Journal of Kufa - physics

In this work, perovskite compounds were prepared and studied by using chemical methods for methyl ammonium halide MABr and lead halide PbI2. The main objective of the study is to successfully prepare new types of perovskites using the one-step method by changing the weight ratios of lead halide PbI2 in a fixed weight ratio of methyl ammonium bromide MABr, where they were classified into samples P1 which represents MABr/PbI2 weight ratios (0.22:0.39)g, P4 which represents MABr/PbI2 weight ratios (0.22:0.59)g and P7 which represents MABr/PbI2 weight ratios (0.22:0.79)g and the impact of this change was studied. High crystallinity was obtained in the crystal structure of the P4 sample after increasing the weight ratio of lead halide from 0.39 g to 0.59 g. Then the crystallization decreased and the crystal structure changed after increasing the weight ratio from 0.59 g to 0.79 g in the sample P7. The increase in PbI2 weight from 0.39 g to 0.59 g and 0.79 g affected the absorption edge and shifted widely towards long wavelengths (red shift) from 625 nm to 691 nm and 805 nm. The energy band gap changed from 1.98 eV to 1.79 eV and to 1.53 eV. The study showed that the surface morphology of these samples, where a sample with a homogeneous film with a high density was obtained, resulted from an increase in the weight of lead halide from 0.39 g to 0.59 g and with small Nano-diameters of 34.25 nm for the P4 sample. After increasing the weight from 0.59 g to 0.79 g, a sample was obtained with a less dense membrane that contains many voids and a semi-micro large particle diameter is 97.32 nm for the sample P7. Finally, the sample P4 was selected with good crystalline and optical properties and a homogeneous surface formation with a high density that could enter into the special composition for the manufacture of optical devices with high efficiency and stability.

Calcium oxide (CaO) nanoparticle (NP) was synthesized by simple chemical method .The CaONPs was characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM) analysis and UV-absorption spectral studies. The average crystallite size was found to be ≈36nm and the band gap energy of CaO nanoparticle was 1.9 eV. Toxicity tests were performed on adult rabbits dosed with compound CaONPs for a period of (3 weeks).Areas of necrosis, haemorrhages and degenerations were seen histopathogically in kidney, liver after 3 weeks of administration of CaONPs, the data of hematologic obtained were statistically evaluated using Finney’s Probit Analysis and Toxicity test performed revealed that Ld50 value was 0.5ml/kg. In this study found that an increase in the proportion of calcium oxide in the blood leads to damage to the organs, like the liver and kidneys that responsible for filtering the blood.

Methyl ammonium lead iodide (CH3NH3PbI3) Perovskite was synthesized by a mixing method in one and two steps. The ethanol solvent was also used to dissolve CH3NH3I that is compared with isopropanol solvent. The characterizations of synthesized perovskite samples include the structural properties, morphological characteristics, and optical properties. The intensity and orientation in X-ray diffraction patterns appear clearly in ethanol solvent. Additionally, the ethanol solvent increases the grain size of perovskite which is homogeneous of the surface morphology. It causes a decrease in the wavelength of absorbance edge in addition to an increase in the energy bandgap value. The photodetector parameters for MAPbI3 perovskites cover the PbS nanocrystal which was prepared on the FTO glass dissolved by Isopropanol and DMF where the responsivity Rλ= 0.0037 and the quantum efficiency QE=1.016% was under λ nm =650 nm and Vbias=0V. These values were decreased by using Ethanol solvent.

The purpose of a surface plasmon resonance (SPR)-based photonic crystal fiber (PCF) biosensor is to achieve a maximal sensitivity for the detection of unknown analytes. Outside of the PCF, the chemically stable and inert plasmonic material gold (Au) was utilized. A solid core photonic crystal fibre (SC-PCF) with an endlessly single-mode was designed in this work, with both the centred core and holes in the cladding structured by circles. The SC-PCF was designed with a single solid center core surrounded by a six-ring hexagonal cladding. SC-PCF was measured utilizing the finite element method (FEM) and the perfectly matched layer (PML) boundary condition. The FEM was used to investigate the performance using COMSOL Multiphysics software. The proposed biosensor shows amplitude sensitivity of (167 to 886.38) RIU−1 within the sensing range of (1.3435 to 1.3471). Due to structural simplicity and excellent sensing properties, the proposed PCF can be regarded as a good biosensor.

The blending technology makes it possible to rebuild high molecular weightsof partial polymers, thus to improve the product performance together with improvement of specific properties.Pure Carboxymethylcellulose (CMC) film and CMC (80%) doped Polyacrylic Acid (PAA) (20%) films were prepared by using a solution casting method.The influence of PAA polymer addition on the structural and optical properties of CMC polymer was investigated systematically. From X-ray diffraction patterns, adding a polymer PAA to a polymer CMC can lead to the appearance of peaks in polymer blend.FESEM image for CMC/ PAA film showed the formation of small spherical grains for PAA into CMC that insured the existence of some peaks in XRD pattern of PAA in CMC film which means the improvement of the microstructure of the polymer matrix. No chemical interactions were observed between CMC and PAA polymers from results of FTIR spectrum, so that incorporation of PAA into CMC polymer will results physical reaction only. The results of the UV spectrum have shown that the absorbance, absorption coefficient, extinction coefficient, refractive index, real and imaginary dielectric constants were increased in blend polymer compared with the pure polymer. The energy gap and transmittance of blend polymer compared with the pure polymer were reduced.

The pure substance of Zirconium oxide (ZrO2) was deposited on substrate of glass with various substrate temperatures using thermal evaporation under pressure of (2×10-5mbar) and with a deposition rate of (0.5 nm/S) with an average thickness of (300 nm). The optical properties of these prepared films were concentrated as a function of the substrate temperature. It was found that the values of each of the refractive index, packing density, together with the extinction coefficient increased with the increase in the substrate temperature of the prepared films

Cr2O3NPs were synthesized using Okra extract with two methods; the simple chemical method and sol-gel method. XRD analysis showed that the crystal size of Cr2O3 in a simple chemical method was (16.15) nm and with sol-gel method were 16.6 nm, 16.14 nm and 16 nm using annealing temperature of 200, 400 and 600 °C respectively. FE-SEM analysis showed that the nanoparticles of Cr2O3NPs when using a simple chemical and the sol-gel methods, with particle sizes of (83.74-132.1) nm, (18.92-27.68) nm, (24.19-39.08) nm, and (12.04-15.83) nm that corresponding to a simple chemical method at 200 °C, sol-gel method at 200, 400 and 600 °C respectively. UV-Vis demonstrated that the band gap value of Cr2O3NPs was 2.9 eV with a simple chemical method,while in a sol-gel method was (3.15, 3.3, 3.5) eV at different temperatures. The study showed an effective antibacterial activity of Cr2O3NPs such was (12-14) mm of Gram's negative bacteria and (15-18) mm for Gram's positive bacteria in simple chemical method at (200) °C. The higher antibacterial activity of three different temperatures of sol-gel method was (20) mm for Gram's negative bacteria and (23) mm for Gram's positive bacteria at 200°C.

Pure Polyvinyl Alcohol (PVA) film and PVA polymer film/ Rhodamine 6G(Rh6G) dye film in different volume ratios of (6, 12,18, 24 and 30) ml of Rh6G were prepared via casting method. The addition of Magnesium Oxide (MgO) and Aluminium Oxide (Al2O3) nanoparticles as a filler to the polymer matrix. The results demonstrated that there was a 10 nm red shift in the absorption spectra of Rh6G in PVA/ Rh6G polymer matrix due to add doping ratio of Rh6G dye solution to the transparent PVA matrix. Also, there was a 5 nm red shift in polymer matrix filled with Al2O3NPs; this means that Al2O3NPs absorb the water and that consequently enhance the optical properties of polymer matrix. The intensity of Rh6G doped PVA polymer film was seen to be enhancedwhen adding MgO NPs or Al2O3NPs, noted that intensity of adding Al2O3NPs more than it when adding MgO NP. The electronic transition was found to be π→π*