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mott-schottky
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Reproducible electrochemical analysis of nanostructured Cu2O using a non-aqueous 3-methoxypropionitrile-based electrolyte
, Article Electrochemistry Communications ; Volume 86 , 2018 , Pages 1-5 ; 13882481 (ISSN) ; Iraji zad, A ; Mohammadpour, R ; Sharif University of Technology
Elsevier Inc
2018
Abstract
Cu2O is an attractive material in terms of semiconducting properties and is considered a leading candidate in all-oxide photovoltaics. Electrochemical analysis of Cu2O, including Mott-Schottky (MS) and impedance spectroscopy (IS), provides a wealth of data on charge carriers, Fermi level and interface properties. MS and IS are usually measured in aqueous solutions. However, Cu2O is easily reduced or oxidized to Cu or CuO in aqueous solutions, the layer peels off after the analysis and there is a small voltage window for the tests. In some cases, an anti-corrosive n-type barrier layer is employed on top of the bare Cu2O electrode to make the measurement possible, which could result in...
Electrochemical determination of CdS band edges and semiconducting parameters
, Article Bulletin of the Chemical Society of Japan ; Volume 88, Issue 6 , February , 2015 , Pages 814-820 ; 00092673 (ISSN) ; Jafarian, M ; Mahjani, M. G ; Gobal, F ; Heidaripour, A ; Sharif University of Technology
Chemical Society of Japan
2015
Abstract
Cadmium sulfide (CdS) thin film was electrodeposited on indium tin oxide (ITO) by chronoamperometry. The SEM images showed that hexagonal sheets of CdS deposited on the ITO surface. The X-ray diffraction (XRD) analysis confirmed this structure for CdS crystals and the average of crystalline size and the lattice constant parameters are approximately 39.54 and a = 0.4136, c = 0.6696 nm respectively. Photo-electrochemical investigations were performed by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) techniques. CdS band edges and density of states (DOS) were determined by CV technique. The band gap energy (Ebg ) was measured...
Elucidation of charge recombination and accumulation mechanism in mixed perovskite solar cells
, Article Journal of Physical Chemistry C ; Volume 122, Issue 27 , 2018 , Pages 15149-15154 ; 19327447 (ISSN) ; Turren Cruz, S. H ; Prochowicz, D ; Tavakoli, M. M ; Pandey, K ; Zakeeruddin, S. M ; Gratzel, M ; Hagfeldt, A ; Saliba, M ; Sharif University of Technology
American Chemical Society
2018
Abstract
Organic-inorganic perovskite solar cells (PSCs) have gained considerable attention owing to their impressive photovoltaic properties and simple device manufacturing. In general, PSC employs a perovskite absorber material sandwiched between an electron and hole selective transport layer optimized with respect to optimal band alignment, efficient charge collection, and low interfacial recombination. The interfaces between the perovskite absorber and respective selective contacts play a crucial role in determining photovoltaic performance and stability of PSCs. However, a fundamental understanding is lacking, and there is poor understanding in controlling the physical processes at the...
AC impedance and cyclic voltammetry studies on PbS semiconducting film prepared by electrodeposition
, Article Journal of Electroanalytical Chemistry ; Volume 661, Issue 1 , 2011 , Pages 265-269 ; 15726657 (ISSN) ; Jafarian, M ; Danaee, I ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
Abstract
Semiconducting lead sulfide film was deposited on Stainless Steel (SS) electrode by cyclic voltammetry (CV) at room temperature. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry were used to investigate the electrochemical properties of PbS film in Na2SO4 solution. The voltammetric results showed that oxidative dissolution of PbS film occurred at about 0.21 V vs. Ag/AgCl and total film detachment from the surface occurs with increasing potential. It is concluded that the electrode surface was not passivated by sulfur produced from oxidative dissolution of PbS film. Also, cathodic reduction of the film continued to beyond the hydrogen evolution at -1.35 V vs. Ag/AgCl....
Fabrication of Nanostructure Cuprous Oxide Films for Photovoltaic Systems
, Ph.D. Dissertation Sharif University of Technology ; Iraji Zad, Azam (Supervisor) ; Mohammadpour, Raheleh (Supervisor)
Abstract
Metal oxide semiconductors are promising materials for photovoltaic systems, because they are chemically stable, almost non-toxic and abundant. These materials are cheap and have low cost fabrication process. Cu2O is the most popular metal oxide semiconductor to absorb light in Photovoltaic (PV) applications, and photocathode in the photoelectrochemical systems.In this project, thermal oxide and electrodeposition methods, both interesting and cheap, were applied for preparing Cu2O films. As inexpensive materials results in low-minority carrier diffusion length, we report on surface engineering of bulk Cu2O photocathode thorough employing nanorods of copper oxide with the average lengths of...
The effect of lithium doping in solution-processed nickel oxide films for perovskite solar cells
, Article ChemPhysChem ; Volume 20, Issue 24 , 2019 , Pages 3322-3327 ; 14394235 (ISSN) ; Sveinbjornsson, K ; Boschloo, G ; Taghavinia, N ; Sharif University of Technology
Wiley-VCH Verlag
2019
Abstract
The effect of substitutional Li doping into NiOx hole transporting layer (HTL) for use in inverted perovskite solar cells was systematically studied. Li doped NiOx thin films with preferential crystal growth along the (111) plane were deposited using a simple solution-based process. Mott-Schottky analysis showed that hole carrier concentration (NA) is doubled by Li doping. Utilizing 4 % Li in NiOx improved the power conversion efficiency (PCE) of solar devices from 9.0 % to 12.6 %. Photoluminescence quenching investigations demonstrate better hole capturing properties of Li:NiOx compared to that of NiOx, leading to higher current densities by Li doping. The electrical conductivity of NiOx is...
Improvement of planar perovskite solar cells by using solution processed SnO2/CdS as electron transport layer
, Article Solar Energy ; Volume 191 , 2019 , Pages 647-653 ; 0038092X (ISSN) ; Javadpour, S ; Taghavinia, N ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
The efficiency of planar perovskite solar cells (PSCs) with SnO2 as electron transport layer is already more than 19% achieved under controlled atmosphere. PSCs with solution processed SnO2 show high hysteresis and low fill factor. One way to improve the planar PSCs is using buffer layer between electron transport layer and perovskite to enhance the photo-electron extraction process. In this study, SnO2 and SnO2/CdS layers were fabricated by solution process using a suspension including CdS nanoparticles synthesized via a simple solution route. Then planar PSCs with the structure of Glass/FTO/ETL/Perovskite/Sprio-OMeTAD/Au were fabricated in ambient air condition using SnO2 and SnO2/CdS as...
Study on spray-pyrolyzed In2S3 thin films, targeted as electron transport layer in solar energy
, Article Journal of Photonics for Energy ; Volume 10, Issue 2 , 2020 ; Heidariramsheh, M ; Ghorashi, S. M. B ; Taghavinia, N ; Mahdavi, S. M ; Sharif University of Technology
SPIE
2020
Abstract
Efficient electron transport layers (ETLs) play a pivotal role in the performance of solar cells. In recent years, Indium sulfide (In2S3) has been studied as a promising ETL in CuInGaS(e)2, Cu2ZnSnS(e)4, and perovskite solar cells. Despite several studies on spray-deposited In2S3, there is no complete experimental investigation on In2S3 thin films. The effect of the molar ratio of S/In and the type of indium precursor on the structural, morphological, optical, and electrical properties of sprayed-In2S3 layers has been studied. Films were characterized using x-ray diffraction, scanning electron microscopy (SEM), optical transmission (UV-Vis), Mott-Schottky analysis, four-point probe, and...
Enhanced performance of planar perovskite solar cells using TiO2/SnO2 and TiO2/WO3 bilayer structures: Roles of the interfacial layers
, Article Solar Energy ; Volume 208 , 2020 , Pages 697-707 ; Ranjbar, M ; Kermanpur, A ; Taghavinia, N ; Minbashi, M ; Forouzandeh, M ; Ebadi, F ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In planar perovskite solar cells (PSCs), engineering the extraction and recombination of electron–hole pairs by modification of the electron transport layer (ETL)/perovskite interface is very vital for obtaining high performance. The main idea here is to improve properties of the TiO2/perovskite interface by inserting an ultra-thin layer (UTL) of WO3 or SnO2 with the thickness of less than 10 nm by RF magnetron sputtering method. The structural and electrical characteristics of the samples were tested by XRD, AFM, FE-SEM, Mott-Schottky analysis, UV–Vis spectroscopy, J-V characterization and electrochemical impedance spectroscopy (EIS). It was found that the bilayer structured ETLs exhibit...
Robust water splitting on staggered gap heterojunctions based on WO3∖WS2–MoS2 nanostructures
, Article Renewable Energy ; Volume 162 , December , 2020 , Pages 504-512 ; Simchi, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
The high charge carrier recombination rate and weak oxygen evolution kinetics have impeded the efficiency of WO3 photoelectrodes for water splitting. We present a novel type II heterojunction semiconductor based on mixed WS2 and MoS2 nanosheets on WO3 nanoflakes hydrothermally grown on highly porous W skeletons. The chemically exfoliated transition metal dichalcogenide (TMD) sheets with submicrometric lateral sizes were deposited on the surface of WO3 nanoflakes by the electrophoretic technique to fabricate a staggered gap heterojunction. The photoanode exhibited an impressive current density of 14.9 mA cm−2 at 1.23 VRHE which comprised ∼1.7 mA cm−2 photocurrent under 100 mW cm−2 simulated...
Aqueous spray pyrolysis of CuInSe2 thin films: Study of different indium salts in precursor solution on physical and electrical properties of sprayed thin films
, Article Materials Science in Semiconductor Processing ; Volume 126 , 2021 ; 13698001 (ISSN) ; Bagher Ghorashi, S. M ; Tajabadi, F ; Taghavinia, N ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Herein, we deposited CuInSe2(CISe) thin films by using aqueous spray deposition method and post selenization process. The effect of different indium precursor salts including indium chloride, indium nitrate and indium acetate on the structural, morphological, optical and electrical properties of sprayed CISe layers has been studied by using x-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM-EDS), optical transmission (UV–Vis), Mott-Schottky analysis, I–V dark measurements. Although all the deposited thin films show a chalcopyrite tetragonal ordering structure of CISe, the crystallinity, morphology, and electrical characteristics are strongly influenced by the type of...
Electrical and optical characterization of sprayed In2S3 thin films as an electron transporting layer in high efficient perovskite solar cells
, Article Solar Energy ; Volume 215 , 2021 , Pages 356-366 ; 0038092X (ISSN) ; Minbashi, M ; Ghorashi, S. M. B ; Ghobadi, A ; Ehsani, M. H ; Heidariramsheh, M ; Hajjiah, A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
This study represents the investigation of In2S3 thin films, which have been deposited with different Indium salts (Chloride, Acetate, and Nitrate) using the Chemical Spray Pyrolysis (CSP) method. The Mott-Schottky analysis has been used in case of studying the electrical properties of films such as conduction and valence band, carrier densities, Fermi level (Efn), flat band potential, and semiconductor type. In the next step, the Rb1MAFA perovskite solar cell has been simulated, and the results have been validated by the experimental data (with the least parameters for fitting). Finally, In2S3 layers have been inserted on the SnO2 layer to decrease the recombination rate and enhance the...
Plastic injection molding dies using hybrid additively manufactured 420/CX stainless steels: electrochemical considerations
, Article npj Materials Degradation ; Volume 6, Issue 1 , 2022 ; 23972106 (ISSN) ; Samei, J ; Sanjari, M ; Jahanbakht, M ; Amirkhiz, B. S ; Mohammadi, M ; Sharif University of Technology
Nature Publishing Group
2022
Abstract
This research focused on the corrosion resistance and microstructure of hybrid additively manufactured (HAM) samples of AISI 420/CX (420/CX SS) stainless steels. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and Mott–Schottky analyses as well as the electrochemical noise (EN) technique were used to evaluate the electrochemical behavior of the as-built and heat-treated HAM parts in NaCl solution. The results showed a more protective passive layer formed on the CX SS side. The distribution of Cr-rich M23C6 carbides in matrix of 420 SS side resulted in a lower corrosion resistance compared to the CX SS side. The noise data analysis confirmed an increase in the...
Surface modification of carbon steel by ZnO-graphene nano-hybrid thin film
, Article Surface and Coatings Technology ; Volume 363 , 2019 , Pages 1-11 ; 02578972 (ISSN) ; Ghorbani, M ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Application of corrosion resistant coatings is one of the most widely used means of protecting steel. Zinc coated (galvanize) steel, is well known for galvanic protection of steel substrates and nowadays, particular attention has been paid to the coupling of graphene oxide (GO) with metallic materials, in order to lessen corrosion rate. In this research, an isopropanol supercritical reducing environment prepared to make zinc ions bond directly with graphene oxides, to form a button shape hybrids of ZnO-Graphene (ZnOG). The hybridized bonding between zinc and graphene oxide is confirmed by Fourier Transform Infra-Red analysis. And the morphology revealed, using a Field Emission Scanning...