Sharif Digital Repository

This study represents the investigation of In2S3 thin films, which have been deposited with different Indium salts (Chloride, Acetate, and Nitrate) using the Chemical Spray Pyrolysis (CSP) method. The Mott-Schottky analysis has been used in case of studying the electrical properties of films such as conduction and valence band, carrier densities, Fermi level (Efn), flat band potential, and semiconductor type. In the next step, the Rb1MAFA perovskite solar cell has been simulated, and the results have been validated by the experimental data (with the least parameters for fitting). Finally, In2S3 layers have been inserted on the SnO2 layer to decrease the recombination rate and enhance the... 

We investigate the use of simple nontoxic Cu2SnS3 (CTS) nanoparticles (NPs) as low-cost dopant-free hole-transport materials (HTMs) a substitute for spiro-OMeTAD in an n-i-p mesoscopic architecture of perovskite solar cells (PSCs). Besides, this work confirms the critical role of the crystalline phase of CTS NPs on the performance of the device. Using a facile one-pot heating-up procedure, pure zincblende and wurtzite structures of CTS NPs were obtained by sulfur element and thiourea as the sulfur source, respectively, and were dispersed in chloroform to make very stable nonpolar ink that is compatible with the perovskite. Nanoparticles with the wurtzite crystal phase showed much better... 

The transformation of gibbsite to α-alumina occurs in the range 1100 to 1300°C. The higher the calcination temperature, the larger the crystallites and this leads to abnormal grain growth. The main goal of this research was to reduce the transformation temperature of gibbsite to α-alumina by reducing the gibbsite particles size. The sodium content of the gibbsite used in the study was reduced to less than 0.1% by washing it in HCl solution. It was then ground in a fast mill at ambient conditions for different times then calcined at different temperatures. The microstructure, particles size and thermal behaviour of the samples were examined with SEM, XRD, XRF, PSA and STA, respectively. In a... 

The presence of dyes as pollutants in wastewater sources from textile industries can cause significant health issues if they are not adequately treated. Dye adsorption to entrap contaminants in nanoparticle pores has created considerable attention in recent years due to the environmental concerns occurring as a result of spillage of dyes in water bodies. In efforts to understand adsorption capability UiO-66, metal-organic frameworks (MOFs) were developed and examined for the separation of four pollutant dyes containing methyl red (MR), methyl orange (MO), malachite green (MG), and methylene blue (MB), which are widely used in textile industries. The adsorbent structural stability in water,... 

Gold-catalyzed cyclization of 1,5-diynes with ketones as reagents and solvent provides diversely substituted vinyl ethers under mild conditions. The regioselectivity of such gold-catalyzed cyclizations is usually controlled by the scaffold of the diyne. Herein, we report the first solvent-controlled switching of regioselectivity from a 6-endo-dig- to 5-endo-dig-cyclization in these transformations, providing fulvene derivatives. With respect to the functional-group tolerance, aryl fluorides, chlorides, bromides, and ethers are tolerated. Furthermore, the mechanism and selectivity are put to scrutiny by experimental studies and a thermodynamic analysis of the product. Additionally,... 

The purpose of this research is to explain the surface modification of fabricated polyamide reverse osmosis (RO) membranes using UV-initiated graft polymerization at different irradiation times (15, 30, 60, and 90 s) and various acrylamide concentrations (10, 20, and 30 g L−1). Also, coating of membranes surface with various concentrations of TiO2 nanoparticles (10, 20, 30, and 50 ppm) followed by the same UV irradiation times was investigated. After that, the membranes modification was done by grafting of acrylamide blended with TiO2 nanoparticles via UV irradiation. The characterization of membranes surface properties and their performance were systematically carried out. The results... 

Three-dimensional macroporous fluorine-doped tin oxide (p-FTO) films were successfully deposited using commercial ink of FTO powder and SnCl2 salt via Dr. Blade method. Various features of p-FTO thin films were studied as a function of the ink composition and sintering temperature. The morphological studies corroborated formation of porous, uniform, and crack-free FTO films after annealing at 300 °C for 10 min in air. X-ray diffraction pattern demonstrated development of highly crystalline FTO films. The lowest sheet resistance of 47 Ω/□ was obtained for the p-FTO film with a thickness of 21 μm. The capacitance of thin p-FTO films was investigated using a three-electrode system and the... 

The early stages of nucleation and growth of nanostructures can control the shape and final size of the fabricated nanostructure. Therefore, the study of the nucleation and growth mechanism of nanostructures is of great importance. The purpose of this study is to investigate the nucleation and growth mechanism of nickel nanocones from a chloride-based bath containing ethylene ammonium dichloride as a crystal modifier. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry tests were employed to investigate the nucleation and growth mechanism and also the mechanism of crystal modifier performance on the growth of nanocones. Electrochemical studies revealed... 

A new gelator based of oleylamide has been introduced, which was gelled nonpolar hydrocarbon and CCl4 solvents through self-assembly. Also, the gelator formed a two-component hydrogel in combination with SDS, an anionic surfactant. UV-Vis studies revealed that the H-type and J-type aggregation of organogels in hexane and hydrogel in water, respectively. The xerogel, obtained by evaporating the solvent of organogel, selectively gelled and adsorbed oil spills on water surfaces. The effect of the various parameters, including temperature, water acidity and pH on the oil spill adsorption was studied, revealing the high ability of the xerogel to removing the oil contamination from water in up to... 

In the present study, a rational two-step strategy is employed for the green, fast, very simple, and highly controllable synthesis of the bimetallic nickel-cobalt-based metal-organic frameworks (MOFs) on glassy carbon substrates by in situ transformation of nickel-cobalt-layered double hydroxide nanosheet (NiCo-LDHs NSs) intermediates into nickel-cobalt-benzene tricarboxylic acid MOFs (E-NiCo-BTC MOFs). The structural characteristics of the electrode materials in each step were investigated via Fourier transform infrared spectroscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, elemental mapping, field emission scanning electron microscopy, and transmittance electron microscopy.... 

Lignocellulosic materials are recalcitrant to bioconversion, due to their rigid physiochemical structure. In this work, the effects of Fe2O3–TiO2 and NiO–TiO2 nanoparticles (NPs) and FeCl3 and NiCl2 salts, on the anaerobic digestion (AD) of wheat straw have been investigated. For this purpose, metal oxide-TiO2 NPs were synthesized and fully characterized. Results showed that addition of 0.252 mg of NiO–TiO2/g total solids (TS) to batch assays resulted in increase of soluble chemical oxygen demand (COD) and 67% increase in volatile fatty acids (VFAs) concentration compared to control tests during the first 4 days of experiments. These results indicate that hydrolysis and acidogenesis rates... 

Purpose: This paper aims to study peroxymonosulfate (PMS) activation in the ultraviolet (UV)/ozone process for toxic cyanide degradation from aqueous solution by a novel and simple method. Design/methodology/approach: Photocatalytic degradation of cyanide (CN-) was carried out using a bench-scale photoreactor. Optimization of the UV/ozone process for the highest removal of cyanide was obtained. The effect of parameters such as ozone concentration, PMS concentration, temperature, cations (Cu2+, Co2+ and Fe2+), cyanide concentration, anions (bicarbonate, carbonate, chloride, nitrite, nitrate and sulfate [SO42−]) and scavengers (ethanol [EtOH], humic acid, TBA and NaN3) was investigated for CN-... 

Efficient electron transport layers (ETLs) play a pivotal role in the performance of solar cells. In recent years, Indium sulfide (In2S3) has been studied as a promising ETL in CuInGaS(e)2, Cu2ZnSnS(e)4, and perovskite solar cells. Despite several studies on spray-deposited In2S3, there is no complete experimental investigation on In2S3 thin films. The effect of the molar ratio of S/In and the type of indium precursor on the structural, morphological, optical, and electrical properties of sprayed-In2S3 layers has been studied. Films were characterized using x-ray diffraction, scanning electron microscopy (SEM), optical transmission (UV-Vis), Mott-Schottky analysis, four-point probe, and... 

In this study, zirconia antistatic coatings were synthesized by a simple dip coating sol-gel route on glass substrates, then applied to polymer-based composites to potentially improve their dust or water repellent capabilities. The coating solution contained a precursor (ZrCl4), solvent (isopropanol) and coupling agent. FTIR spectra confirmed ZrO2 and ZrO compounds in both solution and antistatic coating. FE-SEM images indicated ZrO2 fibers’ thickness was controlled by changing ZrCl4 concentration (150 g–15 g ZrCl4/l) or relative humidity (20%–60%) during coating drying. Fibers grew thicker when decreasing the former or increasing the latter. The surface electrical resistivity for all... 

The Zr-based metal-organic framework (MOF, UiO-66) was synthesized solvothermally. The synthesized UiO-66 was activated using different solvents (acetone, chloroform, and ethanol) via two activation methods of centrifugation and Soxhlet extraction over different periods (1–10 days). The crystalline structure and morphology of the synthesized UiO-66s were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption, and field-emission scanning electron microscopy (FESEM) techniques. The adsorption behaviors of the synthesized UiO-66s were then investigated by selecting anionic methyl red (MR) and cationic methylene blue (MB) as the model dyes. It was found that a change in... 

Co-precipitation of CoCl2.6H2O with graphene oxide (GO) and heating at 400°C for 4 h under hydrogen resulted in the construction of cobalt/ reduced GO (Co/rGO) nanocomposite utilisable in magnetic thermal therapy. Field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, vibrating sample magnetometry, thermogravimetric analysis/derivative thermogravimetry, and X-ray diffraction methods characterised the samples. Time-temperature curves of the samples containing 30, 50, 70, and 100 µg ml−1 Co/rGO nanoparticles (NPs) suspended in phosphate-buffered saline were determined at different specific heating rates. Magnetic-field response of... 

In this research, we investigate the effect of alkali metal cations including Li, Na and Cs in hydrothermal solution on the morphology, stability, and photoactivity of nanostructured TiO2 nanoflakes as a photoanode. The TiO2 nanoflakes are formed through hydrothermal treatment of Ti foil in 1.0 M LiOH, NaOH or CsOH at 100 °C for 3 h. By subsequent thermal reduction of the structure in an optimized Ar/H2 environment, conductive TiO2 nanoflakes were formed. The reduction treatment remarkably improves the photocurrent density of the TiO2 nanoflakes and has the highest impact on the sample treated in the NaOH alkali solution. For the nanoflakes produced in NaOH alkali solution, the bandgap is... 

The complexes PdII(qcq)(OAc) and PtII(qcq)Cl have been synthesized using environmentally benign synthesized ligands and characterized by elemental analyses: Fourier transform infrared spectroscopy, UV–visible spectroscopy, 1H NMR spectroscopy, and X-ray diffraction. The catalytic activity of the complex was assessed, in different media, for the Mizoroki–Heck coupling reaction for typical aryl halides and terminal olefins under aerobic conditions. Since the base and the solvent were found to influence the efficiency of the reaction, reaction conditions, temperature, time, and the amount of K3PO4 and a mixture of H2O/PEG, were optimized. We found, for the Mizoroki–Heck reaction coupling less... 

A multi-residue method using gas chromatography coupled with flame ionisation detector has been developed for simultaneous determination of 10 pesticides in milk. The methodology involved a sample clean-up procedure using ‘quick, easy, cheap, effective, rugged and safe’ followed by a preconcentration step based on dispersive liquid–liquid microextraction. In this regard, acetonitrile was added to the milk sample with specific pH and ionic strength, and the mixture was rigorously shaken. The extracts were centrifuged; then, the organic phase (acetonitrile) was transferred to a test tube and was mixed with deionised water. The mixture was sonicated and chloroform was added as an acceptor phase... 

Understanding the roles of asphaltene and resin as natural surfactants existed in crude oil can enlighten contradicting reported results regarding interfacial tension (IFT) of crude oil/aqueous solution as a function of salinity and ion type. In this way, this study is aimed to investigate the effect of these natural surface active agents on IFT of with special focus on SO42− anion and Mg2+ cation. Two different synthetic oil solutions of 8 wt% of the extracted asphaltene and resin dissolved in toluene are prepared, and then IFT values are measured. After that, the obtained results are compared with the IFT of intact crude oil in contact with the same saline solutions examined in the...