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Solution-processed perovskite thin-films: The journey from lab: The large-scale solar cells
, Article Energy and Environmental Science ; Volume 14, Issue 11 , 2021 , Pages 5690-5722 ; 17545692 (ISSN) ; Byranvand, M. M ; Taghavinia, N ; Kedia, M ; Saliba, M ; Sharif University of Technology
Royal Society of Chemistry
2021
Abstract
In the last decade, the power conversion efficiency (PCE) of solution-processed perovskite solar cells (PSCs) in the lab-scale has reached an incredible level of 25.5%. Generally, PSCs are composed of a stack consisting of a perovskite thin-film sandwiched between an electron transporting layer (ETL) and a hole transporting layer (HTL). Although the quality of the ETL and HTL interfaces with the perovskite thin-film is important, the quality of the perovskite thin-film is also critical to achieving high-performance PSCs. Low-temperature deposition of organic-inorganic perovskite thin-films by simple solution processes is one of the significant advantages of PSCs compared to other...
Optoelectronic properties of thermally coated tin selenide thin films for photovoltaics
, Article International Journal of Energy Research ; 2021 ; 0363907X (ISSN) ; Sharif, U ; Shahzad, N ; Kalam, A ; Al-Sehemi, A ; Alrobei, H ; Khesro, A ; Sharif University of Technology
John Wiley and Sons Ltd
2021
Abstract
In this study, 490 nm thin tin selenide thin films were deposited by facile co-evaporation techniques using Sn and Se sources on a clean glass substrate. The thin films were annealed at moderate annealing temperature followed by characterization and analysis. The thin annealed films possess polycrystalline nature and orthorhombic structure with an average grain size of 130 nm. The band gap assessed from absorption spectra for the highly annealed sample was 1.52 eV. The resistivity and sheet resistance were measured with four-probe techniques and the sheet resistance was =1.362 × 104 ohm for the highly annealed film. © 2021 John Wiley & Sons Ltd
Optoelectronic properties of thermally coated tin selenide thin films for photovoltaics
, Article International Journal of Energy Research ; 2021 ; 0363907X (ISSN) ; Sharif, U ; Shahzad, N ; Kalam, A ; Al-Sehemi, A ; Alrobei, H ; Khesro, A ; Sharif University of Technology
John Wiley and Sons Ltd
2021
Abstract
In this study, 490 nm thin tin selenide thin films were deposited by facile co-evaporation techniques using Sn and Se sources on a clean glass substrate. The thin films were annealed at moderate annealing temperature followed by characterization and analysis. The thin annealed films possess polycrystalline nature and orthorhombic structure with an average grain size of 130 nm. The band gap assessed from absorption spectra for the highly annealed sample was 1.52 eV. The resistivity and sheet resistance were measured with four-probe techniques and the sheet resistance was =1.362 × 104 ohm for the highly annealed film. © 2021 John Wiley & Sons Ltd
Circuit Model for Periodic Plasmonic Nanostructures Used as Light-rapping Back-structures in thin Film Solar Cells
, M.Sc. Thesis Sharif University of Technology ; Mehrany, Khashayar (Supervisor) ; Khavasi, Amin (Co-Advisor)
Abstract
In recent years, thin-film photovoltaic cells with thicknesses of less than 1-2 µm have been developed with potentially lower production costs. Due to the small thickness of the absorbing semiconductor in these cells, the absorption is inevitably low at energies close to the electronic band gap of the semiconductor. This is particularly a problem for thin-film devices. Recently، periodic metallic nanostructures supporting surface plasmons have been introduced as alternative solutions to achieve light trapping in thin-film solar cells.Full numerical methods are usually used for the analysis of these periodic structures. The main drawback of these methods is that they are time-consuming and...
Preparation of Suitable Membrane for NaOH Solution Enrichment
, M.Sc. Thesis Sharif University of Technology ; Musavi, Abbas (Supervisor) ; Bastani, Dariush (Supervisor)
Abstract
Sodium Hydroxide production industry is among the largest chemical industries that annually produces 66 million tons worldwide. NaOH which is produced through electrochemical cells needs to be further enriched. The use of membrane technology as a substitute for conventional processes has been a point of interest. Thin film composite membrane is among favorable membrane because of its ability to be customized layer by layer individually. In this thesis, for the purpose of making an optimized membrane for NaOH enrichment, we studied the preparation conditions and witnessed that by increasing MPD from 1.5 %wt. to 4.5%wt. The flux experiences a minimum at 3.5%wt, which is the maximum for...
Physical Investigation of Gasochromic Phenomena Mechanism in Tungsten Oxide Nanostructure
, Ph.D. Dissertation Sharif University of Technology ; Mahdavi, Mohammad (Supervisor) ; Iraji Zad, Azam (Supervisor)
Abstract
In the present thesis the fabrication of various tungsten oxide nanostructures (films and colloidal nanoparticles) with coverage of catalyst on their surfaces has been investigated which show gasochromic properties. Tungsten oxide films and nanoparticles were synthesized by pulsed laser abalation technique in vacuum and liquid environment, respectively. To activate the synthesized films and nanoparticles against hydrogen gas, the catalyst nanoparticles (Pd or Pt) were deposited onto their surface through hydrogen reduction of metal salt and electroless methods, respectively. The products were characterized by XPS, UV-Vis., AFM and DLS techniques. The prepared samples show significant color...
Numerical Investigation of Dewetting Over Topographicaly Srtuctured Substrate on Nanometric Scale
,
M.Sc. Thesis
Sharif University of Technology
;
Moosavi, Ali
(Supervisor)
Abstract
Thin liquid films on solid substrates are of considerable relevance in widespread of natural and technological fields. Examples are eye irrigation, biological cell interaction, tertiary oil recovery, coating, painting, lubrication, integrated circuits, micro- and nano-electronic devices, to name just a few. It is well known that liquid films are not always stable and there are verities of factors that may destabilize and expose the film to dynamical processes which leads to removal of the liquid from the substrate, the phenomenon so-called dewetting, either by nucleation or spinodal mechanisms. In many cases dewetting is destructive but there are several situation in which dewetting turns...
Synthesis and Coating of Gold Nanoparticles by Sol-Gel Method on the Glass Surface
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
In this project, the goal is to form gold nanoparticles on glass surface using Sol-Gel method, to create the appropriate physical and optical properties. To reach this purpose, the main point is to form the stable gel as a network of nanoparticles on glass surface. After coating, physical properties, surface properties and morphology were investigated. To investigate the absorption rate, the optical spectrum reflex had been appeared through 500-550 nm using UV-Visible test. Also, to observe morphology, particle size and distribution on the surface, the thin films have been tested via FESEM. Using a polymer template for gold nanoparticles, the structure of nanoparticles optimized...
The Effect of Porosity on Photocatalytic Properties of TiO2 Nanocoating Fabricated By Sol-Gel
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
This thesis is concerned with the synthesis and characterization of high porous Ti based on thin films and the effect of polymer agents on their photocatalytic properties. Ti films can demonstrate different properties like self -cleaning and treatment of broad range of aqueous pollutants when it is exposed to light of wavelength less than 400 nm. This is due to photocatalytic reaction occurring on film surface which results in film superhydrophilicity and the active oxygen species production. This active sites and radicals will cause oxidize organic pollutants and microbe adherent to the material surface.
In this study Ti thin films have been prepared by the sol-gel method from...
In this study Ti thin films have been prepared by the sol-gel method from...
Estimation of Material Properties and Residual Stress Induced in Metallic Thin Films Synthesized by Thermal Sintering
, M.Sc. Thesis Sharif University of Technology ; Akbari, Javad (Supervisor) ; Movahhedy, Mohammad Reza (Co-Advisor)
Abstract
Thin films of materials, in order to have magnificent structure and properties, can use in complicated technology such as; electronic, optic and magnetic systems. Printed interconnects can be made by the deposition of suspensions of metal nanoparticles (e.g., silver and gold) followed by thermal sintering. The nanoparticle sintering process involves atomic diffusion resulting in shrinkage. As a result, the interconnects are prone to residual stresses generated during the thermal sintering process. The residual stress can cause cracks and delamination in the thin films and can cause permanent geometrical changes in the underlying substrates which may affect the functionality of the...
Semiconductor TiO2-Al2O3 thin film gas sensors derived from aqueous particulate sol-gel process
, Article Materials Science in Semiconductor Processing ; Vol. 27, issue , 2014 , p. 711-718 ; Sharif University of Technology
Abstract
Nanostructured TiO2-Al2O3 films and powders were prepared by a straightforward aqueous particulate sol-gel route. Titanium (IV) isopropoxide and aluminum chloride were used as precursors, and hydroxypropyl cellulose was used as a polymeric fugitive agent in order to increase the porosity. The effect of Al:Ti molar ratio was studied on the crystallization behavior of the products. X-ray diffraction (XRD) revealed that the powders crystallized at 800°C, containing anatase-TiO2, rutile-TiO2 and cubic-Al2O3 phases. Furthermore, it was found that Al2O3 retarded the anatase to rutile transformation. Transmission electron microscope (TEM) image showed that one of the smallest crystallite sizes was...
Modeling the instability behavior of thin film devices: Fermi Level Pinning
, Article Superlattices and Microstructures ; Volume 117 , 2018 , Pages 399-405 ; 07496036 (ISSN) ; Ahmadpour, M ; Gorji, N. E ; Sharif University of Technology
Academic Press
2018
Abstract
We investigate the underlying physics of degradation/recovery of a metal/n-CdTe Schottcky junction under reverse or forward bias stressing conditions. We used Sah-Noyce-Shockley (SNS) theory to investigate if the swept of Fermi level pinning at different levels (under forward/reverse bias) is the origin of change in current-voltage characteristics of the device. This theory is based on Shockley-Read-Hall recombination within the depletion width and takes into account the interface defect levels. Fermi Level Pinning theory was primarily introduced by Ponpon and developed to thin film solar cells by Dharmadasa's group in Sheffield University-UK. The theory suggests that Fermi level pinning at...
Flux enhancement of thin-film composite membrane by graphene oxide incorporation
, Article Journal of Environmental Health Science and Engineering ; Volume 17, Issue 1 , 2019 , Pages 377-382 ; 2052336X (ISSN) ; Rashidi Mehrabadi, A ; Shayegan, J ; Mirabi, M ; Madaeni, S. S ; Sharif University of Technology
BioMed Central Ltd
2019
Abstract
Reverse Osmosis (RO) is a rapid-developing desalination technology; however, it suffers from inefficient energy consumption. To reduce energy consumption, in this study, reverse osmosis thin-film composite membrane (TFC) module was prepared and composed of m-phenylenediamine (MPD), graphene oxide, and 1,3,5-benzenetricarbonyl chloride (TMC) by interfacial polymerization on the surface of a polysulfone substrate. The graphene oxide was embedded in the mentioned thin-film composite by adding it to MPD aqueous solution to enhance permeation flux and, thus, reduce energy consumption. This study assessed the performance of the membrane using a lab-scale RO setup and evaluated permeability and...
Enhancing forward osmosis (FO) performance of polyethersulfone/polyamide (PES/PA) thin-film composite membrane via the incorporation of GQDs@UiO-66-NH2 particles
, Article Journal of Water Process Engineering ; Volume 33 , 2020 ; Bayrami, A ; Amini, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In this study, first, the UiO-66-NH2 metal-organic frameworks (MOFs) were modified with graphene quantum dots (GQDs) to facilitate the water attraction on MOF surface as well as improve their compatibility/affinity with the polyamide layer matrix of forward osmosis (FO) membranes. Next, to fabricate a new type of thin-film nanocomposite (TFN) membranes, the synthesized GQDs@UiO-66-NH2 composites are incorporated into the polyamide (PA) selective layer of FO membranes during the interfacial polymerization reaction of m-phenylenediamine (MPD) and trimesoyl chloride (TMC). The influence of the prepared fillers on the chemical structure, morphology, surface roughness and hydrophilicity of the PA...
Self-encapsulation of single-texture CoSi2 nanolayer by TaSi2
, Article Thin Solid Films ; Volume 516, Issue 18 , 31 July , 2008 , Pages 6008-6012 ; 00406090 (ISSN) ; Azimirad, R ; Moshfegh, A. Z ; Sharif University of Technology
2008
Abstract
In this work, we have studied single-texture formation of CoSi2 layer in heat-treated Co/Ta0.7W0.3/Si(100) structure. Moreover, self-encapsulation process of the CoSi2 layer and surface roughness of the encapsulated layer, as a contact layer, has been examined. A direct current magnetron co-sputtering technique was employed to deposit a 10 nm Ta0.7W0.3 alloy intermediate layer. After growth of the layer on the Si substrate, a 25 nm Co layer was deposited using thermal evaporation method. Post-annealing process of the films was treated in an N2(80%) + H2(20%) ambient in a temperature range from 400 to 1000 °C for 60 min. X-ray diffraction analysis showed that a single-texture CoSi2 layer with...
Applications of single-layered graphene sheets as mass sensors and atomistic dust detectors
, Article Solid State Communications ; Volume 145, Issue 4 , 2008 , Pages 168-172 ; 00381098 (ISSN) ; Ahmadian, M. T ; Vafai, A ; Sharif University of Technology
2008
Abstract
Molecular structural mechanics is implemented to model the vibrational behavior of defect-free single-layered graphene sheets (SLGSs) at constant temperature. To mimic these two-dimensional layers, zigzag and armchair models with cantilever and bridge boundary conditions are adopted. Fundamental frequencies of these nanostructures are calculated, and it is perceived that they are independent of the chirality and aspect ratio. The effects of point mass and atomistic dust on the fundamental frequencies are also considered in order to investigate the possibility of using SLGSs as sensors. The results show that the principal frequencies are highly sensitive to an added mass of the order of 1 0-...
The fractal study of Cu-Ni layer accumulation during electrodeposition under diffusion-controlled condition
, Article Materials Research Bulletin ; Volume 42, Issue 9 , 2007 , Pages 1769-1776 ; 00255408 (ISSN) ; Dolati, A ; Sharif University of Technology
2007
Abstract
The fractal study of thin layer films has been concerned by numerous studies, but it is a novel idea to use this method for interpretation of layer formation during electrocrystallization, simultaneously. In present study, Scharifker's equations were derived for instantaneous and progressive nucleation and 3D growth of hemispherical centers under diffusion-controlled condition to calculate in situ change of fractal dimension of surface. It was assumed that the layer could be formed completely when fractal dimension of surface inclined to 2. Moreover, the fractal analysis of AFM images has confirmed the presumed model. © 2006 Elsevier Ltd. All rights reserved
Elastic field of a nano disk shape defect in an fcc thin film
, Article 2007 2nd IEEE International Conference on Nano/Micro Engineered and Molecular Systems, IEEE NEMS 2007, Bangkok, 16 January 2007 through 19 January 2007 ; 2007 , Pages 142-146 ; 1424406102 (ISBN) ; 9781424406104 (ISBN) ; Pahlevani, L ; Hamed, E ; Sharif University of Technology
2007
Abstract
In this paper, we develop a theory to study the nano defects of various geometries within thin films. The considered thin films have face centered cubic (fee) structure. The eigenstrain method is combined with the long-range Sutton-Chen (SC) inter-atomic potential function which is appropriate for fee crystals. The disturbance caused by a defect in a thin film is determined from the equilibrium equation using the discrete Fourier transformation. The disturbed field is also determined using three dimensional (3D) Molecular Dynamics (MD) simulation in which the constant NVT ensemble is applied to the atomic system. For illustration, the problem of nano disk shape defect in thin film is studied...
Inclusion problems associated with thin fcc films: linkage between eigenstrain and inter-atomic potential
, Article Mechanics of Materials ; Volume 39, Issue 8 , 2007 , Pages 803-818 ; 01676636 (ISSN) ; Pahlevani, L ; Hamed, E ; Sharif University of Technology
2007
Abstract
Often, during fabrication of thin films on substrates, different types of defects may be introduced into the films. Recently, the determination of the elastic fields due to the self-assembly of quantum dots or strained islands in thin films has been of major concern. In the micromechanical studies, such strained islands are modeled by inclusions. This paper aims to develop a theory pertaining to the presence of nano-inclusions of various geometries within thin films having face centered cubic (fcc) structure. To this end, the notion of eigenstrain is combined with a many body inter-atomic potential suitable for fcc crystals. The interaction between atoms is modeled via Sutton-Chen (SC)...
Electrocatalytic oxidation of methanol on a nickel electrode modified by nickel dimethylglyoxime complex in alkaline medium
, Article Journal of Power Sources ; Volume 144, Issue 1 , 2005 , Pages 21-27 ; 03787753 (ISSN) ; Shahrokhian, S ; Asgari, M ; Ghannadi Maragheh, M ; Irannejad, L ; Khanchi, A ; Sharif University of Technology
2005
Abstract
Electrocatalytic oxidation of methanol on a nickel disc electrode coated with nickel dimethyglyoxime complex (NiDMG), conditioned by potential recycling in a potential range of 100-700 mV (versus SCE) is studied by cyclic voltammetry in alkaline medium (0.10 M NaOH). The results show that the NiODMG layer formed at the surface of electrode behaves as an efficient electrocatalyst for the oxidation of methanol in alkaline medium via Ni(III) species with the cross exchange reaction occurring through out the layer at a low concentration of methanol. A plausible mechanism was proposed for catalytic oxidation of methanol at this modified electrode. Moreover, the effects of various parameters such...