نشریه تحقیقات در علوم مهندسی سطح و نانو مواد
پیاپی 2 (تابستان 1401)

In recent years, towards the development of emerging technologies related to renewable energies, the Perovskite solar cells have been the focus of many researchers in applied sciences and optoelectronic industries. Among these, metal-organic halide perovskite materials have shown many remarkable characteristics, including high light absorption range, tunable band gap, low exciton binding energy, and long diffusion length of charge carriers. These characteristics make these materials occupy a special place in emerging photovoltaic technologies. In this research, with the aim of creating a better understanding and gaining a more complete insight about solar cells based on metal-organic halide perovskite materials, a part of a comprehensive review of this type of technology, which includes the introduction of the crystalline structure of perovskite materials, the study of architectural types and familiarity with the manufacturing methods of lead-based perovskite solar cells are investigated.

The purpose of this research is to investigate the effect of ferritization of primary powders and the time of heating in a microwave oven on the properties of the glaze created on the 316 stainless steel substrate. The desired glaze was made of TiO2, SiO2, MgO and Al2O3 powders. One series of powders was heated in the furnace for 2 h before glazing and immediately cooled in water (ferrited) and one series was directly microwaved (non-ferrited). Then the samples were cooked for 10, 20 and 30 minutes. The created glazes were evaluated by scanning electron microscope and Xray powder diffraction, hardness and adhesion tests. Microscopic images showed that with the increase of heating time, the amount of holes in the glaze is reduced and completely dense glazes are created. Porosity in nonferrite glazes caused a decrease in hardness and lack of proper adhesion of the glaze to the substrate. The hardness and stickiness of the ferrite glazes were much higher than the non-ferrite glazes.

In this study, structural characteristics and linear and nonlinear optical properties of TiO2/ZnO nanocomposite were investigated. In the first step, TiO2/ZnO composite nanostructure was prepared via a two-stage chemical coprecipitation approach by adding TiO2 nanoparticles into an aqueous solution containing zinc acetate precursor. In a second step, pure TiO2 and ZnO nanoparticles were synthesized by a co-precipitation method to investigate the presence portion of the basic structures on linear and nonlinear optical properties of TiO2/ZnO nanocomposite. Phase identification and chemical analysis of assynthesized nanostructures were performed by X-ray diffraction (XRD) crystallography and Fourier transform infrared (FT-IR) spectroscopy. Elemental properties of samples were studied by energy dispersive X-ray spectrometer (EDS) and surface mapping recorded by field emission scanning electron microscopy (FE-SEM). The morphological studies of the as-synthesized nanocomposite were analyzed by transmission electron microscopy (TEM). Linear optical studies were carried out to achieve the optical absorption edges and band-gap energies using UVVis spectra. Standard single-beam Z-scan technique with open-aperture (OA) and closed-aperture (CA) setups was utilized to determine nonlinear refraction index and nonlinear absorption coefficients, respectively. The optical nonlinear results showed a third-order optical susceptibility from the order of 10-4 esu under 532 nm laser radiations. 

In this research a spinel type double oxide nanopowder LiMn0.5Co1.5O4 was prepared by sol-gel method and its structure was identified using X-ray diffraction, thermal analysis, scanning electron microscopy and infrared spectroscopy methods. The X-ray diffraction pattern (XRD) showed that after the calcination, only the pericardial phase with spinel structure was formed. After identification and characterization of synthesized spinel, phosphate removal process was investigated. In this process, various parameters such as time, adsorption concentration, dye concentration and pH were studied.

Considering the importance of edible vegetables in daily nutrition, the present study was conducted with the aim of investigating the effect and application of cumin essential oil nanoemulsion (Cuminum cyminum) in order to control pathogenic bacteria and parasites in lettuce (Lactuca sativa). The total bacterial count of lettuce under the effect of cumin nanoemulsion showed a significant decrease compared to water treatment, so the lowest microbial load was measured in 0.1% cumin treatment and the highest microbial load was measured in water treatment. Cumin nanoemulsion had more antibacterial effect on Vibrio cholerae (gram negative) and Listeria monocytogenes (gram positive) compared to salmonella typhimurium (gram negative) and Escherichia coli (gram negative).. In the investigation of the number and types of parasites isolated in different washing stages, nematode larvae, cysts of Giardia, Ascaris eggs, entambacoli cysts, and taenia eggs were isolated.

In this research, friction stir spot welding on aluminum plates 7075 and 6061 was performed. The purpose of this work is to investigate the impact of the tool's hardness and its rotational speed by changing the layout of the plates on the mechanical properties of the made welds. Two tools were made of H13 steel, with different hadness was used. The mechanical properties of the weld were studied for shear strength and microhardness. The results showed that when the 6061 aluminum plate is located on top of the layout, the shear tensile strengths are less than the 7075 aluminum plate. Also, with the increase in the speed of the tool, the shear force force values have undergone a downward trend. The microhardness of the heat treatment device is higher than the microhardness of the raw material. Also, with increasing speed of tool, the obtained microconstability has a rising trend. This is due to the increased frictional heat transferred by the very high speed of the tool, which increased the hardness of the boiling region. The optimum mode is achieved at a speed of 1000 rpm and in a position where aluminum 7075 was placed on top of the plates.