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Synthesize and Characterization of 2D WS2 Nano-layers for Next Generation Optoelectronic Devices
, M.Sc. Thesis Sharif University of Technology ; Simchi, Abdolreza (Supervisor)
Abstract
Transition Metal Dichalcogenids (TMD) are types of 2D materials that exibit wide range of electronic, optical, mechanical, chemical, and thermal properties. These materials with MX2 general formula, have atract attentions with respect to their unusual properties because of their very limited dimensions. Their tunable properties and materials availibility make them attractive for wide range of applications. In recent years, chemical vapor deposition (CVD) methods are promising in preparing high quality TMD with scalable size, controllable thickness, and very excellent electronic properties. Also, chalenges are remaining in synthesis and transfering of TMD are difficulty for most of...
ZnO Coating, Containing SiO2 Nano Particles, Prepared by Sol-gel Process and Investigation of Surface Properties
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor) ; Askari, Masoud (Co-Advisor)
Abstract
Zinc oxide thin films due to special specification and properties have variable application in different industries. Recently because of wide application of zinc oxide doped SiO2 in optoelectronics and sensors, lots of investigation have been focus on it. Meanwhile due to the SiO2 hydrophilic properties, doping of ZnO with SiO2 can improve self-cleaning properties zinc oxide membrane.It this project zinc oxide and ZnO doped SiO2 thin films with different composition were made by sol-gel and dip-coating process used for coating of mentioned sol over the quartz surface(15*25 mm). At first point different sol with different components was mixed with each other to make composite films but due to...
Synthesis of NiO Nano-Powder by TSSC Process and NiO Nano-Layers synthesis by TSCD Process and Kinetics Modeling of Nickel Oxide Nano-Layer Growth by Diffuse-Interface Model
, M.Sc. Thesis Sharif University of Technology ; Sadrnezhad, Khatiboleslam (Supervisor)
Abstract
Nickel oxide is used in the manufacture of ceramic, magnetic materials, battery cathodes, electrochromic films, heterogeneous catalytic materials and gas sensors. NiO nano-powder can be produced with many different methods. The synthesis of NiO nanopowder has been carried out via solochemical processing from an aqueous solution of a Ni containing complex in this research. Another name for this method is two-stage solochemical (TSSC) method. This is the newest economic method for synthesis of NiO nanopowder. NiCl2 anhydrous and NH3-H2O used as the raw materials and H2O used as solvent. The results obtained from XRD and TEM show that the nanoparticles have cubic crystal structure and the mean...
Synthesis and Characterization of Structural and Photocatalytic Properties of Ag-TiO2 Nano-Coatings
, M.Sc. Thesis Sharif University of Technology ; Taghavinia, Nima (Supervisor)
Abstract
Titanium dioxide has covered a wide range of applications as a semiconductor photocatalyst. TiO2 is an indirect, 3.2 eV band gap semiconductor which can be stimulated using UV light. Improving the quick electron-hole recombination rate, we can enhance the photocatalytic efficiency of this semiconductor. One of the approaches in hand is to use noble metals in connection to TiO2. Among noble metals, due to its plasmonic and anti-bacterial properties and ease of preparation, silver would serve as a perfect candidate. The mechanism for photocatalytic enhancement in Ag-TiO2 structures lies behind the fact that silver can trap the photogenerated electron of TiO2 and inhibit the electron-hole...
Molecularly imprinted polydopamine nano-layer on the pore surface of porous particles for protein capture in HPLC column
, Article Journal of Colloid and Interface Science ; Volume 404 , 2013 , Pages 117-126 ; 00219797 (ISSN) ; Shojaei, A ; Abdekhodaie, M. J ; Sellergren, B ; Sharif University of Technology
2013
Abstract
Bio-inspired Human Serum Albumin (HSA) imprinted polydopamine nano-layer was produced through oxidative polymerization of dopamine on the pore surface of HSA modified porous silica particles. The coating thickness was controlled by the reaction time and thereby varied within 0-12. nm. The samples were characterized by elemental analysis, FT-IR, DSC, SEM, TEM, TGA, physisorption and thermoporometry. The characterization confirmed the success of evolution and deposition of polydopamine layer on the silica pore surface. Batch rebinding experiment showed that the molecularly imprinted polymer (MIP) with 8.7. nm coating thickness, in comparison with the thinner and thicker coatings, displays the...
Photo-destruction of cancer cells by NIR irradiation and graphene nano-sheets
, Article Technical Proceedings of the 2011 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2011, 13 June 2011 through 16 June 2011, Boston, MA ; Volume 3 , 2011 , Pages 236-239 ; 9781439871386 (ISBN) ; Mohajerzadeh, S ; Janmaleki, M ; Akhavan, O ; Azimi, S ; Clean Technology and Sustainable Industries Organization (CTSI); European Patent Office; Greenberg Traurig; Innovation and Materials Science Institute; Jackson Walker L.L.P ; Sharif University of Technology
2011
Abstract
The photo-thermal therapy using nano-materials has attracted great attention as an efficient strategy for the next generation of cancer treatments. Recently, photo-thermal therapy based on nano-materials that can be activated by a skin-penetrating NIR (Near Infra Red) irradiation has been suggested as a noninvasive, harmless, and highly efficient therapeutic technique. Graphene nano-layers synthesized by a bio-compatible method, with reduced toxicity, will be a suitable candidate for the photo-thermal therapeutic agent. A significant amount of heat is generated upon excitation with near-infrared light (NIR, 700-1100nm) which is transparent to biological species including skins. In this...
A comparative study on photoelectrochemical activity of ZnO/TiO2 and TiO2/ZnO nanolayer systems under visible irradiation
, Article Solar Energy ; Volume 85, Issue 9 , 2011 , Pages 1972-1978 ; 0038092X (ISSN) ; Yousefi, M ; Moshfegh, A. Z ; Sharif University of Technology
Abstract
TiO2/ZnO and ZnO/TiO2 nanolayer thin films were synthesized using sol-gel method. Optical analysis revealed high transmittance of the films in the visible range with almost the same bandgap energy for the both systems. XPS technique shows stoichiometric formation of TiO2 and ZnO on the surface of TiO2/ZnO and ZnO/TiO2 layers, respectively. According to AFM observations and its data analysis, the TiO2/ZnO films exhibited a higher surface roughness and more effective interfaces with electrolyte during redox reactions. Based on photoelectrochemical measurements, TiO2/ZnO nanolayer photoanode possesses a lower charge transfer resistance and higher transient time for charge carriers (e- and h+)...
Photocatalytic property of Fe2O3 nanograin chains coated by TiO2 nanolayer in visible light irradiation
, Article Applied Catalysis A: General ; Volume 369, Issue 1-2 , 2009 , Pages 77-82 ; 0926860X (ISSN) ; Azimirad, R ; Sharif University of Technology
2009
Abstract
The visible light photocatalytic activity of α-Fe2O3 nanograin chains coated by anatase TiO2 nanolayer, as a photocatalyst thin film for inactivation of Escherichia coli bacteria, was investigated for the solutions containing 106 colony forming units per milliliter of the bacteria, without and with H2O2 (60 μM). Thin films of the α-Fe2O3 nanograins with the grain size of 40-280 nm were grown on glass substrates by post-annealing of the thermal evaporated Fe3O4 thin films at 400 °C in air. The TiO2 layer with thickness of about 20 nm was coated on the nanograins by dipping the Fe2O3 thin films in a prepared TiO2 sol and re-annealing them at 400 °C in air. The antibacterial activity of the...
Kinetics of TSCD zinc oxide nano-layer growth by modified diffuse-interface model
, Article Ceramics International ; Volume 33, Issue 8 , December , 2007 , Pages 1409-1417 ; 02728842 (ISSN) ; Vaezi, M. R ; Sharif University of Technology
2007
Abstract
Deposition of zinc oxide films from aqueous solutions containing complex Zn2+ ions on soda-lime substrates were studied by two-stage chemical deposition (TSCD) process. It was shown that the film thickness can be controlled by the number of dipping stages. Nano-layers were produced with less than nine times dipping stages. Greater dipping numbers resulted in film thickness exceeding 100 nm. The growth rate obeyed double-stage zeroth order with respect to the concentration and first order with respect to the temperature. This rate was proportional to the difference between the temperature of the hot water and the substrate. Overall activation energy of 17.20 ± 0.42 kJ mol-1 and frequency...
Enhanced local viscosity around colloidal nanoparticles probed by equilibrium molecular dynamics simulations
, Article Journal of Chemical Physics ; Volume 155, Issue 17 , 2021 ; 00219606 (ISSN) ; Saidi, M. H ; Joly, L ; Merabia, S ; Rajabpour, A ; Sharif University of Technology
American Institute of Physics Inc
2021
Abstract
Nanofluids - dispersions of nanometer-sized particles in a liquid medium - have been proposed for a wide variety of thermal management applications. It is known that a solid-like nanolayer of liquid of typical thicknesses of 0.5-1 nm surrounding the colloidal nanoparticles can act as a thermal bridge between the nanoparticle and the bulk liquid. Yet, its effect on the nanofluid viscosity has not been elucidated so far. In this article, we compute the local viscosity of the nanolayer using equilibrium molecular dynamics based on the Green-Kubo formula. We first assess the validity of the method to predict the viscosity locally. We apply this methodology to the calculation of the local...
Plasma-enhanced chemical vapor deposition for fabrication of yolk-shell SnO2@Void@C nanowires, as an efficient carbon coating technique for improving lithium-ion battery performance
, Article Materials Science in Semiconductor Processing ; Volume 149 , 2022 ; 13698001 (ISSN) ; Mousavi, M. R ; Yasoubi, M ; Sanaee, Z ; Ghasemi, S ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
This manuscript describes the implementation of plasma-enhanced chemical vapor deposition (DC-PECVD) and vapor-liquid-solid (VLS) techniques to fabricate a yolk-shell SnO2@Void@C nanowire (NW) structure. SnO2 nanowires have been synthesized on the stainless steel mesh substrate through the VLS method. The PECVD-assisted growth of carbon nanolayer on the SnO2 and SiO2 coated SnO2 NWs has been performed to fabricate SnO2@C core-shell and SnO2@SiO2@C yolk-shell structures, respectively. A consequent silica etching process converted the SnO2@SiO2@C into SnO2@Void@C structure. The electrochemical performance of bare SnO2 NWs, SnO2 NWs @ C, and SnO2 @Void @ C coaxial NWs structures have been...
A new approach for simultaneously improved osseointegration and antibacterial activity by electrochemical deposition of graphene nanolayers over titania nanotubes
, Article Applied Surface Science ; Volume 580 , 2022 ; 01694332 (ISSN) ; Bagheri, R ; Vossoughi, M ; khafaji, M ; Asadian, E ; Ahmadi Seyedkhani, S ; Samadikuchaksaraei, A ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Simultaneous enhancement of osseointegration and bacterial infection prohibition through surface modifications is a challenging but promising approach to achieve durable implantation. To that end, we present a multifunctional surface coating composed of graphene nanolayers and hierarchical well-aligned TiO2 nanotubes with a nanoporous top layer (cRTNT). FESEM studies reveal tunable increasing island morphologies of graphene nanolayers (G) on cRTNT by a cyclic voltammetry process. XPS analysis shows that the enhanced interface chemistry is due to TiO2-carbon bonding. The roughness of the sample containing a medium amount of graphene, cRTNT-75%GO, was calculated ∼289 nm, which was 543% higher...