 9 mol%). Structural analysis using X-ray diffraction (XRD) revealed that the undoped ZrV2O7 exhibited a monoclinic ZrO2 structure while increasing Fe concentrations introduced new peaks corresponding to the zinc-blende structure of Fe2VO4 and the orthorhombic phase of V2O5. Optical characterization using UV–visible spectroscopy showed that the bandgap decreased from 4.02 eV for undoped samples to 3.11 eV for the sample with nine mol% Fe, improving its light absorption capacity. Photocatalytic experiments were conducted using methylene blue (MB) as the model organic pollutant under visible light irradiation (500 W) at room temperature and neutral pH. Degradation efficiency was evaluated by monitoring the reduction in MB absorbance at 665 nm. The ZrV-9 sample exhibited the highest photocatalytic efficiency, with a degradation rate of 72% within 30 min. Additionally, the catalyst demonstrated excellent stability and recyclability, retaining 90% of its efficiency after five cycles. These findings highlight the potential of Fe-doped ZrV2O7 nano-powders as efficient and durable photocatalysts for organic pollutant degradation under visible light. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.Öğe Exploring the impact of substrate placement on Cu3N thin films as a solar cell window layer: Structural and optical attributes(Elsevier, 2023) Alyousef, Haifa A.; Hassan, A. M.; Zakaly, Hesham M. H.Copper nitride (Cu3N) thin films have garnered significant interest due to their exceptional stability, corrosion resistance, and optical qualities. In this research, Cu3N thin films were produced through reactive dc magnetron sputtering (dcMS) in a nitrogen/argon atmosphere on glass substrates without any external heat treatment. The study examined the effects of substrate positions from the cathode target, and subsequently film thicknesses, on the structure and optical properties of Cu3N thin films. Different methods were employed to examine the structural and optical characteristics of the films, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible-near infrared (UV-vis-NIR) spectrophotometry in the wavelength range of 400-2500 nm. The XRD patterns indicated a cubic crystal structure for the films with a dominant orientation along the (100) plane, while SEM images displayed uniform and smooth surface morphologies for the films. The UV-vis-NIR spectrophotometry findings demonstrated transmittance above 70% in the visible region for the films, and the optical bandgap values ranged between 2.29 and 2.49 eV. The optical conductivity (& sigma;), electrical susceptibility (& chi;c), and optical electronegativity (& eta;opt) have been calculated. Furthermore, the nonlinear optical qualities of Cu3N thin films were discussed, including the nonlinear refractive index (n2), the nonlinear optical susceptibility, and the nonlinear absorption coefficient (& beta;c). The Cu3N thin films showed promising optical properties, suggesting their potential use as a window layer in solar cell technology.Öğe Influence of substrate temperatures on the microstructural, morphological, and optoelectronic characteristics of Cu3N/ITO thin films intended for solar cell applications(Springer, 2024) Alyousef, Haifa A.; Zakaly, Hesham M. H.; Hassan, Ahmed M.Solar cells are crucial for renewable energy, with indium tin oxide (ITO) commonly used as a window layer. Copper nitride (Cu3N) is a promising material, yet research on both materials together is scarce. This study investigates the influence of substrate temperatures on the properties of Cu3N/ITO thin films, a critical factor for solar cell efficiency. Cu3N thin films were deposited onto ITO substrates using rf magnetron sputtering in an argon/nitrogen atmosphere at substrate temperatures ranging from room temperature (RT) to 150 degrees C. We found that increasing the substrate temperature significantly enhanced the microstructural, morphological, and optoelectronic properties of the Cu3N/ITO films. XRD analysis revealed a polycrystalline nature with a cubic phase structure, and the average crystallite size increased from 17 nm (RT) to 37 nm (150 degrees C). SEM images showed a corresponding change in the surface morphology with increasing substrate temperatures. The optical properties of the films were studied in a range between (300 to 2500 nm) using UV-Vis-NIR spectroscopy, which showed a decrease in the optical energy gap from 2.62 eV (RT) to 2.23 eV (150 degrees C), indicating a tunable band structure. Additionally, optoelectronic properties containing optical conductivity, electrical conductivity, optical carrier concentrations, optical mobility, refraction loss, and optical resistivity were significantly affected by substrate temperature. Findings highlight the crucial influence of substrate temperatures and offer substantial potential for improving the efficiency of Cu3N/ITO-based solar cells.Öğe Optimizing the structure and optoelectronic properties of cuprite thin films via a plasma focus device as a solar cell absorber layer(Royal Soc Chemistry, 2024) Hassan, Ahmed M.; Alyousef, Haifa A.; Zakaly, Hesham M. H.Solar cells are of growing importance as a renewable energy source, and cuprite (Cu2O) stands out as a promising material due to its cost-effectiveness, abundance, and appealing optoelectronic characteristics. This research uses diverse analytical methods to adjust the influence of the number of plasma focus shots on Cu2O films' crystal structure, morphology, and optoelectronic attributes. X-ray diffraction revealed that both Cu2O and CuO films exhibited a polycrystalline nature with cubic (111), (110), and (200) orientations. Morphological analysis unveiled that film surface characteristics were impacted by the number of shots, leading to the formation of smaller Cu2O grains as the number of shots increased. The transmittance spectra of Cu2O thin films displayed remarkable optical transparency, approximately 80%. The optical bandgap of the films was determined to be 2.57 eV, decreasing to 2.08 eV with an increase in the number of shots, aligning well with values reported for photovoltaic absorber layers. Optoelectronic properties, including optical and electrical conductivities, optical mobility, optical carrier concentrations, refraction loss, optical resistivity, plasmon, and damping frequencies, were computed. The results underscore the significant impact of the number of plasma focus shots and hold great promise for enhancing the performance of Cu2O-based solar cells.
