Search for: device-stability
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    Highly efficient and stable perovskite solar cells based on a low-cost carbon cloth

    , Article Advanced Energy Materials ; Volume 6, Issue 20 , 2016 ; 16146832 (ISSN) Gholipour, S ; Correa Baena, J. P ; Domanski, K ; Matsui, T ; Steier, L ; Giordano, F ; Tajabadi, F ; Tress, W ; Saliba, M ; Abate, A ; Morteza Ali, A ; Taghavinia, N ; Grätzel, M ; Hagfeldt, A ; Sharif University of Technology
    Wiley-VCH Verlag  2016
    A low-cost carbon cloth is applied in perovskite solar cells (PSC) as a collector composite and degradation inhibitor. This study incorporates carbon fibers as a back contact in perovskite solar cells, which results in enhancement in all photovoltaic parameters. This material is suitable for large-scale fabrication of PSCs as it has shown an improved long-term stability when compared to the gold counterpart under elevated temperatures  

    Stability analysis of broadband cascode amplifiers in the presence of inductive parasitic components

    , Article IET Circuits, Devices and Systems ; Vol. 8, issue. 6 , November , 2014 , p. 469-477 Nikandish, G ; Yousefi, A ; Medi, A ; Sharif University of Technology
    Theoretical stability analysis of broadband cascode amplifiers at high frequencies is presented. The stability of the amplifier in the presence of parasitic inductive components is thoroughly investigated. It is shown that the stability can be improved by inserting a series resistance in the gate of common-gate device of the cascode amplifier. To ensure stability, the gate resistance should be selected within specific ranges that are derived analytically. Based on the insights provided by the analyses, several practical design guidelines are given to improve the stability of high-frequency broadband cascode amplifiers. Finally, the derived results are adopted in stabilisation of an X-band... 

    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 Tavakoli, M. M ; Si, H ; Yadav, P ; Prochowicz, D ; Tavakoli, R ; Sharif University of Technology
    Wiley-VCH Verlag  2020
    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... 

    Efficient perovskite solar cells based on Cdse/Zns quantum dots electron transporting layer with superior UV stability

    , Article Physica Status Solidi - Rapid Research Letters ; Volume 14, Issue 6 , 2020 Tavakoli, M. M ; Prochowicz, D ; Yadav, P ; Tavakoli, R ; Sharif University of Technology
    Wiley-VCH Verlag  2020
    Stability is the main challenge in the field of perovskite solar cells (PSCs). Finding new strategies is required to protect the PSCs from deteriorating agents such as humidity, heating, and illumination. Herein, a new electron transporting layer (ETL), i.e., CdSe/ZnS quantum dots (QDs), is proposed for the fabrication of efficient and stable PSCs. CdSe/ZnS QDs layer not only works as an ETL but also has downshifting property, which can improve both efficiency and stability of the PSCs. Using CdSe/ZnS QDs ETL with green emission, a PSC with maximum power conversion efficiency (PCE) of 18% is achieved. More importantly, the device shows great UV stability, much better than the device with... 

    Stability of titania nano-particles in different alcohols

    , Article Ceramics International ; Volume 38, Issue 5 , 2012 , Pages 3893-3900 ; 02728842 (ISSN) Farrokhi Rad, M ; Ghorbani, M ; Sharif University of Technology
    The alcoholic suspensions of titania nano-particles were prepared using the methanol, ethanol, isopropanol and butanol as the solvents as well as triethanolamine (TEA) as an dispersant. The colloidal stability of suspensions, both in the absence as well as presence of TEA, was studied by measuring the zeta potential, sedimentation, pH and electrical conductivity of suspensions, dispersant adsorption and particles size distribution. Results showed that in the absence of TEA, the stability of the suspensions increases with the molecular size of alcohol (from methanol to butanol), while the zeta potential decreases. It was also observed that with the addition of TEA up to the optimum dosage (4... 

    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... 

    Encapsulation strategies for highly stable perovskite solar cells under severe stress testing: damp heat, freezing, and outdoor illumination conditions

    , Article ACS Applied Materials and Interfaces ; Volume 13, Issue 38 , 2021 , Pages 45455-45464 ; 19448244 (ISSN) Mohammadi, M ; Gholipour, S ; Malekshahi Byranvand, M ; Abdi, Y ; Taghavinia, N ; Saliba, M ; Sharif University of Technology
    American Chemical Society  2021
    A key direction toward managing extrinsic instabilities in perovskite solar cells (PSCs) is encapsulation. Thus, a suitable sealing layer is required for an efficient device encapsulation, preventing moisture and oxygen ingression into the perovskite layer. In this work, a solution-based, low-cost, and commercially available bilayer structure of poly(methyl methacrylate)/styrene-butadiene (PMMA/SB) is investigated for PSCs encapsulation. Encapsulated devices retained 80% of the initial power conversion efficiency (PCE) at 85 °C temperature and 85% relative humidity after 100 h, while reference devices without SB (only PMMA) suffer from rapid and intense degradation after only 2 h, under the...