اطاريح الدكتوراه لفرع الفيزياء التطبيقية
Preparation and characterization of Cu2ZnSnS4 by chemical method for solar cell application
By:Nabaa H. Allawi   Supervised By: Prof. Dr. Selma M. H. Al-Jawad    year:2023Abstract
????
To develop sustainable photovoltaic materials in a competitive powergeneration market, a number of parameters, including cost, resource availability, and environmental constraints, must be taken into consideration in both material selection and processing. Cu2ZnSnS4 (CZTS) is an attractive option for Photovoltaic (PV) applications because, in addition to its material properties, which make it a suitable choice for PV applications, all of its constituent elements are abundant in the crust. This leaves us with the task of synthesizing such a compound in order to increase the quality and performance of devices made from CZTS thin films. A facile one-step hydrothermal method was utilized to prepare Cu2ZnSnS4 film using ethylenediaminetetracetic acid (EDTA) as a complex agent. The efficient Molybdenum oxide layer was also grown by the same step as preparing the Cu2ZnSnS4 film. In this study, the effects of zinc concentrations, copper concentrations, different pH values, and different preparation temperatures on the structural, optical, and electrical properties were studied. Also, Raman analysis and X-ray diffraction supported the creation of polycrystalline kesterite phase Cu2ZnSnS4 films with preferred orientation along (112) plane and showed that structure property alters with work conditions. The thicknesses of Cu2ZnSn4 film were about (1-2) μm. Interestingly, Field emission scanning electron microscopy (FE-SEM) revealed that surface morphology changes as work conditions change. UV-visible analysis showed high and broad absorbance spectra with high absorption coefficient values of more than 104 cm-1 in visible and infrared regions for all samples. The photoluminescence analysis demonstrated a single emission peak located at positions which is quite near to the band gap of ideal kesterite Cu2ZnSnS4 for all samples. Finally, Hall measurement showed that all samples were p-type semiconductors. Also presented that the optimum conditions for synthesizing high-quality CZTS film were (Copper/(Zinc+Tin)=0.79), (Zinc/Tin=1.2), (pH=9), and T=200 0C for 24h. Finally, the best heterojunction solar cell was made with Mo foil /MoO3/CZTS/ Zn0.35Cd0.65S/ZnO/Al configuration. A photovoltaic conversion efficiency of (2.21%) was attained under 100 mW/cm2 with an open-circuit voltage of (0.415) V, short-circuit current density of (14.3) mA/cm2 and a fill factor of (37.4%). The spectral response of CZTS- the based cell showed three response regions and the maximum was at 680 nm.
Preparation of CdTe quantum dots for dye sensitized solar cells applications
By:Ameer Qasim Abd   Supervised By: Assist. Pro f. Dr. Odai N. Salman    year:2023Abstract
????
In this thesis, CdTe Quantum Dots (QDs) were synthesized using Pulse Laser Ablation in Liquid (PLAL) techniques. A cationic solution (CTAB) with a concentration of 0.5 mM and an anionic solution (SDS) with a concentration of 5 mM in distilled water were employed. at energy (100, 200 and irradiation energy 600 mj 6 HZ, number of pulses = 400) QDs of 2 nm to 13 nm formed in the suspended liquid according to TEM images. The distribution of particle diameter followed a log-normal distribution. X-ray Diffraction (XRD) patterns revealed diffraction peaks at 23.8°, 39.6°, and 47.1°, corresponding to Bragg reflections indexed as (111), (220), and (311). The crystal structure of CdTe QDs was found to be cubic, consistent with that of bulk material. Photoluminescence emission from the prepared QDs occurred at wavelengths of 530 nm for CdTe, 528 nm for CTAB-capped CdTe, and SDS-capped CdTe. The optical energy gap (Eg) was determined to be 3.61 eV for CdTe, 3.7 eV for CTAB-capped CdTe, and 3.7 eV for SDS-capped CdTe, respectively. Fourier-Transform Infrared Spectroscopy (FTIR) confirmed the coverage of CTAB and SDS on CdTe nanoparticles. For the fabrication of Dye-Sensitized Solar Cells (DSSCs), TiO2 paste was deposited on Perfluorotin oxide (FTO) substrates using screen printing. Two holes were created for injecting the dye and QDs. Four types of DSSCs were manufactured and characterized: pure CdTe QDs, irradiated CdTe QDs, CTAB-capped CdTe QDs, and SDS-capped CdTe QDs. These were examined for their impact on solar cell properties, including open-circuit voltage, short-circuit current density, fill factor, efficiency, and charge carrier lifetime. The photocurrent density-voltage characteristics for DSSCs with and without CdTe QDs showed an increase in both current and voltage after the addition of CdTe QDs. Open-circuit voltage decay (OCVD) transients of DSSCs with QDs exhibited a more gradual response compared to those without QDs, with OCVD ranging from 1.3 to 1.8 seconds. The open-circuit voltage was found to be linearly dependent on the logarithm of xenon light intensity, and the ideality factor within the range of 5-8. It was observed that CdTe QDs enhanced solar cell parameters, leading to a 19% increase in the density of short-circuit current and an improvement in solar cell efficiency from 0.83% to 2.28%.
Preparation and characterization of doped nano CuS prepared by hydrothermal technique for antibacterial activity
By:Ola Nahedh Hussein   Supervised By: Prof. Dr. Selma M. H. Al –Jawad & Dr. Natheer J. Imran    year:2023Abstract
????
The pure, Fe, Ag, Mn-doped and (Fe/Mn, Ag/Mn) co-doped copper sulfide nanostructures with high surface areas were synthesized by a hydrothermal technique using simple materials. All the samples were prepared and characterized by X-ray diffraction (XRD), Williamson – Hall analysis (W-H), Field-Emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), zeta potential, ultraviolet-visible spectroscopy (UV-vis), and Fourier-transform infrared spectroscopy (FTIR). The XRD patterns indicate that all CuS samples are in hexagonal covellite polycrystalline phases with estimated crystalline sizes of 25.14–11.03 nm. No impurity peaks are observed, indicating the high purity of the final products. The W-H method could be used to measure the lattice strain in the undoped and co-doped samples. It is clear that the values for crystallite size obtained from the W-H plot were higher than those obtained from the Scherrer relation calculation. FESEM measurements showed that the products at different magnifications are composed of microspheres, and the structures that resemble spheres are made up of tens to hundreds of self-assembled nanoplates, perfectly organized and oriented, which are thick at 26–177 nm. EDS spectroscopy was used to identify the existence of components in the prepared samples, the results demonstrating both the purity of the samples and the successful doped of Fe, Ag, and Mn in the CuS host structure. The zeta potential examination was used to estimate the size of the electrostatic potential of the suspension in the solvent. The zeta potential measurements showed that undoped and Fe, Ag doped, and (Ag/Mn) co-doped CuS have a surface charge electrically stable, while the surface charge of the Mn-doped, and (Fe/Mn) co-doped is weakened. Optical measurements indicated the absorbance of CuS samples was highly extended to the visible region in the range 200−600 nm, and this area is important for antibacterial activity. The calculated band gaps were 3.19–2.24 eV. The FTIR peaks indicate the successful preparation of CuS nanostructures. The antibacterial activities of pure CuS doped with Fe, Ag, Mn, and co-doped (Fe/Mn, Ag/Mn) against E. coli, S. aureus, and P. aeruginosa were evaluated by the inhibition zone method. All samples exhibited strong antibacterial activity against all strains. The highest level of inhibition against all strains was observed with a concentration of 4 mg/ml of copper sulfide. Among all the samples that were tested, (Ag/Mn) co-doped copper sulphide showed the highest antibacterial activity against both negative-gram and positive-gram bacteria.
Photo catalysis Degradation Hazardous Pollutants as antibacterial activity
By:Huda Najim Abid   Supervised By: Asst. Prof. Dr. Amar Hadee Jareeze & Prof. Dr. Duha S. Ahmed    year:2022Abstract
????
Photocatalysis has received increasing attention in recent years as an effective technology in wastewater treatment applications. In this project several materials were synthesized by using hydrothermal and used as photocatalysts are Bismuth molybdate (Bi2MoO6), Bismuth Tungstate (Bi₂WO₆), Bismuth Vanadate (BiVO4), Bismuth Oxychloride / Bismuth Vanadate (BiOCl/BiVO4) and Graphitic Carbon Nitride/ Bismuth Vanadate (g-C3N4/BiVO4). The synthesis condition of Bi2MoO6 and Bi2WO6, at pH 2,4,6,8 and 10, While the heterogeneous samples (BiOCl/BiVO4 and g-C3N4/BiVO4) were improved with different BiVO4 content and these samples were tested in the photocatalysis process of Rhodamine B (RhB), methylene orange (MO), and phenol under visible light irradiation. and studied characterize by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Photo electrochemical measurement and UV-Vis spectrometer. First, for Bi2MoO6 and Bi2WO6 samples the photodecomposition of RhB, MO and phenol aqueous solutions under visible light irradiation indicated where effect pH showed enhancements in degradation activity where pH 4 Bi2MoO6 and pH 6 Bi2WO6 of exhibited the highest photocatalytic activity which was 100%, 99% and 88% respectively, of Bi2MoO6 and 93%, 87% and 92% respectively, of Bi2WO6 higher than other samples, respectively Second, the photodecomposition of RhB, and MO aqueous solutions under visible light irradiation indicated that heterojunctions showed enhancements in degradation activity and 0.5 Mm BiOCl/BiVO4 exhibited the highest photocatalytic activity which was 98% and 94% respectively. Which is higher than those of the pure samples (BiOCl and BiVO4), respectively. While at g-C3N4/BiVO4 heterojunctions showed enhancements in degradation activity and 5 wt% g-C3N4/BiVO4 exhibited the highest photocatalytic activity which was 96.8% and 88.4% respectively, higher than those of rest of the heterojunctions, g-C3N4 and BiVO4 samples, respectively. This enhancement could be attributed to the formation of heterojunctions that effectively suppressed the recombination of holes and electrons, where superoxide radicals (O2•) were the main active species during the degradation process. The antibacterial activity of pure samples as compare between Bi2MoO6 and Bi2WO6 at pH 4 and heterojunction 0.5 Mm BiOCl/BiVO4 compared with BiOCl and BiVO4 materials were evaluated by using the Agar well diffusion assay, and colony forming assay. Escherichia coli (E. coli) as Gram-negative and Staphylococcus aureus (S. aureus) as Gram-positive were employed as the target bacteria. at pure samples, the Bi2MoO6 was reported to possess highest antibacterial ability towards E. coli and S. aureus bacteria at three different test concentrations 50,100 and 200 μg\ml after incubation for 24 h. In a heterogeneous sample, it was reported that 0.5 mM BiOCl/BiVO4 had the highest antibacterial ability against Escherichia coli compared to the colonies of BiOCl and BiVO4 inhibiting bacteria where more than 98% of the inactivated bacteria were killed. The photocatalytic properties of NPs were played an important role for inhibiting bacterial growth.
Fabrication of Perovskite Ferroelectric (Ba, Sr) TiO3 Nanorods films for Photovoltaic Applications
By:Thamir Hassen Ali   Supervised By: Prof. Dr. Mukhlis M. Ismail Asst.Prof. & Dr. Odai N. Salman    year:2022Abstract
????
In this study, barium strontium titanate Ba1−xSrxTiO3 (BST) where, (x = 0.2, 0.25 and 0.3) nanostructures were effectively produced on TiO2 nanorod films formed on fluorine tin oxide (FTO) substrates using the hydrothermal process, which is a high-velocity, simple, and economical technology. To identify the optimal condition, the growth characteristics (reaction time and varied concentrations) were studied in this research. The electrical, structural, and optical characteristics of TiO2 and BST films have been widely explored and characterized under a variety of circumstances. X-ray diffraction and field emission scanning electron microscopy measurements were used to analyze the structure and surface morphology of TiO2 and BST nanorod. At 4 hours, BST nanorod films with varied concentrations (0.2, 0.25, and 0.3) were prepared. The production of rutile TiO2 and BST nanorods was verified by X-ray analysis, and the nanorods were orientated in the [002] and [100] directions, with the grown axis perpendicular to the FTO and TiO2 substrate. The crystallinity of TiO2 film was raised by increasing the growing period from 4 to 30 hours, while the crystallinity of BST film was increased by increasing the concentration from 0.2 to 0.3. The film with a concentration of 0.3 exhibited well crystallization. FESEM tests revealed that the nanorods were tetragonal in form, and that the morphology (density, length, and diameter) of the nanorods may be modified by modifying the development period and using varied concentrations of TiO2 and BST. The optical characteristics of TiO2 and BST films, such as transmittance, absorption coefficient, and energy gap, were investigated for a variety of growth times and concentrations. With varying reaction time, the optical energy band gap of TiO2 reduced from (3.14 to 3.0) eV. The optical energy band gap of BST changed from (3.22 to 3.06) eV with various concentration. TiO2 and BST conductivity has been studied. For the various parameters, hall measurements revealed that the TiO2 nanorod is n-type semiconductor. At proper circumstances (10 hours and 0.3) highly ordered vertically aligned TiO2 and BST nanorods may be formed. Solid-state dye-sensitized solar cells (ss-DSSC) and recently developed perovskite solar cells (PSCs) have attracted a great attention in the scientific field of photovoltaics due to their low cost, absence of solvent, simple fabrication and promising power conversion efficiency (PCE) . In these types of solar cell, the dye molecule or the perovskite can harvest the light on the basis of electron excitation. Afterwards, the electron and hole are collected at the charge transport Materials. The effect of Spiro-OMeTAD on the solar cell performance was observed and characterized. The increased conductivity of the Spiro-OMeTAD layer and enhanced charge transfer at the Au/Spiro-OMeTAD interface facilitated the solar cell performance.The solid-state dye-sensitized solar cell (ss-DSSC) demonstrated an overall photoelectric conversion efficiency of 3.14%.
Synthesis of ZnO-Au nanoparticles and study their biomedical applications
By: Taha Mohsin Rashid   Supervised By: Prof. Dr. Uday M. Nayef & Prof. Dr. Majid S. Jabir   year:2021Abstract
????
There are many methods for preparing nanoparticles but the safety, easy, and low-cost methods, become more important and useful. Therefore, Pulse laser ablation in liquid (PLAL) it’s one of an important method distinguished by low cost, safety, and easy. Au NPs and ZnO NPs, and Au/ZnO NPs have been prepared by PLAL as a colloidal solution by different energies with different structures once Au@ZnO as a core/shell nanoparticle (CSNPs) and other Au/ZnO as a nanocomposite (NCs). The characterization for nanoparticles confirms the internationality of materials, XRD results show the phase of Au NPs is cubic and crystallite size is (40.5, 32.78, and 30.94) nm according to energies (400, 600, 800) mJ, respectively. While the phase of ZnO NPs is hexagonal and crystallite size is (38.5, 20.92, and 27) nm according to energies (400, 600, 800) mJ, respectively. Transmitted electronic microscopic (TEM) is used to check the morphology of particles, and UV-Visible Spectroscopy is used to show the absorption peaks, while, Fourier-transform infrared spectroscopy (FTIR) is used to study the types of binding bonds. In this study, antioxidant activity, antibacterial, and anticancer activity have been studied, the result of Au/ZnO CNs is more effective as an antioxidant than Au NPs and ZnO NPs as an individually. The biomedical applications in one of more important filed, therefore, the activity of Au NPs, ZnO NPs, and Au/ZnO NCs as antibacterial appears large inhibition zones for Au/ZnO NCs against S. aureus than E. coli, and also it’s more effective than Au NPs, ZnO NPs as an individually. The cytotoxicity of nanoparticles against two types of cell lines has been studied, first against breast cancer (AMJ13) and second, against oesophagal cancer (SK-GT-4), the percent of kills of AMJ13 is more than SK-GT-4. the cytotoxicity of Au NPs is 78.33 ± 2.404, and the ZnO NPs are 69.67 ± 1.453. While the cytotoxicity of Au/ZnO NCs is more effective than individually of Au NPs and ZnO NPs, and more efficient for penetrated the membrane of the cell line, therefore, increased percent of kills, it was 88.67 ± 1.764. While, the cytotoxicity effect of Au NPs, ZnO NPs, and Au/ZnO NCs against SK-GT-4 cell, Au NPs is 80.00 ± 2.082, and the ZnO NPs is 70.67 ± 1.764. And for Au/ZnO NCs is more effective than individually Au NPs and ZnO NPs, it was 87.67± 1.
Synthesis and Characterization of ZnO nanoparticles for antimicrobial applications
By:Shaymaa Noaman Ismail AL-Jaafari   Supervised By: Dr. Ahmed N. Abd & Dr. Osama Abdul Azeez Dakhil   year:2020Abstract
????
Zinc Oxide Nanoparticles has been prepared at difference methods for antimicrobial applications, also, this study deal with the relationship between the concentration of ZnO NPs (0.01, 0.02, 0.04, and 0.06) mg\ml and their activity in different Bactria and fungi. The first part has been prepared ZnO NPs by (electrolysis method, chemical methods, and aqueous hydrolysis methods), moreover, the standard zinc oxide nanoparticles are used for comparison. The second part is colloidal deposit on a glass by drop casting method with thickness (1 µm100 nm), the ZnO thin film study the characteristics of prepared samples (electrolysis method, chemical methods, and aqueous hydrolysis methods) and a standard zinc oxide nanoparticles. XRD data were useful to calculate the mean crystal size by Scherer equation. The AFM images indicated that the shapes for all samples are spherical shapes furthermore, SEM images with EDX to confirm ZnO form. The optical properties for the freshly ZnO collided were study by The UV-Visible spectroscopy, the results shows the ZnO nanoparticles have a high transparent at the visible range, also the optical energy gap is around (4.3, 5.7) eV due to quantum size effects. The third part has been focused on studying the antimicrobial activity of Zinc Oxid nanoparticles was studied against human pathogenic Microorganisms including Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa; in addition to Candida albicans. The best preparation of zinc oxide nanoparticles according to characterization and medical application (antibacterial and aticandida) was electric methods; the results showed that the best concentration in the inhibition zone is (40) mm in Bactria (E.coli and S. aureus) at the concentration of (0.04) mg/ml, whereas in Candida was (45) mm at concentration of ZnO NPs (0.04) mg/ml.
Synthesis and Characterization of Fe3O4 and Fe3O4 Capped PEG Magnetic Nanoparticles and Study Its Medical Applications
By:Waleed Kamil Abdulkadhim   Supervised By:Prof.Dr. Uday M. Nayef & Prof.Dr.Majid S. Jabir    year:2019Abstract
????
The magnetite nanoparticles (Fe3O4) capped with polyethylene glycol (PEG) were prepared by hydrothermal method, the successful coating of PEG molecules on the surface of (PEG–Fe3O4).These nanoparticles exhibited excellent dispersibility and dissolvability in physiological condition. The obtained nanoparticles were characterized via X-ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, vibrating sample magnetometer (VSM) and thermogravimetry (TG). The average diameter of bare Fe3O4 and PEG- Fe3O4 (Low, medium and high concentrations) magnetic nanoparticles diameter was (9,5,3 and 8)nm respectively and exhibited superparamagnetism and high saturation magnetization at room temperature. Biological effect was studied on two bacterial strains: Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Most of modified magnetite nanoparticles had a significant effect and more on S. aureus and less on E. coli, where as PEG- Fe3O4 magnetic nanoparticles displayed significant effect on the growth rate of bacteria. The present study aimed at investigation of (bare Fe3O4 and PEG–Fe3O4) toxicity using both morphological and functional criteria. The biochemical parameters were assessed by laboratory mice for 7, 14, 21 and 28 days after administration of MNPs. Furthermore, the histological structure of liver, spleen, kidney samples were analyzed. Intravenous infusion of (bare Fe3O4 and PEG–Fe3O4) (1 mg/kg) was not associated with significant changes in biochemical parameters. The histological remained unchanged through the entire observation period. The body weight was non-significant changed through long period after administration of MNPs. The magnetic nanoparticles (bare Fe3O4 and PEG–Fe3O4) under effected induction heating or photothermal are investigated for cancer therapy of in vitro experiments, was measured by MTT assay. The ability of (bare Fe3O4 and PEG–Fe3O4) in induction of apotosis have been done using Acridine orange/ Ethedium bromide stains. Cytotoxicity effect of (bare Fe3O4 and PEG–Fe3O4) against SKOV-3 cells in the presence and absence of laser photothermal therapy and alternating magnetic field (AMF) has been done. Treated of SKOV-3 cells with (bare Fe3O4 and PEG–Fe3O4) significantly increased ROS formation. The heat is found to be rapidly generated by induction heating or near-infrared (NIR) range laser irradiation of magnetic nanoparticles with spherical shape. Both (bare Fe3O4 and PEG–Fe3O4) can be examined by SKOV-3 cancer cells and obviously little affect on cell structure and viability. Where, in another examinations induction heating and laser irradiation at 808 nm was used, however, the SKOV-3 cancer cells viability were effectively suppressed, and the cellular organelles were obviously damaged when incubated with the magnetic nanoparticles after exposure to NIR laser irradiation or (AMF)induction heating. The morphological examination revealed that after a induction heating or photothermal therapy, the SKOV-3 cancer cells structure exhibited discontinue, the cells were significantly wilted and some cells have finals scrappily. Where, PEG-Fe3O4 showed higher cytotoxicity in SKOV-3 cancer cells as compared to bare Fe3O4 , which obviously the more of inhibitions when magnetic nanoparticles treated SKOV-3 cancer cells were exposed to(AMF) induction heating and less of this at exposure to NIR laser irradiation .
Effect of doped Au, Ag with rGO/PS for sensing applications.
By:Haitham Talib Hussein   Supervised By:Prof. Dr. Uday Muhsin Nayef & Assistant.Prof. Dr. Adi M. Abdul Hussien    year:2019Abstract
????
In this work, p-type silicon wafer (111) orientation was used for preparing porous silicon (PS) layers by electrochemical etching (ECE) method, with resistivity of silicon wafer of about 1.5-4Ω.cm.The etching solution consists of hydrofluoric acid and high purity ethanol (C2H5OH) by electrolyte solution concentration HFc=15%. PS samples were prepared at different current densities 2, 4 and 6mA/cm2, and fix time of etching 15min. structural, morphological, chemical, optical and electrical properties are studied by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, photoluminescence (PL) and J-V measurements respectively. The PL experiences are conducted in air and different organic vapor like ethanol, n-hexane, chloroform and H2O vapor. These results showed that the higher PL intensity was at etching current density 4mA/cm2. Synthesis of reduced Graphene oxide (rGO) layers was done by electrochemical exfoliation technique, The SEM, FE-SEM, XRD, Raman spectroscopy and UV-Visible spectroscopy are used for investigation of rGO properties. The SEM images showed the thin sheets of rGO layers. While the Raman test illustrated the D, G and 2D that spectrum peaks at 1350cm-1, 1587cm-1 and 2703cm-1 respectively. The experience of UV-Visible clarified the high transparent of rGO layers. The rGO suspension at concentration was 0. 5 mg/ml was deposited on PS were prepared at different current density 2, 4 and 6mA/cm2 (3 drops). The rGO/PS characteristics were investigated by SEM, AFM, and XRD. While the FTIR examine was investigate the presence of Si-C, C=C, C-O, C-H bonds. The current-voltage measurements features were done in dark and with white light illumination at different power intensities, these results indicated that the rGO layers lead to increase of electrical current. Also the rGO/PS samples showed that the PL intensity increase compare with only PS layer. The higher PL was at etching current 4mA/cm2 which depends on amount of rGO layers inside and on the surface of PS. and affected by organic vapors n-hexane, chloroform, ethanol and H2O vapor. The PL intensity decreased when exposed to this vapors. The amount of decrease was significant when compared with PS layer alone. As the result of PS surface was improved as a vapors sensor. The gold (Au) and silver (Ag) nanoparticles were prepared by laser ablation method. The gold and silver targets were immersed in double distilled deionized water (DDW) using Nd:YAG laser with laser energy 400mJ, number of pulses was 500 and laser wavelength 1064nm. These nanometals were used as doping materials for rGO by ratio 1:9. The FESEM and UV-Visible tests were used for studying the properties of AuNPs, AgNPs and for rGO:nanometals. The suspension of rGO:AuNPs and rGO:AgNPs was deposited on surface of PS (3drops). The characteristics of rGO: MetalNPs/PS was obtained by SEM, AFM, XRD and the FTIR techniques. The PL measurements were done for all rGO:metal nanoparticles samples, they were conducted in air and different organic vapors, these results shown obviously that the PL intensity in air was higher than only PS layer and rGO/PS samples, the quenching of PL when exposed to organic solvents vapors was greater than other samples (PS layer and rGO/PS), the PL quenching value of chloroform was lower than ethanol and greater than n-Hexane.
Spectroscopic Analysis of (Cu, Al and Ag) Plasma Produced by Nd: YAG Laser
By:Noor Malik Saadoon Al-Musawi    Supervised By: Dr.Sabah Habeeb Sabeeh & Dr.Naseer Mahdi Hadi    year:2019Abstract
????
In this work, metallic nanoparticle was prepared by an efficient and size –controlled. Structure and surface morphology of Nanoparticles were characterized by X-ray diffraction (XRD), Atomic Force Microscope and Scanning Electron Microscopy measurements were investigated. Annealing proses was in air at a specifics temperature of 300º C and at a constant time of 75 min the XRD for Cu - NPs technique that showed these films are monoclinic structure with a preferred orientation. Lattice parameters are (a = 4.84, b = 3.47 and c = 5.33) Å. Corresponding to plane (002) and (111), (222) ,(113) the XRD profile of Al-NPs was shown with diffraction peaks of (111), (200), (220) and (311), where the peaks at 111 and 200 were the most intense. The estimated average size corresponding to the most intense crystallographic plane (111) was determined to be 40 nm. The AFM Analysis suggested the size of Al-Ps as 45 nm. Four sharp peaks appeared at 2θ = 38.5º, 44.7º, 64.7º and 77.6º which can be assigned to the (111), (200), (220), and (311) planes of the face centered cubic (FCC) structure of metallic silver. In the second part for diagnosis the metal sample for Al, Ag Cu emission spectroscopy with different laser energy of 81.5,134.5,221 , 240 and 319 mj with a specific distance between the fiber optic and the target with 5mm, where the experiment was in air. Identification for emission spectrum line was analyzed based on the NIST data base. It is noticed that the intensity of spectrum lines, which is in (a.u) , increases with laser energy increase; in addition, the plasma parameter for electron temperature and electron density number also increase that for bulk material .For the enhancement of the LIBS technique we diagnosis the nanoparticles emission spectroscopy and calculated the plasma parameters. It was found the intensity increases in different values higher than for bulk material with the same position for peaks, plasma parameter also increases for electron temperature also reached to saturation value but the values electron density number decrease for NE-LIBS.
Modification and Characterization Carbon Nanomaterials and Hybrid Materials for Antibacterial and Anticancer Activities
By:Mustafa K. A. Mohammed   Supervised By:Dr. M. R. Mohammad & Dr. Duha S. Ahmed    year: 2019Abstract
????
In this study, raw single wall carbon nanotubes (R-SWCNTs) and raw multi wall carbon nanotubes (R-MWCNTs) were chemically functionalized with sulfuric acid (H2SO4) and nitric acid (HNO3) to produce functionalized-SWNTs (F-SWNTs) and functionalized-MWNTs (F-MWNTs). The improving of dispersion ability was investigated with ultraviolet-visible (UV-Vis) spectrophotometer and Zeta potential analysis. The results showed higher absorption band for F-SWNTs and F-MWNTs compared with R-SWNTs and R-MWNTs. In addition, the Zeta potential values were increased from -7 to -42 mV for SWNTs, while for MWNTs from -9 to -51 mV. This indicates that the dispersion ability of SWNTs and MWNTs has been enhanced after acid treatment. The formation of oxygen functional groups (-OH, -COOH) onto the surface of SWNTs and MWNTs after acid treatment was verified by the Fourier transform infrared (FTIR). The X-ray diffraction (XRD) and Raman spectroscopy results showed that the structure of SWNTs and MWNTs was intact after being treated with strong acids. The (002) diffraction peaks for SWNTs and MWNTs were appearing before and after functionalization process. Moreover, the crystalline structure of SWNTs and MWNTs have been observed in the Raman spectra with the D-band, G-band, 2D-band, which are characteristic bands for carbon nanotubes (CNTs) structure. The field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), and energy dispersive spectroscope (EDS) exhibited that the short tubes with less aggregation of SWNTs and MWNTs were observed after being treated in H2SO4/HNO3 mixture. After functionalization and characterization of SWNTs and MWNTs, the preparation of hybrid materials was carried out. The ZnO/Ag-SWNTs, ZnO/Ag-MWNTs, ZnO/Au-SWNTs and ZnO/Au-MWNTs hybrids were prepared by using co-precipitation method. Zinc acetate dehydrate (ZnC4H10O6) and silver nitrate (AgNO3) were used to prepare ZnO/Ag nanoparticles (NPs). While, gold chloride trihydrate (HAuCl4.3H2O) and zinc acetate dehydrate were used to prepare ZnO/Au NPs. The TiO2/Ag-SWNTs and TiO2/Ag-MWNTs hybrids were synthesized by using the sol-gel technique. Titanium isoproproxide (TTIP) and AgNO3 were used as precursors to prepare TiO2/Ag NPs. Higher Zeta potential values were observed for all hybrids in comparison with R-SWNTs and R-MWNTs, but lower than F-SWNTs and F-MWNTs. The UV-Vis measurements suggest that the optical band gap for all hybrids was decreased after loading NPs. The FTIR and Raman spectroscopy results for hybrid materials confirmed the formation of ZnO/Ag, ZnO/Au, and TiO2/Ag NPs with SWNTs and MWNTs. The crystalline structure of hybrid materials was characterized with XRD. The hexagonal wurtzite structure of ZnO was appeared for ZnO/Ag-SWNTs, ZnO/Ag-MWNTs, ZnO/Au-SWNTs and ZnO/Au-MWNTs hybrids. Whereas, the anatase phase of TiO2 was appeared for TiO2/Ag-SWNTs and TiO2/Ag-MWNTs hybrids. The (002) diffraction peaks of CNTs were showed in all hybrid materials. The electron microscopy (FESEM & TEM) images and qualitative analysis of EDS verified loading of ZnO/Ag, ZnO/Au, and TiO2/Ag NPs onto the SWNTs and MWNTs walls. The antibacterial activity of raw-(SWNTs & MWNTs), functionalized-(SWNTs & MWNTs), and hybrid materials were evaluated by using the colony forming assay, and fluorescence microscope. Escherichia coli (E. coli) as Gram-negative and Staphylococcus aureus (S. aureus) as Gram-positive were employed as the target bacteria. The hybrid materials were reported to possess highest antibacterial ability towards E. coli and S. aureus bacteria after incubation for 24 h. Besides, the antibacterial efficiency of hybrid materials was increased after incubation under UV radiation for 2h. The photocatalytic properties of NPs were played an important role for inhibiting bacterial growth. The fluorescence and FESEM images demonstrated that the hybrid materials had the strongest effects on the membrane integrity of E. coli and S. aureus bacteria. The anticancer activity of hybrid materials against human cervical cancer (SiHa) cells and human hepatic (WRL68) cells was assessed by using MTT assay. The cell viability was found to decrease in concentration dependent manner after incubation for 24 h. The SWNTs exhibited higher toxic effect on cancer cells than MWNTs because of difference in physicochemical properties. The hybrid materials have potential to selectively kill cancer cells with less affecting normal cells.
Photothermal Therapy of Cancer Cells Using Direct Coated Gold NPs
By:Lamyaa Fadhil AL-Barram   Supervised By:Dr. Selma M.H. AL-Jawad & Dr. Ali A. Taha    year: 2019Abstract
????
In this study, small-sized gold nanoparticles < 5 nm, coated with two different natural ligand; Bovine Serum Albumin (BSA) and Glutathione (GSH) were applied in cancer treatment, by exploiting the physiochemical properties of them (size, surface charge and the chemistry of the coating ligand). Gold nanoparticles were prepared and characterized using Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), Zeta potential, and UV–Vis spectrophotometer. The nano-complex (BSA- & GSH-AuNPs) was applied against three types of cancer cell lines; Rhabdomyosarcoma (RD), Murine fibroblast (L20B), and RAW 264.7 monocyte-macrophage (MQ), in addition to the normal line; Lymphocytosis cell, in vitro. The cytotoxicity effect of the complex was evaluated by MTT assay, after cells incubation with different concentrations of AuNPs (0.125, 0.25, 0.5, 1 mg/ml) for 24 & 48 h. Cells have been irradiated with continuous low power lasers; green (532 nm , 3.5 W/cm2) and Near-Infrared (NIR) (800 nm, 2.5 W/cm2) at 0.5, 1, 2 and 3 min separately, as photothermal therapy (PTT). One of the primary goals of successful treatment is reducing as possible as the risk and toxicity of the gold nanoparticles introduced into the human body. These goals can be realized by the active targeting of these nanoparticles directly to the cancer rather than normal cells. This targeting have been achieved by exploiting the GSH & BSA coatings as a [pH]-sensitive surfaces. They exhibit fast and reversible response to the [pH] variation conditions between normal (~ 7.4) and cancer cell (6 - 6.5). They would switch their charges from negative carboxylate to positive amine charges when penetrate the cancer cell, leading to localization and aggregation of AuNPs inside the cellular content. Results showed a considerable toxic impact via BSA- & GSH-AuNPs accumulation in cancer cells, alone and in combination with both the green and NIR laser irradiation, where toxicity more than 70% has been attained. Moreover, the results demonstrated that the smaller sized GSH-AuNPs (~3nm) exhibit more selective targeting and toxicity effect in cancer cells than BSA-AuNPs (≥ 3nm) at all nanoparticles concentrations, by the impact of the isoelectric point (IP) impact of GSH (~ 6) that is a near value of the [pH] of the cancer cell, in comparison with that of BSA (~ 5). Whereas no toxic effect has been investigated for normal cells. Another substantial targeting for cancer cells was by conjugating trans-acting activator of transcription TAT-Cell Penetrating Peptide (TAT-CPP) with BSA- & GSH-AuNPs. The binding efficiency of TAT-AuNPs was tested using Dynamic Light Scattering (DLS), UV–Vis spectrophotometer and Zeta potential. The nano-complex TAT-CPP (BSA- & GSH-AuNPs) was applied against cancer lines, in vitro. Cytotoxicity effect was evaluated again by MTT assay after 24 and 48 h incubation time for 0.125, 0.25, 0.5 and 1 mg/ml concentration. Results demonstrated that TAT-(BSA-AuNPs) exhibit significant toxicity for cancer cell lines. The effects of TAT-CPP have improved cancer cell reduction, where cytotoxicity more than 80% has been achieved. While after they irradiated by the two lasers, the toxicity reached to 90% especially at 3 min. TAT-AuNPs are emerging as a promising agent in the specific delivery and off-target eliminating. A proportionally relation of cellular death to AuNPs concentration, exposure time, incubation period and Light-to-heat conversion efficiency have been demonstrated. The efficiency of the cellular killing was featured distinctly at 1 mg/ml concentration, 3 min irradiation time & 48 h incubation period, at all experiment conditions. As a result , the small-sized AuNPs was a serious agent for developing the safety issues of photothermal cancer treatment by: the selective targeting of the cancer rather than normal cells. reducing the NPs toxicity by size overlapping with the renal clearance barrier of kidney filtration (~ 5.5 nm). and promoting the photothermal performance in the NIR region, by the influence of size increasing via the self-assembly of the small AuNPs into large clusters, in which light penetration into deep cancer regions have more interested. This study promises to achieve the simplicity and facility in cancer therapy, where the small-sized AuNPs acts as a simple therapeutic tool for cancer diseases that target the deep, irregular, and complicated cancer regions in the human body, and could replace other cancer treatment techniques, even dispense the laser irradiation in the phototherml therapy.
Fabrication of Perovskite Solar Cell and Studying Some of Its Properties
By:Ali Kadim Hantoosh   Supervised By: Dr. Mohammed S. Mehde & Dr. Abdulnasser M. Al-Gebori   year: 2019Abstract
????
In this work, compact Titanium dioxide (c-TiO2), meso-porous Titanium dioxide (mp-TiO2) and Methylammonium Lead Tri-Iodide (CH3NH3PbI3) films were prepared by spin coating method under different fabrication parameters of the CH3NH3PbI3 films. The aim of fabricating these films was to make perovskite solar cell. Many characterization measurements were achieved on the deposited CH3NH3PbI3 films in order to study the change that resulted from different parameters. The X-ray diffraction (XRD) measurements revealed that the lattice constants of the fabricated CH3NH3PbI3 films were close to the standard values when the films prepared at these parameters (annealing temperature of 100oC, rotation speed of 4000 rpm, spinning time of 60s and the anti-solvent was diethyl ether). The Atomic Force Microscope (AFM) measurements were conducted in order to study the morphology of the fabricated CH3NH3PbI3 films at different scale, these results showed that the grain size of the CH3NH3PbI3 films is in the range between about 160nm to 210nm. Moreover, AFM images showed that the most surface of the films had high degree of regularity and full coverage area. The field emission-scanning electron microscope (FE-SEM) results of the fabricated CH3NH3PbI3 films were well agreed to the AFM result especially in the grains shape and distribution. Absorption measurements have been done to determine the variation of the energy gap and absorption coefficient at different fabrication conditions of the CH3NH3PbI3 films. The structure form of the perovskite solar cells were FTO/c-TiO2/mp-TiO2/CH3NH3PbI3/Au. The capacitance-Voltage (C-V) measurements were achieved to determine the built-in potential, which found to have the highest value when using the Toluene as an anti-solvent during the synthesis of the perovskite layer. In addition, the Current density-Voltage (J-V) measurements in dark conditions have been conducted to compute the ideality factor and the saturation current, which are considered important parameters that influence the characteristics of the solar cells. The best solar cell efficiency was obtained at annealing temperature of 100oC, spinning time of 60s, spinning speed of 4000 rpm and anti-solvent of Diethyl ether with these parameters: Jsc= 12.188 mA/cm-2, Voc= 0.859 V, , FF= 0.57 and efficiency 5.85%.
Preparation and Characterization of Nano - Graphene Oxide by Hummer Method for Antibacterial Activity
By: Russel Rushdi Ghanim   Supervised By: Dr. Mohammad R. Mohammad & Dr. Adi M. Abdul Hussien   year:2019Abstract
????
The graphene oxide (GO) nanosheets have been prepared by Hummer's method, which represents an easy and efficient technique. Alternations have been done to simplify this method to prepare the GO nanosheets with a novel way without a need to add sodium nitrate (NaNO3). Also this preparation has been achieved at room temperature without a need to water bath at temperatures of 35 °C and 98 °C. The structural, spectral, and morphological properties of the synthesis GO nanosheets were characterized by using XRD, EDS, Raman, FTIR, UV-Vis, FE-SEM, and AFM techniques. The x-ray diffraction (XRD) has been used to study the crystal structure of GO nanosheets, orientations, number of layers (sheets), and grain size. The GO nanosheets were observed, and identified by energy dispersive spectroscopy (EDS) analysis, which consist of carbon and oxygen atoms. Raman spectroscopy has been used to identify the ordered and disordered structure of GO nanosheets (functional groups). Fourier transform-infrared spectroscopy (FTIR) has confirmed the existence of the oxygen containing functional groups of the GO nanosheets. The ultraviolet-visible (UV-Vis) absorption spectrum shows two peaks, one in UV region and the other band in visible region, belong to the electronic transitions π→π*, and n→π*, respectively. In addition, the field emission-scanning electron microscope (FE-SEM) shows the morphology and the cross section of GO, which indicates that the nanomaterial takes the sheet shape (layer structure (2D)). II Moreover, the grain size of GO nanosheets has been measured by atomic force microscope (AFM) to be about 67.38 nm. The antibacterial activity of GO nansheets against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were investigated for Gram-negative and Gram-positive bacteria, respectively. The well diffusion method, the colony forming units (CFUs) assay, minimum inhibitory concentration (MIC), morphological change, and the cell viability analysis by using florescent microscope, have been studied. It has been found that the lowest concentration inhibited the bacterial growth, were 125 μg ml-1 for E. coli and 62.5 μg ml-1 for S. aureus. The cell viability analysis was confirmed the damage, which has been occurred on bacterial nucleic acid for the two types of bacteria. The results of the present work offer a novel assay to prepare GO nanosheets, which could be used as novel antibacterial agent in future.
Wire Explosion Technique for Synthesis of Cu Nano Powder
By:Mustafa Mohammed Ridha Sabhan Al-waeli   Supervised By: Assistant Professor Dr. Sabah Habeeb Sabeeh & Chief Researchers Dr. Naseer Mahdi Hadi    year:2019Abstract
????
In this thesis, for the first time in Iraq wires explosion technique for copper nanopowder production was constructed and developed, using Q-switch Nd:YAG laser with wavelength of (1064 nm) and pulse energy of (500 mJ) for ignited the explosion system. The technique has various features that make it different and superior to other techniques, it’s consume less time, high product rate, ecologically safe, efficient for prepared of nanopowders with high purity and large scale product. The development of ignition switch by laser ignition led to stabilization of pulsed current form through electrical discharge, improving instantaneous discharge and disposal of partial discharge phenomenon in capacitor, thereby improving characteristics of the nanopowder by this way, unlike the traditional method that used electric ignited in explosion technique. A nanopowder has been produced via this system using high purity copper wire (99%) with the dimensions (0.2 mm diameter, 30 mm length), under (2.25, 4, 4.5, 7, 8.3, 9.5, 9.6 kV) of explosion voltages and capacitors of (2.2, 4.4, 20 and 40 µF), inside evacuated chamber with ultimate pressure of (10-2 mbar) and then chamber filled with argon gas with ultimate pressure of (2 bar). The structural characteristics of the prepared copper nanopowder was characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Energy Dispersed X-Ray Spectroscopy (EDS). X-Ray Diffraction (XRD) inspection was performed to obtain the structural information of the samples. The XRD results showed that the copper nanopowder has a polycrystalline structure with cubic system and the obtained peaks were a matching with standard values card. Scanning Electron Microscopy (SEM) inspection was also employed to study the surface morphology of the samples. The SEM results revealed the formation of homogeneous spherical and semi spherical nanoparticles with regular forms compacted with each other within very simple agglomeration levels which express the ideal state of particles shapes and sizes. These results were obtained only via dependence of the developed wires explosion technique with laser ignited in this thesis. Atomic Force Microscopy (AFM) inspection results showed existence of compacted small clusters of the prepared copper nanopowder. The highest value of roughness was (500 nm) for the Cu NPs sample which prepared by laser ignited wire explosion technique with 150 J and 8.3 kV, while the lowest value was (60 nm) for the Cu NPs sample which prepared by laser ignited wire explosion technique with 100 J, and 2.25 kV. The highest value of average diameter was (95 nm) for the Cu NPs sample which prepared by laser ignited wire explosion technique with 200 J and 9.6 kV and the lowest value was (21 nm) for the Cu NPs sample which prepared by laser ignited wire explosion technique with 200 J and 4.5 kV. Energy Dispersed X-Ray Spectroscopy (EDS) results showed that the produced copper nanopowder percentages at different energies were (98% at 100 J, 96.7% at 150 J, 97% at 200 J and 95.39%. at 490 J). The maximum absorption range (200-1100 nm) of Cu NPs was (52%) at explosion energy of 490 J and wavelength of 280 nm. The prepared Cu nanopowders had excellent reliability after one year of inspection.
Preparation and Characterization of PAni / Ferromagnetic/ Ferroelectric Composites for Electromagnetic Shielding Behavior
By:Jameel Mohammed Ameen Sulaiman   Supervised By: Assistant professor Dr. Sewench N. Rafeeq & Assistant professor Dr.Mukils M. Ismail    year: 2018Abstract
????
The study search include preparing three components; conducting polymer (Polyaniline doped with Para toluene sulphonic acid) prepared by substance oxidative polymerization of aniline in aqueous medium with ammonium peroxydisulphate as an oxidant, ferrimagnetic cobalt ferrite (CoFe2O4) & cobalt-zinc ferrites (CoxZn1-xFe2O4) at (x= 0.5, 0.6, 0.7) prepared by (sol-gel) method and ferroelectric barium titanate (BaTiO3) performed in co-precipitation (wet-chemical) preparation method. The three components were thoroughly mixed in different ratios (9:1, 3:1, 1:1, 1:3, 4.5:4.5:1, 1.5:1.5:1, 1:1:2, 1:1:3) which is called ananocomposite, are widely used in favor useful of the absorption of large number microwaves in frequency range (8-12) GHz The as-synthesized light nanocomposites matter was characterized by X- Ray Diffraction (XRD), Atomic Force Microscope (AFM), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and recently a microwave vector network analyzer (VNA) at 8-12 GHz. The mechanism of microwave absorption was obviously described with the help of real and imaginary parts of permittivity and permeability therefore the Nicholson–Ross–Weir method was applied to determine the real and imaginary parts of complex relative permittivity (εr'-jεr'') and permeability (μr'-jμr''). Results, of the samples with ratio weight (1:1) showed maximum absorption at frequency range (8-12) GHz. The reflection loss (R.L) showed for (cobalt ferrite / polyaniline) was (-28.35 dB) (>99.6 % power absorption) at 8.1 GHz, which was able to utilize as advanced radar IV absorbing materials. This value was decreased to (-9.1 dB) ( 88% power absorption) at 9.1 GHz and to (-9.6 dB) (>90% power absorption) at 11.2 GHz. i.e., the composite (cobalt ferrite / polyaniline) was suitable in life application for building or cell phone above 9 GHz. Result, of the (R.L) for the composite (cobalt-zinc ferrite / polyaniline) with ratio (1:1) was reversed from the previous one (-2.3 dB) (>40% power absorption) at 8.1 GHz, (-17.08 dB) (98 % power absorption) at 9 GHz, and (-24.86 dB) (99.73 % power absorption) at 10.9 GHz, therefore the composite (cobalt-zinc ferrite / polyaniline) was more useful in military applications as a shielding material. Results, for the composite (cobalt ferrite / barium titanate / polyaniline) with ratio (1:1:3) was the best than other their subgroup, (-5.47 dB) (>70% power absorption) at 8.1 GHz, (-8.37 dB) (>87 % power absorption) at 9 GHz and (-8.87 dB) (>90 % power absorption) at 11.6 GHz, but these results were still more less in power absorption than the composite (cobalt -zinc ferrite) with ratio (1:1). Results, of the composite (cobalt-zinc ferrite / barium titanate / polyaniline) with ratio (1:1:2) are completely different and the (R.L) have best values than all other samples research, it was (-5.56 dB) (>74% power absorption) at 8.1 GHz, (-17.75 dB) (>98 % power absorption) at 9 GHz and (-33.27 dB) (99.95 % power absorption) at 11.3 GHz, and these significance recorded maximum power absorption in microwave X-band which can be depended in different and wide application shielding; military applications such as radar absorption materials, in medical field, communications …etc. The means of microwave absorption is mostly owing to the dielectric loss quite than magnetic loss.
Characterization of doped and undoped Ni-Zn ferrite for super paramagnetic approach
By:Nasma A. Jaber   Supervised By: Dr. Mukhlis M. Ismail    year:2018Abstract
????
In this thesis, there are two parts of preparation nickel ferrite nano-powder using Sol-gel auto combustion method. First: Zinc ions is substituted nickel ferrite according to the formula Ni1-xZnxFe2O4 where x was the ratio of zinc ions Zn2+ (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5). Second: lithium doped nickel-zinc ferrite with formulas {Ni0.9−2y Zn0.1LiyFe2+yO4, Ni0.8−2y Zn0.2LiyFe2+yO4 and Ni0.7−2y Zn0.3LiyFe2+yO4} where y is the ratio of lithium ions Li+ (y = 0, 0.01, 0.02, 0.03 and 0.04). The structure, morphology, elastic, dielectric and magnetic properties were studied via X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), Inductance-Capacitance-Resistance (LCR) meter and vibrating sample magnetometer (VSM). X-ray diffraction results showed that the prepared spinel ferrite had cubic spinel structure with space group Fd-3m. The experimental values of the lattice constant (aexp) were increases from 8.34 to 8.397 Å with the addition of zinc ions but it was decreases with doped Li ions. It was found the decreasing of the crystallite size with addition of zinc and lithium ions concentration. The radius of tetrahedral (rtet) and octahedral (roct) site, oxygen position parameter (U) and jump length (J) were computed from cation distribution. FTIR measurement exhibit two absorption bands (ʋ1 and ʋ2) around 400-600 cm-1 which confirms the existence of tetrahedral and octahedral sites of ferrite. The force constant, elastic wave velocity, bulk modulus and young's modulus are reported. It was found that the values of the calculated elastic constant for Ni-Zn ferrite nanoparticle in a good agreement compared with those of bulk material. The dielectric parameters [dissipation factor (Df), the dielectric constant (Ԑ') and ac conductivity (σac)] of spinel ferrite nano-powder had been measured. There were decreases by increasing frequency for spinel composite. The saturation of magnetization, remiensis, coersivity, the magnetic moment, anisotropy constant and permeability were found from hysteresis loop. It was found that the value of saturation magnetization for nickel ferrite is equal to (Ms =46.8 emu/gm). This value increases when addition zinc ions and became maximum at x = 0.3 (Ms =59.64 emu/gm) and then decrease. The saturation magnetization and coercivity varied from (Ms= 13.9 to 67.56 emu/gm) and (Hc=65 to 133 Oe) for lithium doped Ni-Zn ferrite. The obtained values of squareness ratio (Mr/Ms) were varied from 0.09 to 0.36 this means that the preparation material have single domain structures. The prepared sample (Ni-Zn ferrite with x=0.5) and (Li-Ni-Zn ferrite at x=0.3, y=0.04) suitable for superparamagnetic applications which have low coersivity and crystallite size.
Synthesis and Study the Structural and Optical Properties of TiO2 Nanorod Arrays Decorated with CdS Nanoparticle
By:Natheer Jamal Imran   Supervised By: Prof. Dr.Mohammad R. Mohammad & Asst. Prof. Dr.Selma M.H. Al-Jawad   year:2017Abstract
????
In this work TiO2 nanostructure thin films were prepared using different deposition methods (chemical bath deposition, hydrothermal, and anodization). Many growth parameters have been considered in this work to specify the optimum condition, for CBD namely (pH, deposition time, and concentration), different deposition times for hydrothermal method, and for anodization technique different electrolytes solutions were used. Annealing in air at different temperatures of (400,500, and 600) °C at constant time (1 hour) were achieved for all films deposited by different methods. The structure and morphology of (XRD, SEM, EDX, and AFM), and optical (UV-Visible spectroscopy, PL spectroscopy, and Spectral Response), properties of nanostructures TiO2 films were investigated and analyzed. XRD analysis of all deposited films has confirmed the formation of polycrystalline-tetragonal phase (anatase, and rutile) with increasing in crystalline size, with increasing annealing temperatures. As a result; it has been found that all films have nanostructures nature. SEM measurements of all TiO2 films show nanostructure shaped (films deposited by CBD show nanorods shapes, films deposited by hydrothermal method show nanofibers shapes, and films deposited by anodizatin technique show nanotubes shapes. EDX analysis confirmed the stoichiometry ratio between Ti, and O to be 1:2 to produced TiO2 film. Optical measurements (absorbance, and energy band gap) were carried out. All absorption edges are located at UV-region, and Eg has higher values compared with Eg for bulk TiO2 film. PL measurement results show two peaks one located at UV-region pointing to energy band gap for TiO2 films; second one is located at visible region pointing to impurities in films. Spectral response measurements show photocurrent peaks for all TiO2 structure films deposited by different methods centered at UV-region. Second step is depositing (decorated) CdS NPs layers on TiO2 films deposited by two methods CBD, and successive ionic layer adsorption and reaction (SILAR) (with 1, and 10 cycles), to synthesize TiO2/CdS core-shell composite films. XRD analysis of all deposited films has confirmed the formation of two phases one is tetragonal phase (anatase, and rutile) for TiO2, and second hexagonal phase which belong to CdS layer. SEM images show change in morphology of CdS from rose like shape to spherical grained CdS particle. And for all films the nanoparticles cover all TiO2 films. For optical measurements, all absorption edge values for TiO2/CdS films showed red-shifted towards visible region, and Eg has decrease in values compared with TiO2 nano structure films. An example of the value of Eg for TiO2/CdS (CBD/CBD) was about (2.9) eV, and this mean film absorbs in visible region besides UV-region. PL measurement results of TiO2/CdS core-shell show two peaks, one is located at UV-region pointed to energy band gap for TiO2 nano films, and second one is located at visible region pointing to recombination of photogenerated electron–hole pairs within CdS layers. Spectral response measurements show photocurrent peaks for all TiO2/CdS films deposited by different method have red-shift to visible region and this result improves of successive composites between TiO2 and CdS. Finally using TiO2, and TiO2/CdS core-shell nano composite films prepared by different methods as photoelectrods device. This application was performed by using a standard three-electrode photoelectrocatalytic cell, the PEC measurements involves current-voltage (I-V) characteristics under darkness and under illumination (with UV-light source, and UV-Visible light source). The result for TiO2 films shows that all prepared films by different methods highly responses to UV-light source. And the higher response to UV-light was getting by using TiO2 film prepared by anodization technique with (HNO3+HF) electrolyte solution. For TiO2/CdS core-shell films we find that all films highly responses when illuminated of UV-Visible light source. This result is ensured the successful composite between TiO2 nanostructure and CdS NPs, because the film become absorbance the incident light located in visible region besides UV region. The higher response to UV- Visible light was getting by using TiO2 NRAs/CdS NPs film prepared by (CBD/CBD).
Synthesis of (Au) Nanoparticles with Porous Silicon for Sensor Application by Different Methods
By:Intisar Mohammed Khudhair   Supervised By: Prof. Dr. Uday Muhsin Nayef    year: 2017Abstract
????
In this work, porous silicon (PS) layer is prepared by electrochemical etching (ECE) approach using p-type silicon (100) orientation, with resistivity 1.5-5Ω.cm. The etching solution consists of HF (20%) and ethanol, at different current densities 5, 15 and 25 mA/cm2, and etching time of 15min. Morphology, structural and chemical properties studied by Atomic Force Microscopy(AFM), X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy respectevely. XRD investigation is appeared broad a diffraction peak when the size of crystal becomes inside nanometer . Reflectivity for bulk Si and PS layer prepared at 15 mA/cm2, etching time 15 min and HFc 20% is investigated. The photoluminescence PL for the sample is determined in air and different organic chemical vapor such as Ethanol, n-Hexane and Trichloroethylene and CO2 gas. Gold nanoparticles (AuNPs) have been prepared by laser ablation technique of gold target submerged in double distilled deionized water (DDDW) at different laser energies 160, 300, 460 and 600 mJ at 500 pulses number of pulse, using Nd:YAG laser at 1046 nm . AuNPs deposited on PS were prepared at 15 mA/cm2, with etching time 15 min and HFc 20%, by drop casting (5 drop). The Morphology and structural properties for AuNPs/PS is studied by AFM and XRD respectevely while, FTIR techniques confirmed the presence of Si-Au bond AuNPs were prepared by chemical reduction (seed-growth-methods) . The size of nanoparticle depends on the amount of seed added to growth solution. after that using solution by adding to solution etching where the solution consist of (HF+Ethanol+AuNPs) also PS prepare by electrochemical etching.the properties of samples AuNPs:PS such as The morphology characteristics investigated by AFM and the structural properties by using XRD, FTIR characterization techniques proved Si-Au bond. PL spectroscopy for AuNPs/PS and AuNPs:PS revealed that the intensity increase compare with PS layer alone where is depends on amount of AuNPs and effected by organic vapor chemical and CO2 gas where the PL intensity decreased (PL quenching) when exposed to this organic vapor and gas. [ii] PL quenching in the presence of organic vapor was found by decreasing radiative recombination of exciton that happen under the effect of the dielectric constant of the medium, and in CO2 PL is quenched because the absorption of CO2 increase the concentration of holes at surface. The injection of hole into valance band of porous silicon cause nonradiative decay of the excitation responsible for the extent of PS PL. Sensitivity of samples PS , AuNPs/PS and AuNPs:PS for CO2 gas study by the effect of the gas on electrical properties curve I-V found the current increased when exposed to gas because of the increase of the hole. The sensitivity of samples contained AuNPs is higher than samples of PS alone.
Detection of Some Dangerous Materials Via Raman Spectroscopy Technique
By: Haider Gheni Abdulzahra   Supervised By: Prof. Dr. Mohammad R. Mohammad & Dr. Naseer M. Hadi   year:2017Abstract
????
In this work a standoff Raman spectroscopy system has been designed to detect dangerous materials (Cyclotrimethylene-trinitramine C4, ammonium nitrate AN, trinitrotoluene TNT and urea nitrate UN) in dark laboratory at 4 m distance. The standoff Raman spectroscopy system employs frequency doubled Nd:YAG laser at 532 nm excitation with laser power of 250 mW and integration time of 2 s. The telescope was coupled to the Raman spectrometer using a fiber optics cable, and notch filter which is used to attenuate Rayleigh scattered light. The Raman scattered light is collected by a telescope and then transferred via fiber optics cable to the spectrometer and finally directed into CCD detector. In order to test standoff Raman spectroscopy system, it has been used to detect the spectra of toxic industrial compounds (TIC) such as acetone, toluene, and carbon tetrachloride. The standoff Raman results were compared with conventional Raman microscopy results using a bench top Bruker SENTERRA Raman instrument. The effect of integration time and laser power on Raman signal is studied. Standoff Raman detection of C4 substance at 4 m distance under partially illuminated environment was achieved and hence the effect of higher integration time was studied under the same condition. In order to test the capability of standoff Raman system of detecting explosives trace, detection of C4 and AN explosives have been achieved with limit of detection (LOD) of 20 µg for C4 and 40 µg for AN. Solid explosive samples were located on glass slides, aluminum plates and aluminum foil, while liquid samples were transferred into 3.5 mL quartz cuvette. Both types of samples were placed at a distance of 4 m from the telescope.
Preparation and Investigation Study on (CuO/H2O) Nanofluid for Improving the Performance of (PV/T) Hybrid System
By:Hadia Kadhim Judran   Supervised By:Assist. Prof. Dr. Sabah H. Sabeeh & Assist. Prof. Dr. Hashim A. Hussein    year:2016Abstract
????
Nanofluids are innovative and efficient class of heat transfer fluids. These fluids have unique thermal properties over the conventional fluids or base fluids such as water and ethylene glycol with long- term stability. The main goal of this study is synthesis of advanced coolant of nanofluid with enhanced thermal conductivity, high stability, low cost, different volume concentrations, and suitable for using it in cooling technique to improve the electrical and thermal performance of photovoltaic/thermal (PV/T) hybrid system. Therefore, CuO/deionized water nanofluid was synthesized via two-step technique. This technique is selected based on its good features, where it is economical and suitable for the production of oxide nanofluids in outsized scale. In first step, CuO nanopowder is prepared by a coupled chemical method using sol-gel/hydrothermal processes. The Sol-gel stage is carried out at room temperature in alkaline medium at pH=9. The product of first stage of coupled chemical method namely sol-gel process is treated hydrothermally through second stage in stainless steel autoclave at temperature of 160˚C for 3 hours. The products of two stages were characterized by using different techniques. The results of XRD technique proved that the product of sol-gel process (first-stage) is a nanocomposite of Cu(OH)2/SDS. High degree of crystallinity is obtained after hydrothermal treatment of Cu(OH)2/SDS. According to the XRD patterns, this nanocomposite material is totally converted to pure phase of polycrystalline copper oxide with monoclinic crystal structure by dehydration reaction during the second stage. The same results are confirmed by FT-IR measurements. Formation of two components is also confirmed by EDX quantitative analysis. FE-SEM measurements explained that the nanocomposite of Cu(OH)2/SDS has irregular layer-like structure, while CuO morphology is revealed a unique complex nanostructure. CuO nanopowder with prolate spheroid morphology is constructed from numerous numbers of very tiny nanoparticles as nano building units. The size range of these nano building units was (15-25nm). Based on the above results, growth mechanism of CuO nanopowder was demonstrated. The effect of Cu precursor molarity is studied in the range of (0.02-0.25M). The results showed that the impact of this parameter is related to size of prolate spheroid, purity of the yield, and quantity of the produced CuO nanopowder, but it has a slight impact on the average particle size of nano building units. II The optimum sample of CuO nanostructure was obtained by SDS concentration and Cu precursor molarity of 0.25M and 0.2M, respectively. FE-SEM analysis of optimum sample revealed that the size of complex nanostructure of CuO prolate spheroid was about (160-630nm) according to the measurement of major axis and about (125-325nm) according to the minor axis of prolate spheroid shape. The stability of CuO nanofluid was tested by two techniques; Zeta potential measurement and sedimentation or visual test. The results showed that the good stability of the optimum sample is devoted via surface electrical charge of (-48.29mV) and stability of dispersion behavior over more than 3 months. TEM and HRTEM results confirmed that the nano building units of CuO prolate spheroid have narrow distribution of nanoparticle sizes. The average particle size of (15.473nm) agreed very well with that calculated by structural information from XRD spectrum using Scherrer formula. In the second step, the mechanical approach was used to confirm the stability of CuO nanofluid with different volume concentrations. Thermophysical properties namely thermal conductivity, viscosity, specific heat capacity, and density were measured for CuO/deionized water with volume concentrations of 0.05, 0.1, 0.15, 0.2, and 0.25vol.%. The obtained results showed that all thermal properties of CuO nanofluid are improved with increased solid content of CuO nanopowder within the base fluid. The important property in heat transfer applications viz thermal conductivity revealed evident enhancement with increasing volume concentration of CuO nanofluid. The ratio of thermal conductivity enhancement (Knf %) is ranged from 4.49% to 32.945% for both lower volume concentration (i.e. 0.05 vol. %) and high volume concentration (i.e. 0.25 vol. %), respectively. The water cooling technique was designed for cooling the solar panel with surface area of about (1.81m2), which consisted of a heat exchanger and deionized water circulating through copper pipes with different mass flow rates of 1, 2, 3(L/min). The electrical performance of PV panel was recorded over a period of time from 7:30AM to 2:30PM as a function of solar irradiation intensity and temperature of PV panel surface. The results indicated that the electrical efficiency decreases from 9.1% to 2.7% when the PV temperature increased from 37.2˚C to 69˚C, respectively. By using deionized water as working fluid in PV/T system it was found that the optimum mass flow rate is 3(L/min) and the thermal gain is 3.9˚C at the end of period time of 2:30PM. Efficient cooling was III obtained by using CuO nanofluid as working fluid in PV/T hybrid system with different concentrations namely (0.05, 0.1, 0.15, 0.2, and 0.25vol. %) at mass flow rate of 3(L/min). The operating temperature of PV panel dropped significantly from 64.2˚C with deionized water cooling to 55˚C with cooling by CuO nanofluid at concentration ratio of 0.25vol.%. All the electrical characteristics of PV panel were linearly improved with increases in the volume concentrations ratios of CuO nanofluid. At optimum volume concentration of 0.25vol.%, the maximum enhancement in electrical efficiency of solar panel relative to that in case of water cooling about 47.65%. All the unique results are attributed to the high ratio of surface area to volume of CuO prolate spheroid within the base fluid. It is worth noting that up to now, preparation of pure phase with unique morphology as flower-like and prolate spheroid of CuO nanostructure without the need to the heat treatment after preparation process is very limited. Using the advanced and complex nanostructure for production of oxide nanofluid is a new contribution in the field of nanofluids synthesis. In addition, for the first time that CuO nanofluid is used in cooling system of PV panel. These aspects of this work are novel.
PREPARATION AND STUDY NANOMAGNETIC PROPERTIES OF Co-FERRITE
By:ZAHRAA SALAH AHMED   Supervised By: Asst. Prof. Dr. SABAH H.SABEEH   year:2016Abstract
????
In this work the Nano-magnetic materials (cobalt ferrite) with formula (CoFe2O4) as nano- powder was prepared from (Ferric Nitrite, Cobalt Nitrite and Citric Acid) by utilizing sol-gel auto combustion method, with different pH(3,5,7), then the powder were calcined at different temperatures(300,500,700)°C, and the samples sintered at different temperatures(1000,1100) °C. The structure, physical, mechanical, dielectric, and the magnetic properties of these samples were studied. The crystallite size (D) and the lattice factor (a) rise as the temperature rise, while X- ray density (ρx) decreases when the temperatures increase ,this word is compatible on samples with pH (3,7) ,but this behavior is different at pH (5). The images of (AFM) showed that a uniform structure without any valleys was observed and all the particles are aliened vertically due to the homogenously distribution of the ferrite particles. The dielectric constant of all samples which sintered at temperatures (1000, 1100) °C decreases with increasing frequency and also we show that the dielectric constant is highest at the frequency of (25) kHz and it lowering with the growing of hesitation in whole the specimens. The saturation magnetization (Ms) , Residual Magnetization (Mr), and Remanence Ratio(R) seem to increase with the increasing calcining and sintering temperatures ,at the same pH(7),while the coercivity (Hc) decreases with the decrease in the particle size, because there is a direct relationship between the coercive force and the particle size. The Relative permeability (µr) increases with increasing the calcining and sintering temperatures except the samples with pH (5). Finally, It is found that the samples with pH (7), at calcining temperature (700) °C, and at sintering temperature (1100)°C, have a good properties, which can be utilized in many applications.
EFFECTS OF DOPING, ANNEALING, AND DIFFERENT CHEMICAL METHODS ON THE CHARACTERISTIC OF NANO-STRUCTURED SnO2 THIN FILMS FOR GAS SENSOR APPLICATIONS
By:AMEL SAJIT SABER   Supervised By: Asst. Prof. Dr. SELMA MOHAMMED H.AL-JAWAD, Dr. ABDULHUSSAIN K. ELTTAYEF    year:2016Abstract
????
In this work nanostructured SnO2 thin films were prepared by using sol-gel (dip and spin) coating and chemical bath deposition techniques on glass substrate with (300 ± 20) nm thickness, which are simple and inexpensive techniques suitable for deposition of large area in different shapes. To indicate the best condition many parameters have been considered, namely annealing temperatures (300, 400, and 500ºC) at constant time of 60 minutes and Cu-doping concentration (2, 4, and 6) wt.%. Structural, optical and electrical properties of nanostructured SnO2 thin films were investigated and analyzed briefly at different conditions. Structure and surface morphology of nanostructured SnO2 films were characterized by using X-ray diffraction, atomic force microscope and scanning electron microscope measurements and transmission electron microscope. The optical properties of nanostructured SnO2 thin films were studied, such as transmittance, absorption coefficient, photoluminescence, and optical energy gap for different annealing temperatures and doping concentrations. The electrical properties of SnO2 thin films include D.C electrical conductivity and Hall effect which shows that the type of films is (n- type) semiconductors for different parameters, it is noted that the electrical conductivity increase with increase in annealing temperature and doping concentration for all films prepared. The gas-sensing SnO2 films fabricated via these techniques (dip, spin coating and chemical bath deposition ) for CO and NO2 gases in concentration of 50 ppm at R.T and 50 ºC were measured, the value of sensitivity is (23, 32) %, (28.5, 36.5) %, (32.83, 40.22) % respectively . The results show that the films prepared by CBD technique with 6% Cu doping. The undoped and doped tin dioxide films are a good sensor for CO and NO2 gas. The sensitivity proportional directly with the annealing temperature for limited range. In general the sensitivity increases by increasing the concentration of Cu. The results revealed that the procedure of film preparation plays an essential role in the design of sensors and getting high sensitivity.
Synthesis and Study the Structural and Physical Properties of Nano-BaTiO3
By:Mojahid Mohammed Najim   Supervised By:Asst.Prof.Dr.Sabah M. Ali Ridha    year:2013Abstract
????
At room temperature and normal pressure, Barium titanate (BaTiO3) and Barium Lanthanum titanate (BaLaTiO3) powders were prepared via a semi-oxalate method that uses barium oxalate and TiO2 precursors, instead of titanyl oxalate, in a solution pH adjusted around 5.5, the precursor this completely transforms into BaTiO3 at 920 oC. Nanometer size BaTiO3 crystallites are produced during this synthesis due to the lower calcination temperature. Nanoparticles of Barium titanate powder having a diameter of about 65 nm, was studied using several experimental techniques for the determination of the crystalline phases and purity of synthesized BaTiO3. The results of XRD ,FTIR and SEM spectroscopy analysis were contradictory with respect to the nature of the formed phase for the barium titanate nanocrystals. The first indicated the formation of a cubic phase and the second indicated that it was tetragonal. Thus, we use a combination of both (pseudo cubic and slightly tetragonal phases). The doping effects of La3+ on BaTiO3 powder ( Ba1-XLaXTiO3 , where ( x = 0.005, 0.015, 0.02, 0.025 ), where ( x ) was the volume ratio with respect to the structural were studied (XRD, FTIR and SEM spectroscopy analysis) . Owing to the replacement of Ba2+ of larger ionic radius with the dopant La3+ of smaller ionic, lattice parameter decreased slightly with increasing La content. The electric and dielectric properties for polymer/nanoceramic composites, polymer/BaTiO3 and polymer/Ba1-XLaXTiO3 where ( x = 0.005, 0.015, 0.02, 0.025 ), where ( x ) was the volume ratio and polymer(unsaturated polyester resin(UPE)), were studied in order to see the Interaction ferroelectric material(BT) and rare earth element (La) with the polymer component (UPE). Both the permittivity and energy loss of the encapsulated -BT or B1-XLXT composites showed lower values because the polarity of the hydroxyl groups on BT or B1-XLXT were suppressed physically by the UPE molecules. Therefore, polymer encapsulation of BT or B1-xLxT plays an important role in controlling the dielectric constants of the composites. We used the Bruggeman rule of Mixture to calculate eff ε which is the effective permittivity of the nanocomposite. Real dielectric constant decrease with increase (x) value for B1-xLxT, because the doping by La3+ brings more electrons into the system, increases the dielectric constant up to a critical doping level and the material changes from insulator to n-type semiconductor and back to insulator, means that the electronic contribution induced by La-doping can be charge compensated by B cation vacancy and/or reduction while creating oxygen vacancies and thus should be responsible for semi-conductivity.
Synthesis and Characterization of Graphene
By:Adi M. Abdul Hussein    Supervised By: Dr. Salam H. Ali & Dr. Hilal S. Wahab    year: 2013Abstract
????
Graphene, a single atomic layer of hexagonally arranged sp2–hybridized carbon atoms, with a thickness of only 0.34 nm, exhibits unique properties. The current interest in graphene can be attributed to three main reasons. Firstly, various forms of graphite, nanotubes, buckyballs and others can all be viewed as derivatives of graphene. Secondly, the scalability of graphene devices to nanodimensions makes it a promising candidate for applications in nano-devices. Thirdly, its electron transport properties are described by the Dirac equation which allows access to quantum electrodynamics in a simple condensed matter experiment. Among the different methods to produce graphene sheets by exfoliation of graphite, the electrochemical route has been very scarcely investigated. The electrochemical exfoliation of graphite represents a simple one-step method to produce graphene sheets in ionic liquid/water mixtures where hydroxyl and oxygen radicals produced by anodic oxidation of water start the oxidation of the edge planes of graphite, facilitating intercalation of an ions from the ionic liquid. The resulting graphene samples were characterized by, light optical microscopy, TEM, XRD, Raman spectroscopy, Ultraviolet and visible absorption spectroscopy. The XRD pattern of graphene film contains a sharp and intensive peak at 2θ = 26.1782°. The basal spacing of the graphite was increased from 3.35Å to 4.301 Å in the reduction of graphene oxide. This result indicates that the direct reaction of graphite particles with aqueous solution can be proposed as another route for the exfoliated graphite having excellent physical properties. Raman spectroscopy is employed to study various samples. Our calculations show that the, the lateral sizes La = 6.324nm, The intensity ratio IG/I2D of the product is ~1.59 and I(D)/I(G) ratio ~0.6957. As in the absorption spectrum has been calculated energy gap delegation was identical to our theoretical in Annex.
Studying Some Physical Properties Of Zn2xCu1-xIn1-xS2 thin Films Prepared by Chemical Spray Pyrolysis
By: Yousif Abid AL -Shaabani   Supervised By: Prof. Dr. Ala Alden Al-Naimi & Assist . Prof.Dr.Hamid Al-Jumaili    year:2009Abstract
????
Thin films of Zn2xCu1-xIn1-xS2 (ZCIS) with various values of X ={0,0.1,0.2,….and 1} , have been prepared by spray pyrolysis on glass slides (25mm ×25mm) substrate at temperature (Ts) of 350 ±10oC . The thickness of thin films are 400 ±20nm . The obtained results of x-ray diffraction (XRD) structure analysis was polycrystalline for all values of X. When an amount of Zn atoms added to the compound a new phase structure was formed which is a mixture of chalcopyrite and zinc blende . This new phase continues until x=0.5 , after that it shifted toward zinc blend structure . The morphology of the prepared thin film surface showed a superstructure when Zn was added and gives more roughness . The optical characteristics of Zn2xCu1-xIn1-xS2 thin films have been investigated by UV – VIS spectrophotometer in the wavelength range (300 -1000nm ) . The films have a direct allow electronic transition with optical energy gap ( Eg ) values varied between 1.58- 3.5eV depending on X value. Therefore the ZCIS films are promising in thin film solar cell applications . The maximum value of the refractive index (n) for all thin films is obtained to be 2.7 in the visible region . The dependence of extinction coefficient (K ) value on the film structure was found. So it gives two minimum value at two wave lengths , this means there are different absorption mechanisms . The maximum value of real dielectric constant is about 7 for all values of X . But the value of imaginary part ( Є2 ) was changed with X value. Also the tail width ( Et ) in the energy band is calculated to give a maximum value at X =0 , which equal 0.45 eV and decreased to 0.18 eV , this means that Zn gives good crystallinity and different structure than CuInS2 . The electrical properties of Zn2xCu1-xIn1-xS2 thin films were investigated . Hall experiment results an evidence of a p-type conductivity from X =0 to X =0.8 and n-type conductivity for X =0.9 and X =1 . The D.C conductivity ( σ D.C) was increased to a discrete limit temperature and then it becomes nearly constant with temperature . The films appeared to have one or more activation energy ( Ea) depending on X values . This means that there are many mechanisms the conductivity . The I-V characteristics at dark and illumination of ZCIS thin films were investigated , it was found that Id and Iph increase with (V),and the values of Iph were greater than Id for all films . Also Id and Iph found to depend on X value . The variation of Id and Iph with wave length ( λ ) gives Iph greater than Id for all thin films and the maximum value of Iph was at X=0.5 . The maximum photosensitivity occurs in the wave length between (500-580) nm . The ZCIS thin films are photosensitivity with laser He-Ne and semiconductor laser.
Modeling of Organic Solar Cells Parameters for Efficient Performance
By:Wisam Abdullah Latif   Supervised By: Assist. Prof. Dr. Dayah. N. Raouf   year: 2009Abstract
????
Although the efficiency of organic solar cells is not yet high enough to be competitive with inorganic solar cells, but it has certainly increased significantly to reach about 5% at present. To gain better insight into the interplay of the various critical parameters that influence the performance of organic solar cells, we have built up a numerical model for the electrical characteristics of bulk heterojunction (BHJ) solar cells relating their performance to basic physics and material properties such as charge carrier mobilities. This model is based on the metal-insulator-metal (MIM) picture, as it describes the generation and transport processes in the BHJ as if occurring in one virtual semiconductor. Drift and diffusion of charge carriers, the effect of charge density on the electric field, bimolecular recombination, and a temperature- and field-dependent generation mechanism of free charges are incorporated. By using values as close as possible to published experimental ones, the experimental current-voltage characteristics are regained. We demonstrate, using our model, that the balance between the carrier losses by extraction and recombination leads to a distinct optimum in the carrier mobility with regard to the efficiency of organic solar cells. For low mobilities recombination losses limit the performance, whereas the efficient extraction at high mobilities leads to a reduction of the open-circuit voltage (V_oc) and consequently drop in the efficiency. Space charge limitations in organic solar cells have been studied, on bases of which an analytical relation for the conversion efficiency is predicted. Numerical modeling on suitable BHJ system have confirmed that the intensity dependence of the short circuit current (J_sc) is governed by space charge rather than by bimolecular recombination alone. Calculations based on the model presented in this work confirm that decreasing polymer's band gap, which leads to an increase of the amount of photons absorbed by the film, would indeed increase the performance of solar cells. However, we demonstrated that combining this effect with the effect of minimizing the energy loss in the electron transfer from the polymer to the acceptor phase would enhance the performance even more. We concluded that the efficiency of BHJ solar cells can reach a value of more than 10%, provided that; the band gap of the polymer is between 1.9 and 2.0 eV, balanced carrier transport(μ_p≅μ_n ), and an active layer thickness is between 150-200 nm.
Crystal Structure and Morphology of Nano Ba(Zr,Ti)O3 Prepared Using Hydrothermal Method
By:Mukhlis M. Ismail   Supervised By: Dr. Sabah M. Ali & Dr. Ziyad S. Ahmed    year: 2009Abstract
????
Nanocrystalline Barium Zirconate Titanate BaZrxTi1-xO3 (x=0 (BaTiO3 or BT), x=0.001 (BZT1), x=0.008 (BZT2), x=0.027 (BZT3), x=0.064 (BZT4) and x=0.125 (BZT5)) were prepared hydrothermally using TiCl4, ZrOCl2.8H2O, Ba(OH)2.8H2O and NH4OH as starting materials at 150oC for 2h. The structure of the prepared nanocrystalline BT and BZT powders were a metastable cubic perovskite according to XRD, DSC and HRTEM analysis, while FT Raman spectra showed that BT and BZT with Zr content less than 0.8% have a tetragonal structure. The volume of unit cell of the prepared powders were 64.96, 65.013, 65.086, 65.3, 65.59Å3, and 66.28 for BT, BZT1, BZT2, BZT3, BZT4 and BZT5, respectively while it shrinked after annealing powders at 500 and 700oC and became close to standard at 1000oC. Hydroxyl and carbonate groups were observed in all prepared powders that showed in FTIR spectroscopy as a vibrational band at 3200-3600cm-1 and 1447cm-1, respectively. Most of hydroxyl groups which were observed in TG analysis refer to surface absorbed water, therefore the amount of hydroxyl groups which was shown in TG (1.725%) was greater than that shown in XRF (0.3638%) results. The crystallite size of BT powders have increased with the increase of annealing temperature from 19nm at room temperature to 70nm at 1000oC, while for BZT this range reduces with the increased Zr content. According to FTIR spectroscopy at different annealing temperatures, the hydroxyl groups were expelled less than 600oC while carbonate groups needed more than 700oC. The prepared powders have converted to a tetragonal phase after annealing at 700oC for BT and more than 700oC for BZT1 and BZT2 only. Contrast variations across particles were observed by TEM images which indicated the presence of high strain inside the BZT lattice. TEM image showed a dendrites shape for BT and showed spherical shape for BZT. Well- crystallized, and single crystal nature was shown in all powders as revealed by a SAED and HRTEM analyses. These analyses showed also that the surrounding edges of the particle are very smooth with no surface steps. For prepared BT powders, small nucleated islands with thickness about 5nm were observed at the edge of the particle.
Characteristics of Polymer Composite Materials Waveguide
By:Latef Mohamed Ali   Supervised By:Dr. Mahdi Hassan Suhail & Dr. Nabeil Ibrahim Fawaz    year:2009Abstract
????
Finding suitable polymer composite materials for the transmitting of X-band frequencies in the range 8-12 GHz, are useful for communications. In this work, we describe the simulation characterization of composite waveguide components, PS/Alumina , ABS /Barium titanate ,Barium titanate/ EPDM and zirconium tin titanate / epoxy. The detection limit of a complete numerical solution of Helmholtz equation for composite waveguide has been determined. A computer program was used to calculate the propagation constant and field patterns of the modes in a waveguides. The effect of the slab thickness and applied frequencies on the propagation characteristics and the number of the modes were investigated. The electric fields within the dielectric slab waveguide, were used to calculate the transmission coefficient of the dominant and fundamental modes. This was implemented in MATLAB program, and the numerical values for the modes of propagation were obtained. A good correspondence between number the of modes and the cut off thickness was found. The transmission of microwave depend on the slab thickness and the frequencies was investigated, and the calculation of the transmission coefficients was obtained. It has been found that varying the refractive index and the frequency has a much large effect on transmittance. It should be mentioned, that the normal-incident transmission coefficients have been calculated in this work. The transmission for the samples under the study were varied from zero to a maximum value (100% ) . This study demonstrates the feasibility of obtaining composite waveguide as a low-loss, single-mode transmission and useful for designing a waveguide filter. Ultralow-loss lines are possible by reducing the thickness of the slab of the samples.
Preparation and Studying Some Physical Properties of Polycrystalline PbI2 Films
By:Shatha Shammon Batros Jamil   Supervised By: Dr.Ali M. Mousa. Alzuhery   year: 2008Abstract
????
Lead iodide is one of the most important materials which is used in x- ray detectors. It is prepared from the chemical reaction of (0.01M) Pb(NO3)2 with (0.05M) KI . Some of tests have been carried out to determine the presence of other materials in lead iodide. Thick films were deposited from lead iodide on glass by solution method. This method has a low cost and fast preparation which is produce a large area with appropriate designed thickness without need to complex techniques or assistant agents in a comparison with other methods. The present study of deposited film focused on structural, electrical and optical properties. Also this research studies the effect of doping on the physical properties of lead iodide with different dopants at different weights, annealing temperatures, where it used with dopant material which are Barium nitrate and Holmium oxide with (0.002gm,0.005gm,0.007gm) weight and in annealing temperature from 50oC to 200oC. The x-ray diffraction diagram shows polycrystalline hexagonal structure with four peaks which correspond to (001),(002),(003),(004) reflection planes. It is found that peaks intensity change with doping and annealing processes, Some structural properties such as grain size, micro strain ,shape factor, number of layers as a function of dopant weights and annealing temperatures were calculated. The electrical measurement shows that the electrical conductivity of lead iodide films is (0.99*10-9 Ω-1.cm-1) at dark , and (1.34*10-7 Ω-1cm-1) under light. The ratio of light conductivity to dark conductivity =135 at room temperature and at 100oC for one hour it increases to reach 331.08, then decreases sharply with increasing dopant weight and annealing temperature to reach 150 oC to 164 and 82.66 for both Ba , Ho respectively .The activation energy was calculated and its values between 0.0493 to 1.125 eV. The Hall measurements show the influence of compensation effect of dopant weight and annealing temperature and it was found that Barium of great effect in compensate than Holmium . The optical data were analyzed and interpreted in terms of direct electrical transitions. Transmission spectrum of undoped lead iodide exhibits a sharp increment starting from around (520nm) and becomes sharper with doping and annealing processes. It is found that absorption coefficient has a high values. It was observed that pure lead iodide has a wide direct band gap of values (2.305eV), This energy gap is affected by doping and annealing. The higher spectral response for PbI2 is at wavelength between 480-500nm.
Preparation and characterization of some physical properties for Copper and Copper alloys –SiC Composites
By:Samir Bahjet younis   Supervised By:Dr. Ziyad S. Ahamed & Dr.Ali M. Mousa    year:2009Abstract
????
Copper powder and its alloys reinforced with SiCp ( 0- 10 wt%) were prepared using powder Metallurgy technique for a composite in which aluminum powder of ( 2 wt%) was added for improving wettability of the ceramic phase. . The mixture were blended with a ball mill for one hour to ensure a homogenous distribution on the composite .Green compacts pressed at (350MPa) using stainless steel die of (11) mm radius are then sintered at (900 °C) for two hours in an electric furnace, with argon atmosphere .Physical measurements like density, porosity, XRF, XRD, and Optical microscopy have been preformed . The microstructure of the composite presented a uniform distribution of SiCp in the matrix and good interfacial integrity. The density found to be decreased gradually with SiC content in three types (green, sintered and apparent density) especially from 4 wt% and above . Mechanical properties of the composites are investigated ,like Vicker’s hardness, compressive strength, and a dry sliding wear at constant speed ,under applied loads (5,10,15)N for two periods (10,20)min tests are then conducted for the sintered samples. The hardness , compressive strength of the composites has been increased with increasing SiC content, but at the cost of ductility. Wear performance will be enhanced with SiC content, compared with pure Cu alloys. This is due to the reinforcing SiC particles being effective to reduce the extent of wear deformation in the subsurface region during sliding. Finally electrical tests are prepared to measure electrical resistivity.It was found that more SiC content mean more electrical resistivity ,however it remains at fairly high level compared with the pure Cu alloys.
Deposition and Study Some Physical Properties of PbI2 Thick Films
By:Randa Kamel Hussain ALJubori   Supervised By:Assistant Proff.Dr. Ali M. M Alzuhery & Assistant Proff.Dr. Najat J. Saleh    year: 2006Abstract
????
In this work, simple and low cost method is adopted to prepare thick layers of lead iodide (PbI2); solution deposition method provides a chance to deposit large area with appropriate designed thickness, not needing complex techniques or assistance agents. Layers prepared by this method have the same properties of layers deposited in other methods. This work studies the influence of doping and annealing conditions (temperature and time) on the properties of lead iodide; three types of dopants were used with three different weights (0.0025, 0.005 and 0.0075gm), namely: AgNO3, CdSO4 and CaCl2. While annealing influence is studied in range (75-200 0C) for 1hour and 2 hours. The present study focused on the structural, electrical and optical properties of films prepared under different conditions. The experimental results of XRD showed polycrystalline hexagonal structure with four main peaks which correspond to (001), (101), (003), and (004) at d=6.807, 3.505, 2.304 and 1.713 respectively. It is found that the peak intensity changed with doping and annealing, and some shifts of peak positions accompanied the doping and annealing. The electrical measurements showed the electrical conductivity of PbI2 was (4.163x10-14 S.cm-1) and it increased when the film is illuminated by white light to (1.701x10-12 S.cm-1). The best ratio of photoconductivity to dark conductivity ( ) obtained from annealed undoped PbI2 at 200 0C for 2 hour (68.34). This ratio sharply decreased by doping, where the dark current is increased with increasing doping weight and with increasing annealing temperature; Ag and Cd dopants cause increment in dark conductivity ( ) 76.8 and 66.13 times when doped by (0.005gm) respectively. While adding the same amount of Ca caused dramatic decrease in dark conductivity with 6.7 times. Also the activation energies determined for different samples and their values changed within the range (0.0307 – 1.115 eV). According to linearity properties, it is found at voltage (> 350 V) and power (> 15x10-5 W) it is close to the superlinear behavior, while the behavior is more or less linear in the voltages (250-300V). For lower applied voltage (< 200 V) the behavior is sublinear. The linearity of PbI2 is enhanced by doping, where the photocurrent is superlinear at (> 250 V) and for incident power > 0.3 mW, that is clear in 0.0025gm of Ag, 0.005gm Cd and 0.0075 gm Ca doping case. The optical data were analyzed and interpreted in term of direct electronic transitions. Transmission spectrum of undoped lead iodide exhibit a sharp increment start around (~520 nm) and it becomes sharper with doping, and shifts occur by doping or by annealing. It was observed that lead iodide has wide direct band gap (2.36 eV), the energy gap is affected by doping and annealing; it decreased as the doping weight increased and as annealing temperature increased.
Study of Some Physical Properties of CdS Films Prepared by Chemical Bath Deposition
By:Selma Mohammed. H. Al-Jawad   Supervised By:Dr. Ali M. Mousa & Dr. Adawiya J. Haider    year:2006Abstract
????
In this work CdS films were prepared by using chemical bath deposition, which is a simple and inexpensive technique suitable for large deposition area. Many growth parameters have been considered in this work to specify the optimum condition, namely (temperature of solution, pH, thiourea ion concentration and deposition time). Structure, optical and electrical properties of CdS films are investigated and analyzed extensively with respect to growth conditions. Annealing in air at different temperatures (300, 350, 400, 450, and 500) at constant time of (30 min), also for different times (15, 30, 45, 60, and 90) min at constant temperature (300CO) is achieved. X-Ray analysis has confirmed the formation of cadmium oxide (CdO) with slight increase in grain size, shift towards lower scattering angle due to relaxation in the tensile strain for deposition films, and structure change from cubic and hexagonal to the hexagonal. From electrical properties, significant increase in electrical conductivity appeared in samples annealed at (300 ) for 60 min, and at (350 ) for 30 min. High quality films are achieved by adding chelating agent EDTA and buffer solution of to the deposition bath, leading to increase in transmission for films and increasing ratio of photo current to dark current. A high value of = using EDTA obtained, conforms the use of CdS as a photoconductive detector with high spectral responsivity of 0.257 A/W at 520 nm. Nanocrystalline CdS have been deposited, the band gap changes from 2.58 eV to 2.8 eV as compared to the bulk CdS band gap of 2.42 eV , as a result of quantum confinement. Nano crystalline CdS is deposited on the p- type silicon formation heterojunction, with high spectral responsivity of 0.41 A/W, quantum efficiency 90% , and specific detectivity 2.9 * cm . Also the shape of the spectrum of nano CdS/p-Si is extended into the blue region, due to widening of the window band gap. In addition, bulk CdS films deposited on p-type silicon, show increase in the spectral responsivity for the detector after annealing and also after adding chelating agent EDTA compared to the as- deposited films. High performance rectifying contact with a rectification ratio exceeding 20 is obtained by depositing nano crystalline CdS on p-type silicon. Annealing causes enhancement in the rectification ratio due to relaxation in the film structure.
Preparation and Investigation of Conductivity and Dielectric Behavior of Some Ferri-Ferro Composites
By: Inaam Mohammed Abdul Majeed Al-Obaidi   Supervised By:Dr. Khalid T. Mahdi & Dr. Sabah M. A.Ridha    year: 2005Abstract
????
Magnetoelectric composites are prepared in this work; these are containing ferrimagnetic and ferroelectric phases. The magnetoelectric effect couples two field effects. The first, magnetization due to application of electric field and the second, electric polarization due to the application of magnetic field. These materials are applied in the field of electronic technology. In this work, the ferroelectric phases BaTiO3 and SrTiO3 were prepared, while the ferrimagnetic-preparing phase was NiFe2O4, by using the conventional ceramic method. All formation phases were identified by X-ray diffraction pattern. In addition, particle size was measure for all the prepared phases. Dry pressing forming technique has been used to prepare three different ceramic compacts systems of (BaTiO3-NiFe2O4), (BaTiO3-Fe2O3), and (SrTiO3-Fe2O3) with different molar ratios. All compacts were fire at 1200 C˚ for 12 hrs, then all phases identified by using XRD. After grinding, polishing and etching, the microstructure of the samples were studied by using optical microscope. Results showed that, the increment in the bulk density with the content of BaTiO3 for (BaTiO3-NiFe2O4) system reaches at about 4.47 gm/cm3 with molar ratio of 75% BaTiO3 content. While for (BaTiO3-Fe2O3), the bulk density reaches about 4.88 gm/cm3 with molar ratio 75% Fe2O3, but for (SrTiO3-Fe2O3), the bulk density is 4.1 gm/cm3 with molar ratio 75% Fe2O3. Electrical investigations were carried out for all the prepared samples in the range of frequency of about (100 Hz-5MHz).The ac electrical conductivity increases while the dielectric constant and dielectric loss factor decrease as frequency applied electric field increases, then it reaches a constant value for all composites. It was observe the value of dielectric constant for the first system (BaTiO3-NiFe2O4) is (30-660). However, the dielectric constant in the range of (30-580) for the second system (BaTiO3-Fe2O3), while for the third system (SrTiO3-Fe2O3) in the range of about (40-730). The loss factor productions in the same range of frequency as mentioned above, for the first system acquire in the range (0.01-0.45). However, for the second system it was in the range (0.1-1.9). Finally, in the third system was in the range (0.01-1). The dc resistivity increases with increasing the temperature ranged between (300-500) K for all the samples. Finally, the variation in the thermoelectric power with temperature for the (BaTiO3-NiFe2O4) system decreases with increasing the temperature up to about 400 K˚ and remains constant for above that temperature, the majority of the charge carriers over the whole ranges of temperature are holes. However, for (BaTiO3-Fe2O3) and (SrTiO3-Fe2O3) systems, at lower temperature all the sample show positive seebeck coefficients and there is p-n transition observed in all composites at higher temperature.
Analytical Study for Ceramic – Metal Coatings Prepared By Plasma Spraying Technique
By:Ihsan Ali Abdul Kareem   Supervised By:Dr. Ala Alden Alnaimi & Dr. Khalid Taha Alrasoul    year:2005Abstract
????
The top coat 24MgO-ZrO2 and Al2O3 thermal barrier composite ceramic was sprayed using atmospheric plasma spraying technique on a NiCrAlY layer as the bond coat layer, deposited on a stainless steel 304 substrate. Fully stabilized zirconia base powder with three mixtures of 24MgO-ZrO2 and Al2O3 powders were used, with (80/20, 60/40, and 40/60) wt% (24MgO-ZrO2)/Al2O3 powder mixtures ratio. The visualization of the coating topography showed a variation and enhancement in porosity of the coating surface with the increased alumina ratio in the composite. The measured apparent porosity was 7.75% for the highest alumina content coatings. The adhesion strength of the coating was ~ 21.4 MPa. measured using test method (ASTM C633-01). The composite coatings also exhibited increasing in measured hardness values (3412-5387 MPa.) as a function of alumina content By subjecting the coatings to different heat treatment conditions (500-1000˚C) the thickness of the coatings decreased by (50, 16, 42 and 58%) for coatings produced from 24MgO-ZrO2, 80/20, 60/40, 40/60 wt% premixed ZrO2/Al2O3 powders respectively. The microstructure features were investigated via X-Ray diffraction. The analysis showed that the major coating phase was cubic zirconia with the minor magnesia phase; the alumina phase was identified as γ-alumina. The XRD pattern showed broadening diffraction lines with some shift in maximum peak position, due to small crystallite size and lattice micro-strain of zirconia. Various methods for size evaluations have been proposed for extraction of the size information in coating material. The crystallite size was calculated using four methods of crystallite size evaluation; Scherrer formula, FW1/5/4M, Integral Breadth and Fourier analysis methods. The convolution model was utilized with Gaussian, Lorentzian and Pearson7 functions. Due to overlapped diffraction lines, this study was confined to single line analysis with the focus being on the (111) reflection of cubic zirconia. The size analysis results showed that heat treatment promotes crystallite growth. The comparison showed that size results are dependent upon the character of diffraction peak shapes. One of the major objectives of this project is to study the thermal conductivity of the prepared coatings. Thermal conductivity measurements of the prepared coatings showed increasing values as the alumina ratio in the premixed powders increases, where the coatings produced from 20wt% alumina, showed an increase in the overall thermal conductivity of the composite coating by as much as a factor of two. Which are due to the anisotropic composite coating combined with the large difference in thermal conductivity between ZrO2 and Al2O3 will alter the thermal behavior of the coating.
