Sharif Digital Repository

A novel method of oxide semiconductor nanoparticle synthesis is proposed based on high-voltage, high-current electrical switching discharge (HVHC-ESD). Through a subsecond discharge in the HVHC-ESD method, we successfully synthesized zinc oxide (ZnO) nanorods. Crystallography and optical and electrical analyses approve the high crystal-quality and outstanding optoelectronic characteristics of our synthesized ZnO. The HVHC-ESD method enables the synthesis of ZnO nanorods with ultraviolet (UV) and visible emissions. To demonstrate the effectiveness of our prepared materials, we also fabricated two UV photodetectors based on the ZnO nanorods synthesized using the subsecond HVHC-ESD method. The... 

Studies on copper zinc tin sulpher selenide (CZTSSe) thin-film material and its applications as a base material are intensively being researched since it is an earth-abundant, inexpensive, flexible, and interesting material for next-generation optoelectronic technologies. Apropos, this study explores and reports the synthesis of CZTSSe thin films and their key optoelectronics characteristics. The reported films are fabricated on a soda-lime glass substrate by using a physical vapor deposition technique, and then annealed from 250 to 450 °C. From the X-ray diffraction analysis, the structure of the as-deposited thin films is found to be amorphous in nature. Annealed thin films of CZTSSe... 

Studies on copper zinc tin sulpher selenide (CZTSSe) thin-film material and its applications as a base material are intensively being researched since it is an earth-abundant, inexpensive, flexible, and interesting material for next-generation optoelectronic technologies. Apropos, this study explores and reports the synthesis of CZTSSe thin films and their key optoelectronics characteristics. The reported films are fabricated on a soda-lime glass substrate by using a physical vapor deposition technique, and then annealed from 250 to 450 °C. From the X-ray diffraction analysis, the structure of the as-deposited thin films is found to be amorphous in nature. Annealed thin films of CZTSSe... 

An enhancement in heat transfer due to nanofluids is essentially required in various thermal systems. Hybrid nanofluids possess high thermal conductivity and, have ability to embellish and enhance the thermal strength of common fluids. Our concern in this paper is to examine the innovative attributes of hybrid nanofluids like Manganese zinc ferrite (MnZnFe2O4) and Nickel zinc ferrite (NiZnFe2O4) in the bio-convective flow of motile gyrotactic microorganisms subject to Darcy Forchheimer medium. The effect of activation energy has also been taken into account. Mathematical treatment is carried out via MATLAB software. The use of MnZnFe2O4 - NiZnFe2O4/H2O exhibits improved thermal... 

The structural and dielectric properties of Gadolinium substituted U-type hexaferrites (Sr4Zn2Fe36O60) were investigated. The samples were synthesized via the Sol-gel auto combustion route. In a muffle furnace, these samples were sintered for 5 h at 1250 °C. The pellets of synthesized powder samples were characterized by XRD, PL, Dielectric, FTIR, and Raman spectroscopies. Structural elucidation of Sr4Zn2Fe36-xGdxO60 was done via XRD. The obtained XRD patterns were matched with the prior literature. The impact of Gd3+ substitutions was measured on all the lattice parameters. Lattice constants “a" and “c" were found between 5.871 and 5.900 Å and 111.76–112.23 Å, respectively. The PL spectra... 

Over the past few decades, biological hazards and organic pollution have become major environmental concerns. Photocatalysis has been found to be effective in minimizing the negative impacts of these issues in air and water. Lozenge shape Ag/AgCl/ZnTiO3 photocatalysts were fabricated by a facile two-step synthesis method, including hydrothermal and coprecipitation. The physicochemical characteristics and morphological properties of the structures were comprehensively described taking advantage of a multi-technique approach. The prepared photocatalysts offered excellent nitrophenol mineralization (>90%) after 90 min of visible light irradiation. Based on the spin-trapping ESR technique, •O2̅–... 

Hybrid nanofluids are new and most fascinating types of fluids that involve superior thermal characteristics. These fluids exhibit better heat-transfer performance as equated to conventional fluids. Our concern, in this paper, is to numerically interpret the kerosene oil-based hybrid nanofluids comprising dissimilar nanoparticles like silver (Ag) and manganese zinc ferrite (MnZnFe2O4). A numerical algorithm, which is mainly based on finite difference discretization, is developed to find the numerical solution of the problem. A numerical comparison appraises the efficiency of this algorithm. The effects of physical parameters are examined via the graphical representations in either case of... 

Low-cost inorganic hole-transporting materials (HTMs) accompanied by a printable carbon electrode is an efficient approach to address the limitation of material cost of perovskite solar cells (PSCs) and get this technology closer to commercialization. The present work is focused on optimizing the Zn/Sn ratio of Cu2ZnSnS4/carbon hole collectors in n-i-p structured PSCs, where CuInS2/carbon is applied as the reference hole collector. This composition regulation is a solution to address the challenge of composition-related defects of the Cu2ZnSnS4 (CZTS) material. The Zn/Sn ratio was tuned by the initial proportion of the zinc precursor during the nanoparticle (NP) synthesis using a heating-up... 

High-performance photodetectors play critical roles in numerous photon-based applications in imaging, communication, and energy harvesting. Nowadays, heterostructures have received significant attention to extend the performance of photodetectors, with exceptionally high optical absorption and a wide absorption range. However, the enhancement factors, exact mechanism, and facile fabrication procedures are long-standing problems. Here, a heterojunction of a two-dimensional chemical vapor deposition-grown monolayer of WSe2with a Cu2ZnSnS4(CZTS) film is introduced. The CZTS film as an abundant material was synthesized in the form of nanoparticles, and it showed a great effect on the enhancement... 

Cu2ZnSnS4 (CZTS) is a good candidate for cost-effective perovskite solar cells (PSCs) due to its direct bandgap with a value of 1.4–1.5 eV. In this study, we investigate CZTS ink as an inorganic hole-transport-layer (HTL) in CsMAFAPbIBr mixed halide PSCs. We study the cell efficiency and hole extraction from the perovskite layer for different thicknesses of HTL. The optimized device exhibits better hole selectivity, and the best efficiency of the device (12.84%) is achieved for the CZTS layer with a thickness of 159 nm. The prepared samples were also tested by open-circuit voltage decay analysis and electrochemical impedance spectroscopies. Results show that the optimized device effectively... 

In this paper, a high-performance epoxy nanocomposite with dual active/barrier protection ability based on calcium zinc phosphate (CZP) nanopigment was fabricated. Then chemistry, morphology, and anti-corrosion ability of the commercial zinc phosphate (ZP) and CZP pigments were studied. By electrochemical techniques, the inhibition potency of the CZP nanopigment was examined in a NaCl solution on mild steel (MS) substance and compared with that of ZP. Results revealed a higher corrosion inhibition degree of the CZP compared to the ZP. The growth of a protective layer on the metal coupons exposed to the CZP extract was illustrated by X-ray photoelectron spectroscopy (XPS), field emission... 

Hollow microblocks of [Zn(anic)2], as a novel coordination compound, were synthesized using 2-aminonicotinic acid (Hanic) and zinc (II) nitrate tetrahydrate. The chemical composition of the zinc complex, ZnC12H10N4O4, was determined by Fourier transform infrared (FTIR) spectroscopy and elemental analysis. The synthesized zinc complex was used as a precursor to produce ZnO nanostructures by calcination at 550 °C for 4 h. Morphological studies by scanning electron microscopy and transmission electron microscopy revealed the formation of porous microbricks of ZnO nanoparticles. N2 adsorption-desorption analysis showed that the... 

In this article, indium doped ZnO nanoparticles (alloy nanoparticles) were investigated as inhibitors against algae growth on adobe mud and earthen artworks for surface preservation from destruction caused by micro-organisms under humid conditions, through surface modification and activation run off. Nanoparticles (NPs) were fabricated by physical vapor deposition (PVD) growth mechanism. The fabricated NPs were approximately 20 nm in size. The Chlorella vulgaris and Scenedesmus quadricauda were tested by application of indium doped ZnO nanoparticles (In/ZnO NPs) as inhibitors. As concentrations of NPs increased, the negative impacts of NPs on the algal growth were enhanced and physical... 

Comprehensive structural/molecular simulations have been undertaken to study the poly(benzimidazoles) (PBI) membrane combined with four different nano-oxide materials (ZnO, Al2O3, SiO2 and TiO2) for purification and production of hydrogen from natural gases. Composite membranes were built with different amounts of nano-oxide materials to investigate the influence of nano-oxide content on the PBI membrane performance. Several structural characterizations such as FFV, WAXD and also a thermal one (glass transition temperature) were done to study the structural properties of all simulated membrane cells. Moreover, MSD and adsorption isotherms tasks were used to estimate the diffusivity and... 

We produced ZnO nanoparticles by high current electrical arc discharge of zinc electrodes in deionized (DI) water. X-ray diffraction (XRD) analysis shows formation of crystalline ZnO phase with hexagonal structure and 14 nm single crystalline domain size. Dynamic light scattering (DLS) result indicates that at 5 A arc current, the size of the particles is about 100 nm and increases by increasing the arc current. Absorption spectroscopy of the samples obtained at different arc currents shows an absorption edge on 370 nm which has a red shift by increasing the arc current. Band gap of the produced ZnO nanoparticles at 5 A arc current corresponds to 3.8 eV which decreases to 3.3 eV by... 

In this paper, the stable and reproducible tellurium doped ZnO nanowires (Te-ZnO NWs) photodetector with intensive responsively is presented. The Te-ZnO NWs were fabricated by physical vapor deposition (PVD) growth mechanism. Field emission scanning electron microscope (FESEM) images showed that the fabricated nanowires were 50 nm in diameter and several microns in length. The high resolution transmission electron microscopy indicated that the synthesized nanowires were crystalline and their phase characterization was validated by the X-ray diffraction (XRD). The photoluminescence (PL) studies of these nanowires showed a strong photoluminescence (PL) emission peak in the green region. It was... 

Application of corrosion resistant coatings is one of the most widely used means of protecting steel. Zinc coated (galvanize) steel, is well known for galvanic protection of steel substrates and nowadays, particular attention has been paid to the coupling of graphene oxide (GO) with metallic materials, in order to lessen corrosion rate. In this research, an isopropanol supercritical reducing environment prepared to make zinc ions bond directly with graphene oxides, to form a button shape hybrids of ZnO-Graphene (ZnOG). The hybridized bonding between zinc and graphene oxide is confirmed by Fourier Transform Infra-Red analysis. And the morphology revealed, using a Field Emission Scanning... 

Two new macrocyclic ligands Ln (L and L′) bearing two fluorophore naphthalene moieties were synthesized and characterized by employing 1H and 13C NMR, IR, microanalysis as well as mass spectrometry. Comparative studies on the effect of assorted metal cations as Cr(III), Cu(II), Zn(II), Cd(II), Pb(II), Na(I), Ni(II), Co(II), Ba(II), Fe(II), Al(III), Mg(II), Cs(I), Ca(II), Hg(II), K(I), Mn(II), Ag(I), Fe(III) on fluorescence and UV–vis spectra of Ln in ethanol illustrated that both of the macrocycles were sensitive and selective fluorescence chemosensors for Al(III). Remarkable binding constant values as 1.36 × 105 M−1 and 1.15 × 105 M−1 alongside 1:1 stoichiometry for Al(III)/L and Al(III)/L′... 

Two new macrocyclic ligands Ln (L and L′) bearing two fluorophore naphthalene moieties were synthesized and characterized by employing 1H and 13C NMR, IR, microanalysis as well as mass spectrometry. Comparative studies on the effect of assorted metal cations as Cr(III), Cu(II), Zn(II), Cd(II), Pb(II), Na(I), Ni(II), Co(II), Ba(II), Fe(II), Al(III), Mg(II), Cs(I), Ca(II), Hg(II), K(I), Mn(II), Ag(I), Fe(III) on fluorescence and UV–vis spectra of Ln in ethanol illustrated that both of the macrocycles were sensitive and selective fluorescence chemosensors for Al(III). Remarkable binding constant values as 1.36 × 105 M−1 and 1.15 × 105 M−1 alongside 1:1 stoichiometry for Al(III)/L and Al(III)/L′... 

Here, the carboxamide ligand N-(thiazole-2-yl) picolinamide (L) was synthesized in an ionic liquid tetrabutylammonium bromide (TBAB) as the benign reaction medium. The sensitivity of L towards different metal-ions was investigated, and a comprehensive, logical optical investigation was conducted for the IIB transition metal ions, Hg2+, Cd2+ and Zn2+, based on off-on switch sensor protocols. In the absence of these metal ions, L showed weak emission only, but fluorescence intensity increased considerably upon their addition to a sensitivity range of 10-6 M. This phenomenon was enhanced significantly in the presence of Zn2+ compared to other metal ions, likely due to the coordination of...