فصلنامه نانو مقیاس
سال هفتم شماره 2 (پیاپی 26، تابستان 1399)

Nowadays, aminopropyl functionalized mesoporous silica MCM-41 is known as a potential anticancer-drug delivery system with a high surface area. In this work, so as to produce an image-guided drug delivery system for diagnostic applications, proto porphyrin was radiolabeled with 67Ga radionuclide and this complex was grafted on 3-aminopropyl functionalized MCM- 41. The nanoparticles were assessed with radio thin layer chromatography RTLC, X-ray diffraction, FTIR spectroscopy, surface area analysis BET and ThermogravimetrY.

In present research, fabrication of doped TiO2 nanorods ‎by importing aluminum oxide as dopant via using the sol-gel method and alkaline corrosion ‎are reported. The morphologies, topography, nano crystal structures and electrical properties of TiO2 ‎nanorods are characterized. Degradation rate of methylen ‎blue MB in its aqueous solution under UV irradiation is investigated as an ‎amount of photocatalytic activity. The presence of aluminum oxide dopant to the TiO2 matrix promotes the photocatalytic activity because of the thermal stability and raising the surface area. Dependence between photocatalytic activity ‎and calcination temperatures is specified. Dielectric constant, capacity, quality ‎factor and resistance are measured. Moreover, the effects ‎of aluminum oxide dopant and calcination temperatures on surface topography, crystallization ‎of phases, dielectric constant, electrical resistance, lattice strain and activation ‎energy of nanoparticles formation are studied. The obtained results show that aluminum oxide-doped TiO2 nanorods have higher dielectric constant, higher photocatalytic activity, less leakage current, less roughness surface, less lattice strain and higher thermal stability. Therefore, these nanorods have the potential to be a suitable candidate as a gate dielectric material for the future of FETs.

In this work, NiCo2S4 nanostructures were grown on nickel foam by using chemical bath deposition CBD method for the costruction of high performance supercapacitor electrode. The morphology of the samples was characterized with scanning electron microscopy SEM and the supercapacitive behaviour of the electrode was investigated by various electrochemical techniques including cyclic viltammetry CV, galvanostatic charge-discharge GCD and electrochemical impedance spectroscopy EIS. The fabricated electrode provided a specific capacitance of 303 mF cm-2 at 1 mA cm-2 in 1.0 M KOH. Electron transfer resistance Rct of the electrode was studied by EIS and obtained to be 5.5 Ω. The electrochemical performance parameters of the fabricated electrode showed that the proposed metal sulfide-based composite is an appropriate electrode for the supercapacitor applications.

The Electron transport layer ETL plays an essential role in the solar cell Performance. In recent years, In2S3 has been used as ETL in photovoltaics such as CZTS, Se, CIG S, Se and Perovskite thin film solar cells. In this study, the easy and inexpensive spray pyrolysis method was used to fabricate In2S3 layers. The effect of indium salt type on the electrical, optical, structural and morphological characteristics of the as-sprayed In2S3 layers was investigated. Regarding this target, the Characterization techniques including X-ray diffraction XRD, Field emission electron microscopy FESEM equipped with elemental analysis EDS, UV-Vis spectrophotometer, Mott Schottky electrochemical analysis and four-point probe resistance analysis were used. The indium source chloride, nitrate and acetate salts has strong influence on the crystallinity and morphological properties. The layers resulted from precursor including indium acetate salt, are highly porous compared to the other two precursors. Whereas, the best crystallinity and lowest electrical surface resistivity by using the chloride salt were obtained. In addition, the surface resistance decreases dramatically with increasing substrate temperature. Although the prepared In2S3 layers all have n-type conductivity and indirect band gap of ~2 eV, the energy levels of the band structure varies by changing the Indium salt. The density of the majority carriers electrons also varies from 2.1 × 1017 cm-3 to 2.9 × 1019 cm-3. The highest carrier density is related to the sprayed layers at 420 °C consuming Indium acetate salt.

Removing dye pollutants from industrial waste water is a common environmental application of nanomaterials. This study investigated in-situ synthesis and adsorbing ability of a magnetic nanocomposite based on graphene for both cationic and anionic dyes. To determine composite structure, chemical bonds, morphological and magnetic features X-ray diffraction XRD, Fourier transform of infrared spectroscopy FTIR, Field Emission Scanning Electron Microscopy FESEM and Vibrating-sample magnetometer VSM were examined and adsorbent capacity function of solution pH, time of removal and material content for Methyl Orange MO, Methylene Blue MB, Crystal Violet CV and Rhodamine B RhB by two method Isotherm Langmuir and Isotherm Freundlich were studied. Experimental results of Iron-Graphene nanocomposite showed average removal adsorbent of 70 in 30 minutes and removing by external magnetic field in a minute. This study shows that the synthesized magnetic nanocomposite advances for high amount of pollutant cleaning in a short time by using small amount of materials.

In this work, the effect of alkali and alkaline earth cations on modified silver nanoparticles AgNPs was investigated. The nanoparticles were used as a simple and low-cost colorimetric sensor for detecting alkaline earth metal cation. The determination process was based on the surface plasmon resonance properties of AgNPs. Interaction of AgNPs with alkaline earth metal cations in the presence of cysteine molecules induced a red shift in the surface plasmon resonance SPR maximum of AgNPs, as a result of nanoparticles aggregation. Consequently, yellow color of AgNPs solution was changed to pink. The examined cations were consisted of Mg2 , Ca2 and Ba2 . The calibration curve was obtained for each cation. Limit of detection, linear range and sensitivity of each cation was obtained and compared. The best detection limit and sensitivity were observed for Ba2 ions. Thus, this method was applied to the determination of barium ions in aqueous samples. In order to eliminate the interferences due to the presence of other cations, all measurements were carried out at pH 7 and in the presence of appropriate amounts of EDTA as masking agent.

In this study, Tetryl interaction with single walled carbon nanotube was evaluated by density functional theory. For this purpose, the structures of the investigated compounds were optimized geometrically. Then, IR, frontier molecular orbital FMO and Natural bond orbital NBO computations were performed on them. The obtained results such as thermodynamic parameters like adsorption enthalpy changes ΔHad, Gibbs free energy variations ΔGad, thermodynamic equilibrium constant Kth revealed that tetryl interaction with carbon nanotube is exothermic, spontaneous and non-equilibrium. The effect of temperature on the adsorption process was also checked out and the results indicated the efficiency of adsorption process has increased by decreasing the temperature. The values of specific heat capacity CV substantiated that the heat sensitivity of tetryl has declined after its interaction with carbon nanotube. The results of frontier molecular orbital parameters showed the applicability of carbon nanotube for construction of new electrochemical sensors for detection of tetryl because the bandgap increased sharply when tetryl was adsorbed on the surface of carbon nanotube therefore, the resulting decline in the electrical conductivity can be used as a signal for detection of tetryl.

The detection of ethanol is based on the signal produced by nicotinamide adenine dinucleotide NAD, the product of the enzymatic reaction. Anthraquinone 2-carboxylic acid AQ as electron shuttling mediator was attached to NAD of alcohol dehydrogenase ADH to facilitate the electron transferring. Also, multiwalled carbon nanotubes MWCNTs for the high electrical conductivity, MWCNTs capability for functionalization and large surface were used as carriers for protein immobilization. Based on, MWCNTs at first were functionalized with carboxyl groups by oxidation with nitric acid 65 and ultrasonic dispersion. FTIR and SEM studies confirm the formation of carboxylic acid functionalized MWCNTs. The electrocatalytic activities of AQ and MWCNT improve towards the reduction of NAD. Covalent attachment of carboxylic acid of anthraquinone molecules and carboxylic acid functionalized MWCNTs to the amine group of NAD established. The CNT/AQ-NAD/ADH electrode was applied for amperommetric sensing of ethanol in the linear concentration range from 3.34 up to 22.8 µM at optimum conditions and specifically, the attached ADH on NAD-AQ/CNT/GC electrode showed quasi-reversible cyclic voltammogram with the formal potential of -0.562 and -0.488V. The CNT/AQ-NAD electrode represents a general approach to the development of dehydrogenases-based electrochemical biosensors.

In this study the cobalt ferrite nanoparticles synthesized via a sol-gel green auto-combustion method using kiwi fruit extract. Then cobalt ferrite was added to polystyrene PS polymer. The X-ray diffraction pattern of CoFe2O4 nanoparticles shown pure cubic phase and the crystallite size was calculated by Debye -Scherrer’s formula about 45 nm. The SEM images of cobalt ferrite illustrated cubic shape. The FESEM image of polystyrene/ cobalt ferrite nanocomposites had been shown nanoparticles being inside polymer matrix. X-ray mapping provides presence all elements distributed homogeneously in polymer. The FT-IR spectrum of the nanocomposites exhibits all cobalt ferrite and polystyrene atomic bond peaks. Hysteresis loops of cobalt ferrite nanoparticles and magnetic/polymer nanocomposites shown cobalt ferrite nanoparticles have more saturated magnetization and less coercivity than nanocomposites. The cobalt ferrite effect on the flame retardancy polystyrene was investigated applying UL-94 test. The pure polystyrene had V-0 classification and polystyrene/ cobalt ferrite nanocomposites have HB category. The mechanical properties of samples pure polystyrene and polystyrene/ cobalt ferrite nanocomposites have been studied by tensile testing machine.The stress-strain curves for these two samples shown addition nanoparticles to polymer increase the tensile strength and decrease the elongation of sample.

The aim of this study is simulating a system of water-GNPs and investigating nanofluid specifications and heat transfer proses from nanoparticles to solution. The initial condition is coordinated by the use of Packmol and Moltemplate codes, General equations were applied by the use of LAMMPS open-source code. Post-Processing methods were down by the use of MATLAB, VMD and Python software. Heat transfer proses from GNPs to solution investigated by the use of SNEMD method. According to the result, adding GNPs reduces the interface layer and increases surface tension value. The rate of surface tension and mole fraction enhancement with the bigger GNPs is greater than the system with smaller GNPs. In cooling proses, the heat transfers fewer than 5ps in 2mm and heat conduction in the first layer of water is 50 greater than other parts of the fluid. It can be concluded that, when the molecular density increases near the surface of Nanofluid, and reduction of surface tension, Nanofluids dispersion with organic fluid is less possible. This phenomenon helps to increase the diagnosis and treatment efficiency. Therefore, by the use of GNPs in Hyperthermia, Increasing temperature has higher impacts on cancer cells closer to GNPs than far normal cells.

Thioglycolic acid TGA capped CdTe quantum dots QDs of different sizes 2.7, 3 and 3.4 nm were prepared by aqueous method. Then, the fresh QDs were illuminated ultraviolet light. There by effect of lighting on optical properties of QDs were investigated systematically. It was revealed that emission spectra of QDs took a sharp change after UV illumination. ultraviolet UV light. There by effect of lighting on optical properties of QDs were investigated systematically. The results show that the magnitude of changes in the fluorescence intensity and peak position varies with the particle sizes. The fluorescence peaks maximum intensity of quantum dots with a size of 3.4 nm; 5.2 times increases after 102 h of UV illumination. Whereas QDs with a size of 3 nm, peak maximum intensity considerably increases 31 times after 88 h illumination. In three instances, the fluorescence peak position is shifted toward the lower wavelengths. As size of QDs decreases, the emission peak position shifts more towards lower wavelengths under irradiation is greater. In this paper, the mechanism of these changes of the optical properties of the QDs is studied.