فصلنامه نانو مقیاس
سال نهم شماره 2 (پیاپی 34، تابستان 1401)

Alumina abrasive particles are the main components in the preparation of polish materials in automotive industries. It is suggested that both particle size and crystallite size of alumina particles can drastically alter the final properties of as-prepared polish materials. Here we report a systematic study on controlling both particle size and the crystallite size of alumina particles during the ball milling and annealing process, respectively. Furthermore, we demonstrate how the change in particle size and crystallite size can change polishing time, glossiness. We suggest an optimal architecture for the alumina particles consisting of micrometer sized particles size consisting of nanocrystalline structure. We propose that this structure can satisfy the high cycle life and high quality of the paint needed for automotive industries. More importantly, no hologram effect was observed applying the process proposed in our study. However, for after-sales services, in which, the process time is less important, larger particle size are recommended to eliminate the high roughness.

In this paper, a direct deposition method was used to print graphene oxide/silver (GO/Ag) nanocomposites from silver nitrate and graphene oxide suspension with reduction using a non-thermal plasma jet. Aerosol droplets of the solution were reduced to GO/Ag nanocomposite in the plasma and deposited on the substrate. The hybrid materials were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy and Raman spectroscopy. The XRD results showed that the face centered cubic phase of Ag nanoparticles were developed in crystalline planes. The FESEM images confirmed that graphene oxide surfaces were decorated by Ag nanoparticles. The EDS analysis demonstrated that Ag was introduced on GO surface successfully via the plasma jet. GO exhibited distinctive Raman scattering for its D and G band, which were at 1355cm-1 and 1590cm-1, respectively, but they were weak for sensitive quantification purpose. By deposition silver nanoparticles on the surface of graphene oxide Both D and G bands of GO get enhanced.

In the present work, WO3/g-C3N4 and WO3/ g-C3N4/Cu2O nanocomposites containing tungsten trioxide and copper (I) oxide nanoparticles were synthesized on a graphitic carbon nitride substrate. The structural and morphological characteristics of the synthesized nanostructures were investigated by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), and diffuse reflection spectroscopy (DRS). The performance of nanocomposites as cathodic catalysts was investigated and compared in the photocatalytic water splitting process. The results showed that the WO3/g-C3N4/Cu2O nanocomposite produces the highest current density and the lowest overvoltage in the hydrogen evolution reaction. This improvement in photoelectrochemical performance can be attributed to the increase in surface area and electron transfer due to the synergetic effect between carbon substrate and oxide nanoparticles. In addition to practical studies, the WO3/g-C3N4/Cu2O nanocatalyst was simulated with Materials Studio software and the XRD pattern and its electronic structure were compared with the practical results. The theoretical XRD pattern showed good agreement with the experimental XRD pattern. Accordingly, the proposed nanocomposite can be well used as a cathodic catalyst in the production of pure hydrogen fuel.

In this paper, effect of gamma irradiation on structural and optical properties of CdTe/CdSe QDs were investigated for the first time. X-ray diffraction (XRD) results showed that synthesized QDs had cubic structure and gamma irradiation had no change in crystalline structure of CdTe/CdSe QDs. Also, Fourier-transform infrared spectroscopy (FT-IR) results confirmed that crystalline structure of CdTe/CdSe QDs had no change after gamma irradiation. The photoluminescence (PL) results showed that intensity of CdTe/CdSe QDs after gamma irradiation enhanced significantly. Shell thickness of CdSe and concentration of QDs were investigated as two important factor on optical properties of CdTe/CdSe QDs versus gamma irradiation. The results showed that less shell thickness and less concentration of sample make bigger changes in optical properties and band gap size of CdTe/CdSe QDs after gamma irradiation and with decreasing concentration of the QDs, the red-shift in PL peak was occurred stronger. Our obtained results showed that luminescence and absorption of CdTe/CdSe QDs have sensitivity versus gamma irradiation and CdTe/CdSe QDs are good candidate to use in dosimetry applications.

In this study is to measure and evaluate the effects of electron instability, dipole-dipole interactions on the structural and electronic properties, and the structural reactivity of the Fenoprofen drug. Quantum mechanical calculations of electron density function theory were performed to obtain the structural information and the dynamic behavior of two Fenoprofen enantiomers in the gas and solvent phases, at the B3LYP/6-31G* level of theory, and Nuclear Magnetic Resonance (NMR) shielding tensors were calculated by using the Gauge Independent Atomic Orbital (GIAO) method. Also, NBO (Natural Bond Orbital) analysis was performed to calculate the effects of electron transfer due to the interaction of electron stereo and dipole moments, reactivity indices, the energy of molecular orbitals, and bond gaps energy, the density of state (DOS), and molecular atomic charge density.According to the results of the energy calculations of both enantiomers, it was found that both Fenoprofen’s enantiomers, left-handed (S) and right-handed (R) have the same energy, and also according to the experimental studies, the S-enantiomer is more stable, so the rest of the calculations have been performed on the S-Fenoprofen enantiomer. The results of theoretical calculations at the level of B3LYP/6-31G* showed that the energy gap of the enantiomer is S-Fenoprofen (Eg =5.5265 eV). Determination of reactivity indices of S-Fenoprofen indicates high electron demand and hardness (stability) and low reactivity of this compound.

With the development of technology, and the expansion of using industrial paints, environmental pollution has become a general crisis today. Among the various methods, photocatalysis has attracted attention, because it is a simple, low-cost, and effective method for removing organic contaminants. Photocatalysis based on nanocomposites is an effective way of removal of industrial contamination. In this study, graphene oxide, and graphene oxide-silica/magnetite nanocomposites, were synthesized with three different weight ratios of magnetite. After structural characterization (XRD, UV-vis, VSM, FTIR, FESEM, EDS, TEM), their performance as an effective adsorbent, evaluated for removing methylene blue dye from aqueous solutions. The results indicate that graphene oxide-silica/magnetite (1:3) shows the highest degradation rate, about 94.95% compared to (1:2) and (1:1) samples with 92.52% and 88.46%, respectively. Therefore, by increasing the amount of magnetite, degradation percentage and photocatalysis efficiency increase.

In this study, copper oxide nanoparticles were synthesized by sol-gel method and characterizations were performed using of x-ray diffraction and dynamic light scattering (DLS), electron transition microscopy (TEM) and surface electron microscopy (SEM) which confirm the formation of 22 nm crystal structures. After that, gabapentin drug was applied to the particles in different amounts and loading process was studied by some methods such as; linear optical method (visible-ultraviolet spectrum) and nonlinear optical method (open-aperture z-scan method). In DLS measurements, it was observed that increasing the loading, increases the hydrodynamic radius due to the aggregation of particles or the formation of a drug halo around the particles, which leads to an increase in the light absorption of the material. Also, increasing the particle absorption increases the population of high level (conduction band) compared to low (capacity band) and colloid became saturated for light absorption, which was confirmed by open aperture z-scan experiment. The photoacoustic effect of copper oxide nanoparticles with blue laser was seen for the first time in this experiment, but unlike the results of other experiments, this effect cannot be a criterion to measure of drug loading. In summary, linear and nonlinear optical methods such as absorption spectrum and open aperture z-scan technique have been found precise methods to measuring amount of drug loading on copper oxide nanoparticles.

The aim of this study was to develop a cheap, selective, sensitive and practical method for detecting melamine in raw milk samples. Tris-dithiocarbamate was prepared by the reaction of 2-amino-2-hydroxy-propane-1,3-diol (tris base), as a cheap and available base, with carbon disulfide. Due to the presence of the dithiocarbamate together with the hydroxyl functional groups, there is a strong tendency to interact with melamine. Electron donor-electron acceptor interaction between melamine and tris-dithiocarbamate on the surface of silver nanoparticles leads to the aggregation of silver nanoparticles, which causes the absorption wavelength of nanoparticles to shift to higher wavelengths and the color of the solution changes from bright yellow to red. This color change has been recorded and measured using ultraviolet-visible (UV-Vis) spectroscopy. This method can be used to quickly measure the small amount of melamine in pasteurized milk samples. The detection limit of the method is 0.7 µM, and the sensor is completely selective towards melamine. The linear range of the method is 2 µM -12 µM, which is competitive with many similar methods reported.

Confinement of light at nanoscale dimensions in atomic plasmonic structures has many applications such as atomic line filters. In such coupled resonant systems, broad plasmonic resonance in contrast to narrow atomic resonance gives rise to reflection atomic spectroscopy with high resolution and very fine filter audiences. In this paper, an atomic-plasmonic cell was modeled and fabricated and the reflection from a thin gold layer in the vicinity of the rubidium vapor in Kretschmann configuration was measured by frequency modulation setup. By tuning the angle of incidence of light we could change the frequency of resonance of surface plasmon-polariton mode from the central frequency of atomic resonance lines, so the EIT to Fano resonance phenomena and vice versa have been observed. So, the EIT-like phenomena was introduced as an atomic line filter, controllable with light entrance angle.

In this study, nanocomposites with core-shell structure consisting of nickel ferrite and zinc sulfide were fabricated by rapid chemical method with the aim of enhancing the photocatalytic properties and were investigated in the ultraviolet region. Therefore, first samples containing nickel ferrite nanoparticles (NiFe2O4) were synthesized by co-precipitation method, then NiFe2O4-Zns nanocomposite with average diameters of 66 nm was made. The morphology and microstructure of the nanocomposites produced were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD analyzes show that the constructed nanostructures have a structure with a crystalline dominant phase. The magnetic properties of nanoparticles and nanocomposites prepared at room temperature were investigated using an alternating force gradient magnetometer (AGFM). The sample of nanocomposites produced using ultraviolet-visible (UV-Vis) optical spectrometer and the effect of the amount of adsorbent and irradiation time on the percentage reduction of dye concentration of solutions were investigated. The aqueous and methyl orange acids tested in the presence of the nanocomposite were significantly reduced, which is confirmed by the photocatalytic properties of the nanocomposite, which ultimately led to a reduction in the concentration of dyes used.

In this paper, the structural, electronic, optical, and photocatalytic properties of MXene monolayers are studied. MXenes are a new class of two-dimensional (2D) transition metal carbides and nitrides with the chemical formula Mn+1Xn (M = Sc, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta; X = C, N; n = 1–3) that etching MAX phases have recently synthesized. We study Hf2CO2 and Zr2CO2 nanostructures, comparing them with the GGA-PBE and HSE06 functionals. These calculations were performed using density functional theory (DFT). The unit cell of these structures and their atomic positions are fully optimized. The results show that the lattice constants for two-dimensional nanostructures Hf2CO2 and Zr2CO2 are 3.3592 and 3.3771 angstroms, respectively. The band gap of these nanostructures is of the indirect type. Based on the information obtained, their band gap values with GGA-PBE functional are 0.92 and 0.89 eV, respectively. The results of calculations with HSE06 hybrid functional show that both Hf2CO2 and Zr2CO2 nanostructures are semiconductors with band gaps of 1.75 and 1.72 eV. It can be seen that with an HSE06 hybrid functional, the amount of band gap improves. The real and imaginary parts of the dielectric function have been calculated to investigate the optical properties of these structures. In addition, the studied materials have high absorption in visible and ultraviolet regions. The obtained results show that these nanostructures may apply in designing optoelectronic devices.

Nano-sized of a new polymeric coordination [Co(H2O)2BDC]n (1), (BDC is benzene 1,4-dicarboxylate or terephthalate) (1:1), was synthesized by sonochemical method. The compound (1) was accomplished in three different concentrations of initial reagents (0.5, 0.25, 0.125M) and three different output power of ultrasonic generator (30, 60, 90W and ultrasonic bath with an output power of 50W). Nano-sized of compound (1) was characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and elemental analyses. The thermal stability of nano particles is studied by thermal gravimetric (TGA) and differential thermal analyses (DTA). The influence of various concentrations of initial reagents and power of ultrasound irradiation, on the morphology and size of nano-structured of compound (1), was studied. The compound (1) is then heated to 550o C to obtain Co3O4 nano particles. The nanoparticles of cobalt oxide are characterized by XRD, FT-IR spectroscopy and SEM images. Hirshfeld surface analysis revealed that the interactions O…O (25.7%), O···H (15.8%), C···O interactions (12.0%) and Co···O (9.0%) play the major role in the stability of the crystal structure.

Plasmonic nanoantennas provides a flexible platform for manipulating the interactions of matter and light at the subwavelength scale, and opens up new avenues for the design of high-performance optical devices. In this paper, we propose a broadband and polarization-independent absorber based on tungsten (W) as a refractory plasmonic metal. This three-layer nanostructure comprises of a thick tungsten film, a thin spacer of SiO2 with high-k dielectric on which a periodic array of tungsten octagram nanoparticles is deposited. The presence of several plasmonic polaritons with low decay rates in the proposed nanostructure provides a wide bandwidth from 250 to 1940 nm with more than 90% absorptivity. The bandwidth can be tailored by altering the thickness of the insulation layer and geometric dimensions of the nanoantennas. The proposed structure benefits from a planar, low profile and small footprint, and its optical characteristic is stable in a wide range of incident angle regardless of the polarization of the incident light. These features make the proposed metasurface a suitable candidate for high-efficiency conversion of solar energy in solar thermophotovoltaic systems.

Isocarboxazid is an antidepressant used to treat depression, panic attacks, obsessive-compulsive disorder, post-traumatic stress disorder, social anxiety disorder, body dysmorphic disorder, and severe premenstrual syndrome (PMS). In the present work, using the quantum mechanical method of density functional theory and using the base set B3LYP / 6-311 + G (d, p), chemical reactivity properties and adsorption of isocarboxazid on the surface of fullerene C60 molecule (ih) as carriers of the antidepressant drugs was calculated in the gas phase. Among the chemical properties, dipole moment was calculated in the study of solution properties, thermodynamic properties (Gibbs free energy, enthalpy, entropy, and heat capacity) and to detect the reactivity of electronic parameters (σ, µ, ω, χ, η). According to the calculated amounts of HOMO and LUMO energy, isocarboxazid is a stable and reactive compound that acts as a chemically active substance. This chemically active compound has seven active sites that lead to adsorption in the C60 nanocage as a drug carrier. This adsorption helps transport isocarboxazid to biological systems.

In this study, CaZrO3 nanophosphors with perovskite structure were synthesized by self-combustion method with citric acid as fuel at 350 °C and XRD patterns were performed at different temperatures to evaluate the optimum temperature of single-phase and crystalline CaZrO3 samples. The average size of crystals for the apparent peak (121) was estimated to be 44 nm using Scherer formula. The morphology of the samples using FE-SEM and EDXS indicated the nanometer size of the samples and the formation of desired phases in the sample. The photoluminescence (PL) emission spectrum of a sample under the excitation wavelength of 256 nm has a broad band around 435 nm (visible region) in the blue region of the electromagnetic spectrum. The results of thermoluminescence (TL) analysis also showed that the CaZrO3 sample made by this method shows TL properties even in the absence of impurities. Nanophosphors were irradiated with UV light at 254 nm at different times and its radiative peak was quite visible in the thermoluminescence curve at 204 °C. Also, CaZrO3 nanophosphors were irradiated with X-ray at different times and its thermoluminescence curve included a single peak at 209 °C. The linearity, reproducibility and fading of CaZrO3 were investigated under UV and X-ray irradiation.

In this study, the active ingredient of nano drug thalidomide was produced using asymmetric synthesis method. Asymmetric synthesis is one of the common methods in the field of nano drug synthesis. The active ingredient of thalidomide nano drug produced was investigated via different analyzes. To prove the synthesis of the produced nano drug, first Energy-dispersive X-ray spectroscopy (EDX) analysis was used. Then, the synthesis of nano drug thalidomide was studied using hydrogen nucleus magnetic resonance spectroscopy (HNMR) and Fourier transform infrared spectroscopy (FTIR). In the next step, a transmission electron microscope (TEM) was used to examine the nanometer structure of the synthesized drug. The nanometer dimensions of the synthesized drug were confirmed using the transmission electron microscope. Finally, in order to evaluate the improvement of the synthesized nano drug with normal drug, the release time of the drug in human stomach conditions was investigated and the release rate of thalidomide over time was evaluated using ultraviolet-visible absorption spectrometer (UV-Vis).

This study investigates the effect of changing the thickness of silver as an intermediate layer in SnO2 (100nm) / Ag (t) / SnO2 (100nm) three-layer structures on glass substrate using GLAD (glancing angle deposition) technique and DC/RF Magnetron sputtering method. Optical, electrical and thermal properties of the samples were studied. The results showed that SnO2 / Ag / SnO2 three-layer structures have the necessary conditions for use as thermal insulation coatings and energy storage on building windows. Considering the thickness of 30 nm for silver and 100 nm for SnO2, the values ​​of Emissivity, U-Value and G-Value are minimal and equal to 0.07, (W / m2.k) 1.44 and 0.481, respectively. As a result, heat transfer from the environment and sunlight from this coating is minimized. Also, the rate of passage in the visible area for thicknesses of 25 and 30 nm is maximum and equal to 71.18 and 62.3%, respectively.

In the present research, the structural and electronic properties of SnO2 nanolayer have been investigated using Quantum ESPRESSO integrated suite based on density-functional theory using ultrasoft pseudopotential approach and the generalized-gradient approximation. The pure structure of this slab model of SnO2 is semiconductor. The aim of this research is to investigate the effect of the impurities Pt, Sb, Ti, Cu, and Fe (in the magnetic part) on the aforementioned properties of SnO2 nanolayer. Examining the related bond lengths, band structures and density of states indicate that adding Pt, Sb, Ti, and Cu impurities enhances the conductivity of SnO2 nanolayer; adding Fe impurity also induces magnetic properties to the nanolayer.