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حرية الوصول المقاله
1 - Photoluminescence study of Au-Ag bimetallic nanoparticles supported on mesoporous silica SBA-15
Saba Estakhri Elham Darabi Behrouz Akbari Adergani Seyed ElahiBimetallic Au-Ag nanoparticles with homogeneous dispersion in amine-modified SBA-15 mesoporous silica channels were successfully synthesized by the post-modification method. The obtained nanocomposites with different component ratios were studied by structural, Physico- أکثرBimetallic Au-Ag nanoparticles with homogeneous dispersion in amine-modified SBA-15 mesoporous silica channels were successfully synthesized by the post-modification method. The obtained nanocomposites with different component ratios were studied by structural, Physico-chemical, and optical analysis. The structural and Physico-chemical properties were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and nitrogen adsorption-desorption isotherm measurement (BET). The optical properties were characterized by photoluminescence (PL) and UV-Vis spectroscopy. The photoluminescence and absorption spectra were strongly affected by the change in the compositional ratio of gold to silver nanoparticles due to the interactions of Au-Ag nanoparticles, the configuration of conduction electrons and their plasmonic properties. A significant enhancement was observed in the photoluminescence spectrum in the long-wavelength red emission at 640 nm for a one-to-one composition ratio of Au/Ag/SBA-15 nanocomposite. Since the light emission of most microorganisms is in the visible range, the nanocomposite produced can be proposed for applications in biosensor technology. تفاصيل المقالة -
حرية الوصول المقاله
2 - Dielectric, electro-optical and spectroscopic properties of silver doped zinc oxide-ferroelectric liquid crystal composite system
Kaushlendra Agrahari Sanjeev Trivedi Ram Awasthi Vivek Nautiyal Rakesh Sonker Rajiv ManoharIn the present study, silver doped zinc oxide nanoparticles (NPs) have been added in the pristine ferroelectric liquid crystal (FLC). The dielectric, electro-optical and spectroscopic properties was investigated of the pristine FLC and FLC-NPs composite system. The disp أکثرIn the present study, silver doped zinc oxide nanoparticles (NPs) have been added in the pristine ferroelectric liquid crystal (FLC). The dielectric, electro-optical and spectroscopic properties was investigated of the pristine FLC and FLC-NPs composite system. The dispersion of NPs into the pristine FLC material sturdily influences the various properties of composite system. Due to dispersion of NPs, a rapid increment in the dielectric permittivity and faster switching was observed for the FLC-NPs composite system. Absorbance of the UV light got diminished in the presence of silver doped zinc oxide NPs. Photoluminescence emission of the pristine FLC material has been quenched after the addition of NPs and a red shift was also detected. The possible applications of this investigation have been suggested in the letter. تفاصيل المقالة -
حرية الوصول المقاله
3 - Estimation of lattice strain in ZnO nanoparticles: X-ray peak profile analysis
P. Bindu Sabu ThomasAbstractZnO nanoparticles were synthesized from chitosan and zinc chloride by a precipitation method. The synthesized ZnO nanoparticles were characterized by Fourier transform infrared spectroscopy, X-ray diffraction peak profile analysis, Scanning electron microscopy, أکثرAbstractZnO nanoparticles were synthesized from chitosan and zinc chloride by a precipitation method. The synthesized ZnO nanoparticles were characterized by Fourier transform infrared spectroscopy, X-ray diffraction peak profile analysis, Scanning electron microscopy, Transmission electron microscopy and Photoluminescence. The X-ray diffraction results revealed that the sample was crystalline with a hexagonal wurtzite phase. We have investigated the crystallite development in ZnO nanoparticles by X-ray peak profile analysis. The Williamson–Hall analysis and size–strain plot were used to study the individual contributions of crystallite sizes and lattice strain ϵ on the peak broadening of ZnO nanoparticles. The parameters including strain, stress and energy density value were calculated for all the reflection peaks of X-ray diffraction corresponding to wurtzite hexagonal phase of ZnO lying in the range 20°–80° using the modified form of Williamson–Hall plots and size–strain plot. The results showed that the crystallite size estimated from Scherrer’s formula, Williamson–Hall plots and size–strain plot, and the particle size estimated from Transmission electron microscopy analysis are very much inter-correlated. Both methods, the X-ray diffraction and Transmission electron microscopy, provide less deviation between crystallite size and particle size in the present case. تفاصيل المقالة -
حرية الوصول المقاله
4 - Effect of ion trapping behavior of TiO2 nanoparticles on different parameters of weakly polar nematic liquid crystal
Geeta Yadav Rohit Katiyar Govind Pathak Rajiv ManoharAbstractIn the present investigation, TiO2-doped weakly polar nematic liquid crystal (NLC) has been studied. This study mainly focuses on dielectric, electro-optical and optical properties of pure NLC and doped systems. Variation in different parameters like dielectric أکثرAbstractIn the present investigation, TiO2-doped weakly polar nematic liquid crystal (NLC) has been studied. This study mainly focuses on dielectric, electro-optical and optical properties of pure NLC and doped systems. Variation in different parameters like dielectric permittivity, dielectric loss, dielectric anisotropy and conductivity has been noticed. Permittivity of the doped system is almost the same as undoped system. With doping concentration, the ionic contribution to the dielectric loss as observed in low-frequency region has been suppressed and the shift in relaxation frequency toward higher frequency side has also been observed. The electrical conductivity and threshold voltage have been decreased with increasing concentration of nanoparticles (NPs). The continuous increase in dielectric anisotropy with increasing the concentration of NPs has also been observed. These results have been attributed to the trapping capability of free ions by TiO2 NPs. Further, we focused on the study of photoluminescence (PL), UV absorbance and Fourier transformed infrared spectroscopy (FTIR) of pure and doped systems. The continuous increase in PL intensity without any shift in emission peak has been observed for doped systems. Enhancement in UV absorbance with increasing concentration of NPs has also been observed. The effect of NPs doping on molecular dynamics of NLC can be clearly seen by FTIR study. The results suggest that the TiO2 NP-doped weakly polar NLC can have significant improved dielectric, electro-optical and optical properties. This makes the weakly polar NLC to be a potential candidate for many applications. تفاصيل المقالة -
حرية الوصول المقاله
5 - Synthesis, structural and optical properties of pure ZnO and Co doped ZnO nanoparticles prepared by the co-precipitation method
P. Geetha Devi A. Sakthi VeluAbstractPure ZnO and Cobalt (Co) doped ZnO nanoparticles (NPs) were synthesized by the co-precipitation method. The synthesized nanoparticles retained the wurtzite hexagonal structure, which was confirmed by X-ray diffraction studies. From FESEM studies, ZnO and Co dope أکثرAbstractPure ZnO and Cobalt (Co) doped ZnO nanoparticles (NPs) were synthesized by the co-precipitation method. The synthesized nanoparticles retained the wurtzite hexagonal structure, which was confirmed by X-ray diffraction studies. From FESEM studies, ZnO and Co doped ZnO NPs showed Spherical and nanorod mixed phase and Spherical like morphology, respectively. The amount of dopant (Co2+) incorporated into ZnO sample was determined by EDAX. The FT-IR spectra confirmed the Zn–O stretching bands at 438 and 427 cm−1 for ZnO and Co doped ZnO NPs. From the UV–VIS spectroscopic measurements, the excitonic pecks were found around 376 and 370 nm for the respective samples. The photoluminescence measurements revealed that the broad emission was composed of seven different bands due to zinc vacancies, oxygen vacancies and surface defects. The dynamic light scattering (DLS) and Zeta potential measurements were used to find out the size and surface charges. تفاصيل المقالة -
حرية الوصول المقاله
6 - Effect of ZnS shell on optical properties of Ni-doped ZnSe nanocrystals
Ehsan Soheyli Gholamreza Nabiyouni Reza SahraeiThe present paper aims to suggest a simple/fast route for direct preparation of the Ni-doped ZnSe/ZnS core/shell NCs in aqueous solution. Using XRD measurement, the zinc blend structure and sub-5 nm average size of the NCs was proved. The FT-IR spectrum also showed the أکثرThe present paper aims to suggest a simple/fast route for direct preparation of the Ni-doped ZnSe/ZnS core/shell NCs in aqueous solution. Using XRD measurement, the zinc blend structure and sub-5 nm average size of the NCs was proved. The FT-IR spectrum also showed the passivation of the NCs surface by means of the deprotonated thiol terminals of the NAC molecules. The intensity of the dopant-related emission at about 476 nm in Ni:ZnSe doped NCs was found to experience more than four times enhancement by utilization of the extra ZnS shell. It was also observed that the increasing of the shell overcoating time from 1 to 3 h, has effective role on better passivation of the surface of the NCs and increasing of the emission intensity تفاصيل المقالة -
حرية الوصول المقاله
7 - Preparation of polyethersulfone membrane coated by a nanocomposite structure
Farhad HeidaryNanocomposite membranes were prepared by coating a porous Polyethersulfone (PES) support containing 8-hydroxyquinoline (as complexing agent) with poly (vinyl alcohol) (PVA)/Fe3O4 nanocomposite solution. The prepared membranes were applied for removal of Zn(II) ions from أکثرNanocomposite membranes were prepared by coating a porous Polyethersulfone (PES) support containing 8-hydroxyquinoline (as complexing agent) with poly (vinyl alcohol) (PVA)/Fe3O4 nanocomposite solution. The prepared membranes were applied for removal of Zn(II) ions from water. The effect of membrane modification on the membranes performance for removal of metal ions was investigated. The results indicated that presence of ligand and Fe3O4 nanoparticles in the membrane structure enhanced the ions rejection. The prepared samples were characterized by scanning electron microscopy. SEM images indicated appropriate distribution of nanoparticles in the polymeric matrix. تفاصيل المقالة -
حرية الوصول المقاله
8 - The liquid environment effect on photoluminescence properties of carbon nanoparticles prepared by laser ablation method in liquids with possible biocompatibility applications
Rasoul Malekfar Samad Moemen Bellah Fatemeh KazemizadehFluorescent carbon nanoparticles (CNPs) were prepared by nanosecond laser ablation of graphite powder in liquid. The effect of the liquid medium on photoluminescence (PL) efficiency and wavelength range were studied experimentally. Four solvents, polyethylene glycol, di أکثرFluorescent carbon nanoparticles (CNPs) were prepared by nanosecond laser ablation of graphite powder in liquid. The effect of the liquid medium on photoluminescence (PL) efficiency and wavelength range were studied experimentally. Four solvents, polyethylene glycol, diethanolamine, diethylamine, and ethylenediamine were used as liquid platforms in the synthesis process. Analyzing the chemical components and optical spectral characterization of CNPs was carried out by attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy and photoluminescence (PL) spectroscopy, respectively. Moreover, the size of CNPs was estimated by using dynamic light scattering (DLS) measurements. Liquid components are determined to be a key factor affecting PL properties and nanoparticle size. The results are valuable in practical applications. تفاصيل المقالة -
حرية الوصول المقاله
9 - Evaluation of heat temperatures on the structure of nano-rod
hassan GHEISARIIn this project, the TiO2 nano-rods were synthesized from P25 TiO2 nanoparticles by hydrothermal method in 20 M NaOH solution. The effects of annealing temperatures on produced nanorods were investigated by scanning electron microscopy (SEM) X-ray diffraction (XRD) and أکثرIn this project, the TiO2 nano-rods were synthesized from P25 TiO2 nanoparticles by hydrothermal method in 20 M NaOH solution. The effects of annealing temperatures on produced nanorods were investigated by scanning electron microscopy (SEM) X-ray diffraction (XRD) and photoluminescence (PL) spectroscopy. Diameter growth and changes of surface oxygen defects of synthesized Nano rods are studied with increasing annealing temperatures. Also, with Increase of annealing temperature over 300 °C there is no effect on the size of produced nano-rods, but due to reducing of the surface charge causes the more compact products. In summation, the effects of post heat treatment temperatures were in detail investigated by SEM, XRD and PL spectroscopy. The obtained results were shown that the increasing of annealing temperature until 300 °C causes increase of thicknesses of prepared nanorods by hydrothermal method. Increase of annealing temperature over 300 °C has no effect on the size of produced nanorods, but due to reducing of the surface charge causes the more compact products. In addition, the surface defects of synthesized 1D TiO2 were decreased because of increase of annealing temperatures, but we should note that at higher tempera tures (over 500 °C) the TiO2 phase may be converted from anatase to rutile. تفاصيل المقالة -
حرية الوصول المقاله
10 - Evaluation of heat temperatures on the structure of nano-rod
Hassan GHEISARIIn this project, the TiO2 nanorods were synthesized from P25 TiO2 nanoparticlesby the hydrothermal method in 20 M NaOH solution. The effects of annealingtemperatures on produced nanorods were investigated by scanning electronmicroscopy (SEM) X-ray diffraction (XRD) and أکثرIn this project, the TiO2 nanorods were synthesized from P25 TiO2 nanoparticlesby the hydrothermal method in 20 M NaOH solution. The effects of annealingtemperatures on produced nanorods were investigated by scanning electronmicroscopy (SEM) X-ray diffraction (XRD) and photoluminescence (PL)spectroscopy. An increase of annealing temperature over 300 °C has no effect on thesize of produced nanorods, but due to reduction of the surface charge causes themore compact products. In addition, the surface defects of synthesized 1D TiO2were decreased because of an increase in annealing temperatures, but we shouldnote that at higher temperatures (over 500 °C) the TiO2 phase may be convertedfrom anatase to rutile.Diameter growth and changes of surface oxygen defects ofsynthesized Nanorods are studied with increasing annealing temperatures. Also,with an increase in annealing temperature over 300 °C, there is no effect on the sizeof produced nano-rods, but due to reduction of the surface charge causes themore compact products. تفاصيل المقالة
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