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Effect of TiO2 nanofiber density on organic-inorganic based hybrid solar cells
, Article International Journal of Engineering, Transactions A: Basics ; Vol. 27, issue. 7 , 2014 , p. 1133-1138 ; Kasaeian, A. B ; Nikfarjam, A. R ; Mohammadpour, R ; Sharif University of Technology
Abstract
In this work, a comparative study of hybrid solar cells based on P3HT and TiO2 nanofibers was accomplished. Electrospinning, a low cost production method for large area nanofibrous films, was employed to fabricate the organic-inorganic hybrid solar cells based on poly (3-hexylthiophene) and TiO2 nanofibers. The performance of the hybrid solar cells was analyzed for four density levels of TiO2 nanofibers which resulted in the average power conversion efficiency of about 0.0134% under AM 1.5 simulated illuminations (100 mWcm-2). It is found that the higher densities of TiO2 lead to more interface area and generating exciton, so the power conversion efficiency will be increased till the active...
Theoretical calculation of scattering efficiency of isotropic and anisotropic scattering particles employed in nanostructured solar cells
, Article Journal of Optics (United Kingdom) ; Vol. 16, issue. 5 , 2014 ; ISSN: 20408978 ; Mohammadpour, R ; Sharif University of Technology
Abstract
Light scattering design in dye and quantum dot sensitized solar cells is one of the main concerns in enhancing their light harvesting efficiency, and also in improving their power conversion efficiency. Herein, we present a theoretical analysis to calculate the dependence of the light scattering efficiency in dye solar cells that have employed scattering agents with various sizes and morphologies incorporated in nanostructured photoanodes with different designs. Various isotropic and anisotropic nanostructures, including filled and hollow spheres, spherical voids, nanowires and hollow fibres in a size range of 100 nm to 900 nm, have been considered as scattering centres. The scattering...
Development of an aqueous TiO2 paste in terms of morphological manipulation of nanostructured photoanode electrode of dye-sensitized solar cells
,
Article
Journal of Sol-Gel Science and Technology
;
Volume 75, Issue 2
,
August
,
2015
,
Pages 447-459
;
09280707 (ISSN)
; Mohammadi, M. R
;
Sharif University of Technology
Kluwer Academic Publishers
2015
Abstract
Abstract: A novel simple synthetic procedure for improving cell efficiency and reducing the production cost of TiO2 dye-sensitized solar cells (DSSCs) by modification and optimization of homemade formulated paste is reported. This is achieved in terms of morphological manipulation of deposited monolayer TiO2 films by controlling three processing parameters of paste formulation. These parameters are tailored to obtain a paste with proper viscosity suitable for spin-coating technique and to achieve uniform, homogeneous, and crack-free films with good connections between TiO2 grains and porous structure. Photovoltaic measurements show that TiO2 ...
Effect of crystallinity and morphology of TiO2 nano-structures on TiO2 :P3HT hybrid photovoltaic solar cells
,
Article
Applied Solar Energy (English translation of Geliotekhnika)
;
Volume 51, Issue 1
,
January
,
2015
,
Pages 34-40
;
0003701X (ISSN)
; Kasaeian, A. B
; Nikfarjam, A
; Akbarzadeh, A
; Mohammadpour, R
;
Sharif University of Technology
Allerton Press Incorporation
2015
Abstract
A comparative study has been made of hybrid solar cells based on poly(3-hexylthiophene) (P3HT) and different nano-structures of TiO2 . Electrospinning, which is a low cost production method for large area nanofibrous films, was employed to fabricate TiO2 nanofibers and spin coating method was employed to fabricate organic-inorganic hybrid solar cells based on P3HT and TiO2 nanostructures. The performance of the hybrid solar cells was analyzed for four density levels of the TiO2 nanostructure. It was found that higher densities of TiO2 leads to more interface area and generates excitons, so that the power conversion efficiency increases to...
One-pot synthesis of ZnO nanoparticles and submicron-aggregates for dye-sensitized solar cells
, Article Materials Letters ; Volume 139 , January , 2015 , Pages 433-436 ; 0167577X (ISSN) ; Nemati, A ; Malekshahi Byranvand, M ; Mohammadpour, R ; Faridi, H ; Sharif University of Technology
Elsevier
2015
Abstract
ZnO nanoparticles (NPs) and submicron aggregates (SMAs) were synthesized via a simple precipitation method by changing the amount of zinc acetate di-hydrate in absolute ethanol and synthesis time. Synthesized NPs and SMAs were characterized by FE-SEM, EDS, XRD, PL, and DRS and were used to fabricate dye-sensitized solar cells (DSSCs). The SMAs synthesized at moderate concentration (0.022 M) and with poly-dispersed distribution of the aggregates showed lower density of deep localized trap states as well as enhanced scattering features in comparison to NP-based electrode. As a result, power conversion efficiency (η) of about 2.56% with improved current density (Jsc) of 8.51 mA/cm2 were...
Micron-scale rod-like scattering particles for light trapping in nanostructured thin film solar cells
, Article RSC Advances ; Volume 5, Issue 105 , 2015 , Pages 86050-86055 ; 20462069 (ISSN) ; Taghavinia, N ; Nemati Kharat, A ; Dabirian, A ; Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
Spherical dielectric particles, nanofibers, and nanorods have been widely used as embedded scattering objects in nanostructured thin film solar cells. Here we propose micron-scale rod-like dielectric particles as a more effective alternative to the spherical ones for light trapping in thin film solar cells. The superior performance of these micro-rods is attributed to their larger scattering efficiency relative to the spherical particles as evidenced by full-wave optical calculations. Using a one-pot process, 1.7 μm-long bullet-shaped silica rods with 330 nm diameter are synthesized and their concentration in a N719-sensitized solar cell is optimized. A solar cell with an optimal...
Photonic design of embedded dielectric scatterers for dye sensitized solar cells
, Article RSC Advances ; Volume 5, Issue 42 , Mar , 2015 , Pages 33098-33104 ; 20462069 (ISSN) ; Dabirian, A ; Nemati Kharat, A ; Taghavinia, N ; Sharif University of Technology
Abstract
Embedded dielectric scatterers comprise an important approach for light trapping in dye-sensitized solar cells (DSCs) due to their simple fabrication process. The challenge in applying these scatterers lies in finding the optimal dimensions and concentration of the scatterers. This requires many experiments and it is often quite difficult to have a starting point for optimizing the concentration. Based on theories of light propagation in random media, we propose a simple model for DSCs with embedded silica spherical particles. Then, by full-wave optical calculations, we determine a narrow range for the concentration of silica particles that leads to the largest optical absorption in the...
Three-dimensional Graphene Electrode for Depleted-hetreojunction Quantum Dot Solar Cells
, Article Procedia Engineering, 28 June 2015 through 3 July 2015 ; Volume 141 , 2016 , Pages 38-46 ; 18777058 (ISSN) ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
Herein, a simple and novel method was used to synthesize a new structure of graphene which can be called hollow graphene. First, the ZnO-Graphene QDs synthesized by solution method and then ZnO QDs were dissolved from this structure using an acidic solution to obtain hollow structure of graphene. Afterward, this structure was used in PbS QDs solar cell in order to improve the transport of electron and decrease the recombination of the carriers. A power conversion efficiency of 5.3% was obtained using hollow graphene as a fast electron extraction layer due to the enhancement of EQE and current density. The improvement of PCE in this device was corresponded to efficient photosensitized...
Interface engineering of perovskite solar cell using a reduced-graphene scaffold
, Article Journal of Physical Chemistry C ; Volume 120, Issue 35 , Volume 120, Issue 35 , 2016 , Pages 19531-19536 ; 19327447 (ISSN) ; Tavakoli, R ; Hasanzadeh, S ; Mirfasih, M. H ; Sharif University of Technology
American Chemical Society
Abstract
Interface engineering of solar cell device is a prominent strategy to improve the device performance. Herein, we synthesize reduced-graphene scaffold (rGS) by using a new and simple chemical approach. In this regard, we synthesize a hollow structure of graphene and then fabricate a three-dimensional scaffold of graphene with a superior surface area using electrophoretic process. We employ this scaffold as an interface layer between the electron transfer and absorber layers in perovskite solar cell. The characterization tests and photovoltaic results show that rGS improves the carrier transportation, yielding a 27% improvement in device performance as compared to conventional device. Finally,...
A novel organic–inorganic hybrid tandem solar cell with inverted structure
, Article Applied Physics A: Materials Science and Processing ; Volume 123, Issue 4 , 2017 ; 09478396 (ISSN) ; Faez, R ; Sharif University of Technology
Springer Verlag
2017
Abstract
A novel organic–inorganic hybrid tandem solar cell with inverted structure is proposed. This efficient double-junction hybrid tandem solar cell consists of a single-junction hydrogenated amorphous silicon (a-Si:H) subcell with n-i-p structure as front cell and a P3HT:PCBM organic subcell with inverted structure as back cell. In order to optimize the hybrid tandem cell, we have performed a simulation based on transfer matrix method. We have compared the characteristics of this novel structure with a conventional structure. As a result, a power conversion efficiency (PCE) of 6.1 and 24% improvement compared to the conventional hybrid tandem cell was achieved. We also discuss the high potential...
Synthesis and characterization of new triphenylamine-based dyes with novel anchoring groups for dye-sensitized solar cell applications
, Article Journal of Materials Science: Materials in Electronics ; Volume 28, Issue 2 , 2017 , Pages 1859-1868 ; 09574522 (ISSN) ; Hosseinzadeh, B ; Azari, M ; Ghahary, R ; Sharif University of Technology
Springer New York LLC
2017
Abstract
Three new chromophores based on the triphenylamine (MM, DM, DN) with various novel electron withdrawing anchoring groups have been synthesized for use in dye-sensitized solar cells (DSSCs). The sensitizers were characterized by 1H and 13C NMR, Mass, UV–Vis, and electrochemical analysis. The HOMO and LUMO electron distributions of the sensitizers were calculated using density functional theory on a B3LYP level for geometry optimization. The DSSC device based on DM dye showed the best photovoltaic performance among MM and DN dyes: maximum monochromatic incident photon-to-current conversion efficiency (IPCE) of 98 %, short circuit current (JSC) of 4.58 mA/cm2, open circuit voltage (VOC) of...
Simulation analysis of inverted organic solar cells with grating structure: undesirable effects of high absorption near grating anode
, Article Optik ; Volume 154 , February , 2018 , Pages 453-458 ; 00304026 (ISSN) ; Faez, R ; Sharif University of Technology
Elsevier GmbH
2018
Abstract
An inverted organic solar cell (IOSC) with nanograting array as anode of the cell has been simulated and analyzed using a combined electrical and optical approach. We have used finite difference time domain (FDTD) method for optimizing device structure. We have compared the characteristics of the IOSC with grating structure with a reference IOSC without grating structure. As a result, an improvement of 11% and 26% in power conversion efficiency (PCE) and short circuit current (JSC) compared to the reference structure was achieved. An analysis is provided on the origin of reduced fill factor (FF) in the IOSC with grating structure. We also have discussed about disadvantage of using optical...
Photovoltaic performance improvement in vacuum-assisted meniscus printed triple-cation mixed-halide perovskite films by surfactant engineering
, Article ACS Applied Energy Materials ; Volume 2, Issue 9 , 2019 , Pages 6209-6217 ; 25740962 (ISSN) ; Abdollah Zadeh, A ; Dehghani, M ; Taghavinia, N ; Sharif University of Technology
American Chemical Society
2019
Abstract
Scalable coating methods have recently emerged as practical alternative deposition techniques to the conventional spin-coating despite their lower yielding power conversion efficiencies (PCEs). The most important barrier acting against the use of scalable deposition methods to get a highly absorbing (>95%) film with controlled morphology in the high crystallinity of perovskite particles is the impossibility of antisolvent dripping during the deposition. Here, we demonstrate the positive role of both the surfactant-engineering and the vacuum-annealing (<100 Pa) process in improving the device performance to overcome this limit. A detailed optimization of the vacuum-assisted meniscus printing...
A new co-solvent assisted CuSCN deposition approach for better coverage and improvement of the energy conversion efficiency of corresponding mixed halides perovskite solar cells
, Article Journal of Materials Science: Materials in Electronics ; Volume 30, Issue 12 , 2019 , Pages 11576-11587 ; 09574522 (ISSN) ; Marandi, M ; Iraji zad, A ; Taghavinia, N ; Sharif University of Technology
Springer New York LLC
2019
Abstract
In this research, inorganic copper thiocyanate (CuSCN) hole transport layer (HTL) was applied in conventional structure of perovskite solar cells (PSCs). Besides, mixed halides perovskite (Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3) was utilized as the light absorbing layer and deposited on FTO/compact TiO2 substrates through a one-step coating method in ambient condition. The mentioned perovskite is more stable against high temperature, high irradiation and humidity compared to commonly applied MAPbI3 perovskite. Nevertheless, the CuSCN could not be well dissolved in usual dipropyl sulfide solution and should be deposited for several times to achieve suitable thickness, this could reduce the...
Surface treatment of perovskite layer with guanidinium iodide leads to enhanced moisture stability and improved efficiency of perovskite solar cells
, Article Advanced Materials Interfaces ; Volume 7, Issue 14 , 2020 ; Prochowicz, D ; Tavakoli, M. M ; Yadav, P ; Hong, C. K ; Sharif University of Technology
Wiley-VCH Verlag
2020
Abstract
Interfacial engineering between the perovskite and hole transport layers has emerged as an effective way to improve perovskite solar cell (PSC) performance. A variety of organic halide salts are developed to passivate the traps and enhance the charge carrier transport. Here, the use of guanidinium iodide (GuaI) for interfacial modification of mixed-cation (Cs)x(FA)1−xPbI3 perovskite films, which results in the formation of a low-dimensional δ-FAPbI3-like phase on the 3D perovskite surface, is reported. The presence of this thin layer facilitates charge transfer at interfaces and reduces charge carrier recombination pathways as evidenced by enhanced carrier lifetimes and favorable interfacial...
A Dopant-free hole transporting layer for efficient and stable planar perovskite solar cells
, Article Physica Status Solidi - Rapid Research Letters ; Volume 14, Issue 7 , 2020 ; Si, H ; Yadav, P ; Prochowicz, D ; Tavakoli, R ; Sharif University of Technology
Wiley-VCH Verlag
2020
Abstract
Herein, a new dopant-free organic material, PV2000, as a stable hole transporting layer (HTL) for the fabrication of stable and efficient perovskite solar cells (PSCs) is introduced. For this purpose, planar PSCs using a triple-A cation perovskite composition are fabricated and the commonly used 2,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (spiro-OMeTAD) HTL is replaced by dopant-free PV2000 polymer. The characterization results disclose that the PV2000 has a great thermal stability, good hole mobility, and suitable band alignment that matches well with the valence band of triple-A cation perovskite. After proper optimization of PV2000 film thickness, a planar PSC...
Mesoporous TiO2 microbead electrodes for cobalt-mediator-based dye-sensitized solar cells
, Article Journal of Physical Chemistry C ; Vol. 118, issue. 30 , July , 2014 , p. 16472-16478 ; ISSN: 19327447 ; Taghavinia, N ; Hagfeldt, A ; Boschloo, G ; Sharif University of Technology
Abstract
Light scattering, porosity, surface area, and morphology of TiO2 working electrode can affect the power conversion efficiency of dye -sensitized solar cells dramatically. Here mesoporous TiO2 microbeads were tested as working electrode in dye-sensitized solar cells based on cobalt tris-bipyridine electrolyte. Power conversion efficiencies up to 6.4% were obtained with D35 dye adsorbed onto the light-scattering microbeads. Electron transport, studied using small light perturbation methods, was found to be significantly faster in the microbead films than in standard mesoporous TiO 2 films. This was attributed to the favorable assembly of nanocrystals in the microbeads, which can increase the...
Controlling electron injection and electron transport of dye-sensitized solar cells aided by incorporating CNTs into a Cr-doped TiO2 photoanode
, Article Electrochimica Acta ; Volume 111 , 2013 , Pages 921-929 ; 00134686 (ISSN) ; Mohammadi, M. R ; Bakhshayesh, A. M ; Abdi Jalebi, M ; Sharif University of Technology
2013
Abstract
In the present work, we focused on simultaneously control electron injection and electron transport, in dye-sensitized solar cells (DSSCs), aided by introducing Cr3+ and CNTs into a TiO2 photoanode, respectively. X-ray photoelectron spectroscopy (XPS) revealed that, Cr 3+ and CNTs were successfully incorporated into the TiO2 lattice without forming secondary phases. X-ray diffraction (XRD) analysis showed that Cr introduction has perfectly balanced the amount of anatase and rutile phases in order to accomplish a more efficient cell. Field emission scanning electron microscope (FE-SEM) images showed deposited films to have a porous morphology composed of nanoparticles and TiO2 nanoparticles...
Dependence of photovoltaic performance of solvothermally prepared CdS/CdTe solar cells on morphology and thickness of window and absorber layers
, Article Journal of Materials Science: Materials in Electronics ; Volume 24, Issue 9 , 2013 , Pages 3564-3574 ; 09574522 (ISSN) ; Mohammadi, M. R ; Sharif University of Technology
2013
Abstract
In the present work a new strategy for straightforward fabrication of CdS/CdTe solar cells, containing CdS nanowires and nanoparticles as a window layer and CdTe nanoparticles and microparticles as an absorber layer, are reported. CdS and CdTe nanostructures were synthesized by solvothermal method. X-ray diffraction analysis revealed that highly pure and crystallized CdS nanowires and nanoparticles with hexagonal structure and CdTe nanoparticles with cubic structure were obtained. Atomic force microscope and field emission scanning electron microscope images showed that CdS nanowires with length of several μm and average diameter of 35 nm, CdS nanoparticles with average particle size of 32...
The improvement of electron transport rate of TiO2 dye-sensitized solar cells using mixed nanostructures with different phase compositions
, Article Ceramics International ; Volume 39, Issue 7 , 2013 , Pages 7343-7353 ; 02728842 (ISSN) ; Mohammadi, M. R ; Sharif University of Technology
2013
Abstract
Dye-sensitized solar cells (DSCCs) in the form of mixed nanostructures containing TiO2 nanoparticles and nanowires with different weight ratios and phase compositions are reported. X-ray diffraction and field emission scanning electron microscopy analyses revealed that the synthesized TiO 2 nanoparticles had average crystallite size in the range 21-39 nm, whereas TiO2 nanowires showed diameter in the range 20-50 nm. The indirect optical band gap energy of TiO2 nanowires, anatase- and rutile-TiO2 nanoparticles was calculated to be 3.35, 3.28 and 3.17 eV, respectively. The power conversion efficiency of the solar cells changed with nanowire to nanoparticle weight ratio, reaching a maximum at a...