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    Monolithic quantum dot sensitized solar cells

    , Article Journal of Physics D: Applied Physics ; Volume 46, Issue 48 , December , 2013 ; 00223727 (ISSN) Samadpour, M ; Ghane, Z ; Ghazyani, N ; Tajabadi, F ; Taghavinia, N ; Sharif University of Technology
    We report a new design of solar cells based on semiconductor quantum dots (QDs), monolithic quantum dot sensitized solar cells (MQDSCs). MQDSCs offer the prospect of having lower cost and a simpler manufacturing process in comparison to conventional double substrate QDSCs. Our proposed monolithic QDSCs have a triple-layer structure, composed of a CdS sensitized mesoporous TiO2 photoanode, a scattering layer made by a core-shell structure of TiO 2/SiO2, and a carbon active/graphite counter electrode layer, which are all deposited on a single fluorine doped tin oxide (FTO) glass substrate. Mesoporous TiO2 was sensitized with CdS QDs by successive ionic layer adsorption and reaction. Here,... 

    Supercritical synthesis and characterization of graphene-pbs quantum dots composite with enhanced photovoltaic properties

    , Article Industrial and Engineering Chemistry Research ; Volume 54, Issue 30 , 2015 , Pages 7382-7392 ; 08885885 (ISSN) Tayyebi, A ; Tavakoli, M. M ; Outokesh, M ; Shafiekhani, A ; Simchi, A ; Sharif University of Technology
    American Chemical Society  2015
    Lead sulfide quantum dots (PbS QDs) were decorated onto a graphene surface in a semi-core-shell structure using supercritical ethanol. The temperature of ethanol played significant role in controlling size and agglomeration of QDs as well as the extent of reduction of graphene. Average size of the QDs was estimated by transmission electron microscopy to be around 3.96 nm and by quantum models to be about 4.34 nm. PbS QDs prepared at 330 °C were of high purity, and the yield was 99%. Instrumental and chemical analyses demonstrated formation of a strong bond between PbS QDs and graphene, through a Pb-O-C bridge. UV and photoluminescence measurements along with theoretical considerations... 

    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) Yadav, P ; 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
    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... 

    New organic dyes with diphenylamine core for dye-sensitized solar cells

    , Article Journal of Materials Science: Materials in Electronics ; Volume 29, Issue 8 , April , 2018 , Pages 6323-6336 ; 09574522 (ISSN) Salimi Beni, A. R ; Karami, M ; Hosseinzadeh, B ; Ghahary, R ; Sharif University of Technology
    Springer New York LLC  2018
    In the current investigation, four novel donoracceptor type organic dyes including (DPA-Ba, DPA-Hy, DPA-Rh, DPA-Cy), are proposed and their photophysical and electrochemical properties as well as dye-sensitized solar cell performance are systematically investigated. Among these dyes diphenylamine is utilized as an-electron donor while barbituric acid, hydantoin, rhodanine-n-acetic acid and cyano acetic acid, are proposed as anchoring groups as dye-sensitized solar cells (DSSCs). The synthesized dyes are characterized using FT-IR, NMR, mass spectrometry, absorbance and electrochemical measurements. The photophysical, electrochemical and photovoltaic properties of the solar cells based on... 

    Graphene/PbS as a novel counter electrode for quantum dot sensitized solar cells

    , Article ACS Photonics ; Vol. 1, issue. 4 , March , 2014 , pp. 323-330 ; ISSN: 23304022 Parand, P ; Samadpour, M ; Esfandiar, A ; Iraji Zad, A ; Sharif University of Technology
    PbS nanoparticles were in situ deposited on graphene sheets by a successive ionic liquid adsorption and reaction method to prepare a graphene/PbS composite counter electrode for CdS/CdSe quantum dot sensitized solar cells (QDSCs). Under 1 sun illumination, the cells with graphene/PbS counter electrodes (CEs) show a maximum energy conversion efficiency of 2.63%, which is remarkably higher than that of those employing PbS (1.28%) or graphene (0.23%) CEs. Electrochemical impedance spectroscopy analysis shows that graphene/PbS composite counter electrodes have lower charge-transfer resistance at the interface of the CE and the polysulfide redox electrolyte, compared to those cells with PbS and... 

    Nitrogen-doped submicron-size TiO2 particles as bifunctional light scatterers in dye-sensitized solar cells

    , Article Applied Physics A: Materials Science and Processing ; Volume 119, Issue 4 , 2015 , Pages 1283-1290 ; 09478396 (ISSN) Shogh, S ; Mohammadpour, R ; Iraji zad, A ; Taghavinia, N ; Sharif University of Technology
    Springer Verlag  2015
    The structural, electrical, optical, and photovoltaic properties of aggregated submicron nitrogen-doped TiO2 particles (NTiO2) and the influence of utilizing them, in comparison with undoped ones, as the light-scattering layer of dye-sensitized solar cells were investigated. Field emission scanning electron microscope, X-ray diffraction, and diffuse reflectance spectra showed that both type samples have similar morphology, crystal phase, and scattering feature. Moreover, photoluminescence, Mott–Schottkey, and photovoltaic characteristics such as IMPS/IMVS and charge extraction analysis indicated that the NTiO2 layer is an efficient scatterer in two aspects: enhancement of light-harvesting... 

    Effect of ZnO nanoparticles coating layers on top of ZnO nanowires for morphological, optical, and photovoltaic properties of dye-sensitized solar cells

    , Article Micromachines ; Volume 10, Issue 12 , 2019 ; 2072666X (ISSN) Saleem, M ; Farooq, W. A ; Iftikhar Khan, M ; Niaz Akhtar, M ; Rehman, S. U ; Ahmad, N ; Khalid, M ; Atif, M ; AlMutairi, M. A ; Irfan, M ; Sharif University of Technology
    MDPI AG  2019
    This paper reports on the synthesis of ZnO nanowires (NWs), as well asthe compound nanostructures of nanoparticles (NPs) and nanowires (NWs+NPs) with different coating layers of NPs on the top of NWs and their integration in dye-sensitized solar cells (DSSCs). In compound nanostructures, NWs offer direct electrical pathways for fast electron transfer, and the NPs of ZnOdispread and fill the interstices between the NWs of ZnO, offering a huge surface area for enough dye anchoring and promoting light harvesting. A significant photocurrent density of 2.64mA/cm2 and energy conversion efficiency of 1.43% was obtained with NWs-based DSSCs. The total solar-to-electric energy conversion efficiency... 

    Effect of indium ratio in CuInxGa1-xS2/carbon hole collecting electrode for perovskite solar cells

    , Article Journal of Power Sources ; Volume 475 , 2020 Forouzandeh, M ; Behrouznejad, F ; Ghavaminia, E ; Khosroshahi, R ; Li, X ; Zhan, Y ; Liao, Y ; Ning, Z ; Taghavinia, N ; Sharif University of Technology
    Elsevier B.V  2020
    Perovskite solar cells (PSCs) have excellent photovoltaic properties. There are, however, challenges of materials cost and device stability to be solved before commercializing them. Utilizing low-cost inorganic hole transport materials (HTM) as a replacement for spiro-OMeTAD, and replacing the Au electrode with printable carbon could be important steps in this regard. For this purpose, CuInxGa1-xS2 (x = 1, 0.75, 0.5, 0.25, 0) nanoparticle layers are deposited as inorganic HTMs with carbon composite electrode as the back electrode. Photovoltaic properties of PSCs with CuInxGa1-xS2/Carbon hole collecting electrodes are studied by changing the In ratio in the HTM layer. Results from impedance...