Materials Science Forum Vol. 1039

Abstract: Methyl ammonium lead iodide CH₃NH₃PbI₃ Perovskite was synthesized by a new method mixing between one and two steps, in addition, the ethanol solvent was used to dissolve CH₃NH₃I and compared with isopropanol solvent. The characterizations of synthesized perovskite samples included the structural properties, morphological characteristics and optical properties. The intensity and orientation in X-ray diffraction patterns appear clearly in ethanol solvent while disappearing at a peak at 12^o due to the speed reaction of perovskite in this solvent. Additionally, the ethanol solvent increasing the grain size of perovskite which homogeneity of the surface morphology. the ethanol solvent cause a decrease in the wavelength of absorbance edge in addition to an increase in the energy bandgap value. Keywords: Ethanol Solvent, Perovskite, Photovoltaic Technologies, X-ray diffraction.

Abstract: Sulphated zirconia (SZ) is one of the most important solid acid catalysts was synthesize at different operating conditions,different calcination temperature and sulfonating time has been used. The prepared catalyst was distinguished by X-ray Diffraction (XRD), particle size and morphology of catalyst were checked by atomic force microscopy (AFM) and scanning electron microscopy (SEM) respectively, in addition to analysis by (DTA) Differential thermally and Energy Dispersive X-Ray (EDX). Finally, the N2 adsorption-desorption was used to measure the surface area (BET) and pore volume. High degree of tetragonal crystallinity was obtained 90 %, and surface area of 169 m²/g and pore volume of 0.39 cm³g^-1 at 600°C calcination temperature for 3 hrs and 6 hrs time of impregnation in H₂SO₄. nanoparticle size of sulphated zirconia was produced with an average of 73.48 nm.

Abstract: Preparation of nanocomposite ( CO₃O₅,Fe₂O3: Sn ) was chemically held from its raw materials as a first step of this research in order to manufacture photoelectrode , this nanocomposite was deposited on substrate glass using spraying technique and heat treatment by Nd: YAG laser pulse (LPD) . Experiments were conducted to study the surface topography of the nanocompound by (AFM) to determine the roughness of the prepared electrode, In addition, the structure characteristics were studied using the x-ray diffraction (XRD) to determine the main phase. The second step of this research was designing a glass electrolysis cell containing our nanoelectrode and producing hydrogen. Finally the electrochemical parameters of the designed cell were studied Key words: nanocomposite (CO₃O₅,Fe₂O₃:Sn), Nd: YAG laser pulse (LPD) , Photoelectrodes; atomic force microscope.

Abstract: By using the spray pyrolysis technique, un-doped and Fluorine highly doped iron oxide Fe2O3 thin films were deposited on a glass substrate at a temperature of 380 oC and at different dopant concentrations (10, 15, and 20) %. The crystal structure and optical characterization of the deposited thin film were performed by x-ray diffraction and UV-Vis spectrophotometer. The XRD results revealed that the presence of a very wide peak in-between (15-35) o angles, this gives evidence that un-doped and F-doped Fe2O3 thin films have very low crystallinity and amorphous structures. The optical absorbance edge was shifted towards short wavelengths (blue shift) and the absorbance was reduced with the increase of Fluorine dopant content. The optical constants such as absorption, extinction coefficients, and the optical conductivity of the deposition films were investigated as a function of dopant content. The optical energy band gap of un-doped and Fe2O3:F thin films was found to be increased when increasing of the Fluorine content and exhibited a direct allowed energy gap (Eg) from (2.55 to 2.7) eV which can related to the Burstein-Moss effect.

Abstract: The existing investigation explains the consequence of irradiation of violet laser on the structure properties of MawsoniteCu₆Fe₂SnS₈ [CFTS] thin films. The film was equipped by the utilization of semi-computerized spray pyrolysis technique (SCSPT), it is the first time that this technique is used in the preparation and irradiation using a laser. when the received films were processed by continuous red laser (700 nm) with power (>1000mW) for different laser irradiation time using different number of times a laser scan (0, 6, 9, 12, 15 and 18 times) with total irradiation time (0,30,45,60,75,90 min) respectively at room temperature.. The XRD diffraction gave polycrystalline nature with tetragonal crystal system.The result was that the structure properties of MawsoniteCu₆Fe₂SnS₈thin films affected by laser irradiation where the XRD measurement the result was the grain size and stress values that decrease with increasing irradiation time, whereas the values of intensity , FWHM and d-spacing for the largest peak increase with a slight increase with the increase in the irradiation time and slight increase in growth of some peaks with increasing irradiation time.. While not affected EDX and FTIR measurements by laser irradiation, the result was the same for all samples.As for AFM measurement showed that the surface roughness, root mean square and average diameter values that decrease with increasing irradiation time. Note from SEM measurement that the surface topography affected with different time of irradiation red laser. This result due to laser irradiation worked like annealing temperature to enhance the crystallization of the deposited films. As the results showed that the laser irradiation method has a clear change in the structure properties with less time and energy than the traditional annealing methods which is the aim of this study. Keywords: red laser irradiation, semi-computerized spray technique, Structure properties of Mawsonite, Cu₆Fe₂S₈Sn.

Abstract: In present work, the structure, absorption and energy gap of films prepared from biodegradable polymer doped ZrO₂-SiC NPs for UV-shielding, biomedical fields and optoelectronics approaches were investigated. The nanocomposites films were fabricated by casting method. The absorption spectra was measured in range (200-800) nm. Results indicated to enhance in absorption and energy gap of biopolymer by adding of ZrO₂-SiC NPs ratios, this behavior make it suitable for various applications like antibacterial films, anti-UV light, diodes, solar cell, transistors and other fields. Keywords: biodegradable polymer, UV-shielding, absorption, energy gap, ZrO₂.

Abstract: In this paper, a theoretical model is used to investigate and evaluate the electronic transfer rate by using Au metal contact with 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline, known as BCP. Electron transfer process is a necessary in variety electronic devices. The electron transfer rate investigates and calculates for Au/BCP interface due to transition energy, Fermi energy, ionization energy and strength coupling to calculate results in a wide solvent media. In this work, the Au metal is used a donor state with BCP molecule as acceptor to study the electron transfer process with changing thirteen solvents media. The results show that electron transfer parameters of the Au/BCP system have been strong dependent on transition energy. It's given acceptable rate in room temperature with barrier ranging 1.169, 1.091, 1.081, 1.086 and 1.064 eV for Diethyl ether, Ethyl, Tetrahydrofuran (THF), Acetic acid and 1,2-Dimethoxyethane as result to have low transition energy compare with 0.946, 0.940, 0.967, 0.951, 0.970 and 0.977 eV for Methanol, Water, Acetone, Ethanol, Acetonitrile and 2,2,2-Trifluoroethanol because have large transition energy.The Au/BCP device has large electron transfer rate with water and Methanol in range 19.328 × 10^-9 to 15.205 × 10^-9 (cm⁴/ sec) compare with low electron transfer rate with Diethyl and Ethyl acetate in range 0.006 × 10^-9 to 0.091 × 10^-9 (cm⁴/ sec). Moreover, the devices that are employing Au in contact with BCP show higher electronic transfer rate with less polarity solvent.

Abstract: This study investigated and calculated the fill factor and efficiency of N719 and D149 organic dyes in titanium dioxide (TiO₂) solar cell systems using a current equation that we derived using a quantum transition-state theory (TST). The theory of charge transfer reactions was used to investigate the electronic current to enhance both the fill factor and efficiency of both N719/ and D149/TiO₂ solar cell systems. The current calculated for Di-terabtylammoniumcis-bis (isthiocyanato) bis (2,2-bipyridyl-4,4dicarboxylato) ruthenicyanatoum (II)(N719) and 5-[[4-[4-(2,2-Diphenylethenyl) phenyl]-1,2,3-3a,4,8b-hexahydrocyclopent [b] indol-7-yl] methylene]-2-(3-ethyl-4-oxo-2-thioxo-5-thiazolidinylidene)-4-oxo-3-thiazolidineacetic acid indicated that the molecules of D149, an indoline-based dye, have to be in contact with the semiconductor due to the quantum donor-acceptor scenario model. The efficiency of N719/and D149/TiO₂ solar cells were significantly affected due to transition energy, which is caused by the mechanisms of the charge transfer process. Solvents; such as trifluoroethanol (C₂H₃F₃O), propanol (C3H8O), ethanol (C₂H₅OH), and acetonitrile (C2H3N); were used to determine the current, fill factor, and efficiency. Coefficients of charge transfer; such as transition energy, barrier, driving force energy, current, power-conversion efficiency, fill factor (FF), and efficiency; were evaluated theoretically. The current of the N719/ system with acetonitrile and ethanol solvents was higher than current of the N719/ system with trifluoroethanol and propanol solvents. While the current of the D149/ system with trifluoroethanol and propanol solvents was higher than current of the D149/ system with acetonitrile and ethanol solvents. The current and transition energy efficiencies of both systems varied. devices were found to have the best power conversion efficiency and low transition energies while the power conversion efficiency was large for devices with sizeable current density and activity with lower transition energies. Keywords: Fill Factor, Efficiency, Molecule/Semiconductor, Solar Cells.

Abstract: In this research, Zn_1-xCd_xSe alloys (x from 0 to 1) were synthesized by solid-state microwave (SSM) method of producing thermally evaporated thin films. The cubic structure and the elemental ratios of the films were studied using X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The optical characterizations of the as-deposited film in terms of the energy band gap (Eg), photoluminescence (PL), and Raman shift spectra were conducted at the room temperature. The Eg values for the thin films from ZnSe to CdSe were 3.4 to 1.7 eV, respectively. The PL orange emission for ZnSe thin film at 565 nm, whereas 590 nm in the yellow region for CdSe thin film. From Raman shift spectra, the two longitudinal-optical phonon modes (1LO and 2LO) at 240, and 490 cm^-1 are assigned for the ZnSe and CdSe thin films.

Abstract: In the current study, the density function theory (DFT) is used to investigate the chemical adsorption strength of NO₂ gas molecule. The relaxation structure, molecular orbital energy, energy gap and adsorption energy are calculated at ground state. The time dependent DFT (TD-DFT) used to simulate excitation provides UV-Visible spectrum. There was a perpendicular geometrical orientation of the gas molecule around the surface and an adsorption distance of 2.58 Å. The adsorption distance shows the chemical reaction between the gas molecule and the surface. The result of adsorption energy indicates that the gas molecule that closed to the surface has high interaction and it decreases gradually when gas molecule goes further from the graphene nano-ribbon surface. The UV-Visible measurement indicates that the system interaction with gas molecule has red shifting in electromagnetic radiation. The final result concludes that graphene nano-ribbon has high reactivity for NO₂ gas molecule. The theoretical calculations provide the ability to design optical sensor which has useful applications in an environmental monitoring.