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Nanoscience and Nanotechnology - Volume:13 Issue: 4, Autumn 2017

International Journal Of Nanoscience and Nanotechnology
Volume:13 Issue: 4, Autumn 2017

  • تاریخ انتشار: 1396/09/12
  • تعداد عناوین: 8
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  • M. Alavi, S. Shojaei * Pages 289-298
    Here, we report a theoretical detailed study of Vacuum Rabi Splitting (VRS) in the system of Nitride Single Quantum Well (SQW) within a semiconductor microcavity. Distributed Bragg Reflectors (DBRs) containing ZnTe/ZnSe multilayers including GaAs microcavity and ( SQW at the center of microcavity, has been considered. Upper and lower exciton-polariton branches obtained through angle-dependent reflectance calculations performed by the means of Transfer Matrix Method (TMM). Large value of 20.1(23.4) meV VRS is obtained by changing the Aluminum (Indium) molar fraction at the Room Temperature (RT) for TM mode. Our findings show that SQW are better candidates rather than to achieve larger values of VRS. Our calculations pave the way towards modeling of polaritonic devices.
    Keywords: Vacuum Rabi Splitting, Exciton binding energy, Nitride semiconductors
  • A. Arab *, F. Gobal Pages 299-306
    Adsorption of OH on the PdxCu3-x(x=0-3) small clusters is investigated by density functional theory calculations. It is found that OH adsorbs in three possible modes including on top, bridge and hollow sites while the structures where OH bridges between two atoms are the most stable structures. The Pd-Pd, Pd-Cu and Cu-Cu equilibrium distances for most of the systems increase after OH adsorption and variations are higher for Pd-Pd equilibrium distances compared to Pd-Cu and Cu-Cu equilibrium distances. Adsorption of OH on Cu atom is more favored than on Pd atom. With increasing copper content of the nano-clusters the adsorption energy of OH drops to a minimum and increases with further increasing in copper content.
    Keywords: OH adsorption, Pd-Cu nano clusters, DFT
  • M. Khaleghi *, M. Madani, P. Parsia Pages 307-313
    Background
    Biosynthesis of is one of the safe methods in nanoparticles (NP) production where local bacteria of every region can be applied for its better functionality. Among these nanoparticles, the silver nanoparticles (SNP) with high applicability due to their antimicrobial characteristic are the most common.

    Methods
    In the study, the soil samples are collected from metal mines of Kerman province and their bacteria content is screened and purified. Then, the SNP biosynthesis test is run on Biomass and bacterial supernatant. The parameters here consist of two Molarity of silver nitrate (10-2 and 10-3), different temperature effect on biosynthesis of SNP, and light/dark conditions which are assessed here to optimize SNP production rate, and the results are confirmed.

    Results
    From the bacterial isolations, the Pseudomonas Iranica NCBI: KF742672, was able to produce SNP from silver nitrate salt of 20-80 nm at 30°C, In dark condition and 10-2 Molarity.

    Conclusions
    Bacteria can be consumed as a safe and clean element to produce NP, which is in wide use due to new characterizations that are revealed through studies, of course with the safety factor is of major concern.
    Keywords: Biosynthesis, Silver nanoparticles, Mine soils, XRD, TEM
  • H. Narayan*, H. Alemu Pages 315-325
    TiO2 based nanocomposites (NCs) were synthesized using the co-precipitation/hydrolysis (CPH) method. The composition of the first set (TZF) and the second set (TY) of NCs were: TiO2.[ZnFe2O4]x (with x = 0.1 to 0.5), and TiO2.[Y2O3]x (with x = 0.1 to 0.5), respectively. NCs with average crystallite size of 29 nm were produced whit co-doped Zn2ﱗ ions into TiO2. This size was 17 nm when Y3 ions were doped. Characterization of all samples were done by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD) and particle size analyzer. Visible light photocatalytic degradation of the dye Congo red (CR) was investigated in the presence of each of the samples. In comparison with pure TiO2, enhanced photocatalytic activity was recorded with NCs. The NCs with x = 0.2 and x = 0.1 of TY and TZF sets, respectively, showed maximum photocatalysis both in terms of the apparent rate constant, as well as the percent degradation observed after 180 minutes. It was noted that enhanced photodegradation is directly related to the reduced particle size of the composites which implies that, photosensitization is the dominant process. The better photocatalytic activity observed with TY in comparison to with TZF NCs was attributed to the effective suppression of the e–/h recombination because of the trapping of photo-generated electron by the Y3 ions.
    Keywords: Titanium dioxide, Nanocomposite, Photocatalysis
  • R. Sabbaghi-Nadooshan *, M. Siasar Karbasaki Pages 327-333
    The current study designed and simulated graphene nanosensors for detection of GLY120 tumor-associated carbohydrate antigens. Graphene is a two-dimensional nanosheet that offers a high surface-to-volume ratio and high mobility which increases its sensitivity as a graphene sensor over that of other nanoparticles. The current study simulated graphene sensors with and without GLY120 tumor markers and compared the two conditions. GLY120 tumor-associated antigens are present in blood and breast tissue. When GLY120 was attached to the graphene sheet, the Fermi energy, total energy, potential energy, band structure energy and electron kinetic energy of the nanosheet changed. It was then possible to determine the difference in the curves in each state.
    Keywords: Diagnosis, Cancer, GLY120 Antigen, Graphene
  • R. Ansari *, M. Hassanzadeh, F. Ostovar Pages 335-345
    In the present study, CeO2/Fe2O3 nanocomposite was prepared by co-precipitation method and its application was investigated for arsenic removal from water. Characterization of the nano sized adsorbent particles was carried out using SEM and XRD techniques. Systemic adsorption experiments were performed in batch systems and the optimum conditions were obtained. The effects of pH, contact time, adsorbent mass, temperature, ionic strength and initial concentration of arsenic were investigated on kinetics and equilibrium of the adsorption. Thermodynamic parameters and adsorption kinetics were studied in detailed to know the nature and mechanism of adsorption. Kinetic studies showed that the adsorption process followed pseudo second order kinetic model. The thermodynamic parameters such as ΔG⁰, ΔS⁰ and ΔH⁰ were calculated, and it was found that the reaction was spontaneous and exothermic in nature. Adsorption equilibrium was studied using Langmuir and Freundlich isotherm models. It was observed that the investigated adsorption process followed Freundlich isotherm. Adsorption capacity (q0) calculated from Langmuir isotherm was found to be 8.260 mg.g-1.The results showed that CeO2/Fe2O3 nanocomposite particles can be effectively used for the removal of As(III) ions from aqueous solutions.
    Keywords: Adsorption, Arsenic(III) removal, Cerium(IV) oxide, Iron(III) oxide, Nanocomposite
  • N. Nami *, S. Lale Mohammadi Pages 347-357
    One-pot reaction of aldehydes with thiosemicarbazide was performed using NaBH4 and Fe3O4 magnetic nanoparticles (MNPs). The reaction mixture of thiosemicarbazide and carbonyl compounds was stirred under reflux condition in the present of Fe3O4 MNPs and NaBH4.The optimum amount of Fe3O4 MNPs was 5 mol% in ethanol. The precipitate was appeared immediately to obtain 1,2,4-triazolidine. The reflux continued 20 min after addition of NaBH4 to complete the reaction. 1,2,4-triazolidines were obtained in good to excellent yields. All products were identified by GC-Mass, NMR, FT-IR spectra and physical data with those of authentic samples. The magnetically recoverable iron oxide nanoparticles are found to be efficient for synthesis of 1,2,4-triazolidine derivatives. The Fe3O4 MNPs were simply recovered by external magnetic field and exhibited exceptionally high catalytic activity in green chemistry and enhanced reaction speed without pollution. Fe3O4 MNPs could be successfully recovered and reuse. This method is easier and less expensive than the other methods.
    Keywords: Fe3O4 magnetic nanoparticles, Thiosemicarbazone, 1, 2, 4-triazolidine, NaBH4
  • Z. Shadrokh *, A. Yazdani, H. Eshghi Pages 359-366
    A simple low-cost solvothermal method was applied to synthesize hexagonal wurtzite Cu2ZnSnS4 (CZTS) nanoparticles with different morphologies using Polyvinylpyrrolidone (PVP) as a capping ligand and copper and zinc acetate salts at 180 and 220 ℃. The resulting sphere-like and flower-like nanoparticles synthesized at 180 and 220℃, respectively, indicated thecalculated optical band gaps of 1.45 and 1.28 eV, respectively. Where both samples indicated the metastable wurtzite phase. The main Raman peaks were observed at 333 and 371 cm-1, was indicating the wurtzite phase of CZTS nanocrystals. The phase of the wurtzite CZTS nanoparticles was successfully controlled by using zinc acetate salt, which affected the reaction rate between Zn and S sources. In addition, reaction temperature was found as an effective factor on the morphology, elemental ratio, reaction kinetic, crystallinity, and size of the CZTS nanoparticles. Photoresponse of the CZTS thin films were confirmed by I-V measurements under dark and light illumination. All these results imply the potential of these nanoparticles for solar cell applications.
    Keywords: Semiconductors, Wurtzite CZTS nanoparticles, Solvothermal method, Raman spectroscopy