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    Dispute in photocatalytic and photoluminescence behavior in ZnO/graphene oxide core-shell nanoparticles

    , Article Materials Letters ; Volume 240 , 2019 , Pages 117-120 ; 0167577X (ISSN) Haghshenas, S. S. P ; Nemati, A ; Simchi, A ; Kim, C. U ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    ZnO/graphene oxide core-shell nanoparticles (ZGNPs) were prepared by via in-situ chemical synthesis and electrolysis. This report addresses the disagreement in the photocatalytic and photoluminescence behavior in this system. XRD, Raman, HRTEM, PL and UV–Vis were able to confirm ZnO nanoparticles and core-shell structures formation at various temperatures. A little shift was observed in Raman for ZGNPs after conjugating. PL showed a few peaks that were not related to the graphene, which depends on the synthesis route and defects. After conjugating between ZnO and Graphene, two mechanisms are suggested. The first is band structure modification in the boundary of core and shell. The second one... 

    Nanomaterial-assisted pyrolysis of used lubricating oil and fuel recovery

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; 2020 Alavi, E ; Abdoli, M. A ; Khorasheh, F ; Nezhadbahadori, F ; Bayandori Moghaddam, A ; Sharif University of Technology
    Taylor and Francis Inc  2020
    Abstract
    Used lubricating oil (ULO) is a heavy mixture of various hydrocarbons and needs to be treated before discharging. Considering ULO nature, it is more favorable to recover lighter hydrocarbon cuts from ULO, which not only improves the whole process economically, but also prevents the emission of hardly decomposable hydrocarbons into the environment. In this research, the potential of pyrolysis method for ULO recovery was studied. Furthermore, graphene nanoplatelets (GNP), γ- Fe2O3 and ZnO nanoparticles were used to improve the kinetics of the process and their impacts on the final product quality were evaluated. Based on the results, adding nanomaterials increased the tendency to produce gas... 

    All-spray multilayer transparent electrode based on Ag nanowires: improved adhesion and thermal/chemical stability

    , Article Journal of Materials Science: Materials in Electronics ; Volume 31, Issue 17 , 2020 , Pages 14078-14087 Amiri Zarandi, A ; Khosravi, A ; Dehghani, M ; Taghavinia, N ; Sharif University of Technology
    Springer  2020
    Abstract
    All-solution-processed multilayer ZnO/Ag NWs/ZnO/PVP/PVA composite is introduced as a transparent conductive film (TCF) for optoelectronic applications. Unlike conventional film formation methods that impose high investment expenses, scalable spray coating is applied over the layers using a hand-made spray apparatus. The resulting TCF exhibits high transmittance (T, 86% at 550 nm) and low sheet resistance (Rs, 6 Ω/sq), which is comparable to the sputtered counterparts. The bending test demonstrates the flexibility of the multilayer TCF with no noticeable increase in Rs, even after 1500 bending iterations. Moreover, chemical stability test (exposure to a corrosive agent) and adhesion... 

    A smart-phone based ratiometric nanoprobe for label-free detection of methyl parathion

    , Article Sensors and Actuators, B: Chemical ; Volume 322 , 2020 Fahimi Kashani, N ; Hormozi Nezhad, M. R ; Sharif University of Technology
    Elsevier B.V  2020
    Abstract
    The widespread use of pesticides in pest management has boosted the demands for developing highly sensitive probes for on-site monitoring. Herein we presented a sensitive enzyme-free ratiometric probe for determination of methyl parathion (MP), as an organophosphate pesticide using TGA-capped CdTe QDs and carbon dots (CDs). Unlike previous methods in which hydrolysis product of MP is instrumental in the response of the sensors, here, self-assembly of cetyltrimethylammonium bromide (CTAB) on the surface of non-modified yellow-emissive CdTe QDs facilitates the quenching of CTAB-QDs upon addition of MP while the fluorescence intensity of CDs remains constant. Using a smartphone, the ratiometric... 

    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
    Abstract
    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... 

    Sustainable superhydrophobic branched hierarchical ZnO nanowires: Stability and wettability phase diagram

    , Article Applied Surface Science ; Volume 561 , 2021 ; 01694332 (ISSN) Ebrahimi, M ; Bayat, A ; Rahemi Ardekani, S ; Saievar Iranizad, E ; Zaker Moshfegh, A ; Sharif University of Technology
    Elsevier B.V  2021
    Abstract
    Stability of Cassie-Baxter (CB) state is very critical in application of superhydrophobic surfaces. The most industrial applications of superhydrophobic surfaces are limited by the transition from the CB state to Wenzel (W) state. In this research, CB state stability of branched hierarchical ZnO nanowires (BH-ZnO NWs) was investigated as compared with ZnO nanowires (ZnO NWs) by using theoretical and experimental approaches. For this purpose, surface of the BH-ZnO NWs and ZnO NWs were modified by thin layers of methyltrimethoxysilane (MTMS). The MTMS thickness was optimized by varying NH4F (0, 5, 10, 20 μL) as used catalyst. The highest water contact angle (WCA) was measured at about 153 ± 3°... 

    Visual recognition of tryptophan enantiomers using chiral self assemblies of quantum dots

    , Article ACS Applied Nano Materials ; 2021 ; 25740970 (ISSN) Fahimi Kashani, N ; Jafar Nezhad Ivrigh, Z ; Bigdeli, A ; Hormozi Nezhad, M.R ; Sharif University of Technology
    American Chemical Society  2021
    Abstract
    Discrimination of chiral targets is generally achieved with chiral nanomaterials. However, the limited number of intrinsic chiral nanostructures as well as their complex synthesis procedure has led to the production of chirality-induced nanomaterials as alternatives. Chirality can be induced in nanomaterials by either chirality transfer or the formation of chiral assemblies. Using the latter approach, in this work, we have provided chiral supramolecular assemblies of CdTe quantum dots (QDs) from achiral starting materials. CTAB-QD assemblies showed chiroptical activities, and their orange emission in combination with the blue emission of carbon dots was utilized as a ratiometric chiral... 

    Investigation of the gamma-ray shielding performance of the B2O3-Bi2O3-ZnO-Li2O glasses based on the monte carlo approach

    , Article Radiation Physics and Chemistry ; Volume 189 , 2021 ; 0969806X (ISSN) Asadi, A ; Hosseini, A ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    The purpose of this article is to investigate the shielding performance of the B2O3-Bi2O3-ZnO-Li2O glasses against the gamma-ray. To this end, the attenuation parameters of the gamma-ray inside the B2O3-Bi2O3-ZnO-Li2O glasses were evaluated in the energy range of 200–1500 keV. It was found that the mass attenuation coefficient of the composites increases with increasing the Li2O content. The relative percent deviation between the results of simulation using the MCNPX and XCOM database in most cases was less than 2%. Additionally, the Mean Free Path (MFP) and Half-Value Layer (HVL) parameters were evaluated, and the shielding efficiency of samples was compared with some conventional shielding... 

    Visual recognition of tryptophan enantiomers using chiral self assemblies of quantum DOTS

    , Article ACS Applied Nano Materials ; Volume 5, Issue 1 , 2022 , Pages 1460-1471 ; 25740970 (ISSN) Fahimi-Kashani, N ; Jafar Nezhad Ivrigh, Z ; Bigdeli, A ; Hormozi Nezhad, M. R ; Sharif University of Technology
    American Chemical Society  2022
    Abstract
    Discrimination of chiral targets is generally achieved with chiral nanomaterials. However, the limited number of intrinsic chiral nanostructures as well as their complex synthesis procedure has led to the production of chirality-induced nanomaterials as alternatives. Chirality can be induced in nanomaterials by either chirality transfer or the formation of chiral assemblies. Using the latter approach, in this work, we have provided chiral supramolecular assemblies of CdTe quantum dots (QDs) from achiral starting materials. CTAB-QD assemblies showed chiroptical activities, and their orange emission in combination with the blue emission of carbon dots was utilized as a ratiometric chiral... 

    Studies of Ponceau 4R food colorant and zinc oxide nanoparticles containing it interactions with DNA and evaluation of their antimicrobial activity

    , Article Journal of Food Processing and Preservation ; Volume 46, Issue 2 , 2022 ; 01458892 (ISSN) Zangeneh Monfared, F ; Shahabadi, N ; Mahmoudi Hashemi, M ; Meibodi, F. S ; Mirjafari, Z ; Sharif University of Technology
    John Wiley and Sons Inc  2022
    Abstract
    The current study describes design and synthesis of silica-coated zinc oxide nanoparticles containing Ponceau 4R food colorant (named as ZnO@SiO2@APTMS/P4R). The interactions of Ponceau 4R and ZnO@SiO2@APTMS/P4R with calf thymus-DNA were investigated It should be noted that the competitive binding experiment revealed that both Ponceau 4R and ZnO@SiO2@APTMS/P4R could release Hoechst 33258. As inferred from the results the binding of the Ponceau 4R and ZnO@SiO2@APTMS/P4R with DNA were surface binding, mainly due to groove binding. Furthermore, antibacterial properties of ZnO, Ponceau 4R and ZnO@SiO2@APTMS/P4R samples against gram-positive bacteria and gram-negative bacteria were examined and... 

    Persistent quantum coherence and strong coupling enable fast electron transfer across the cds/tio2 interface: a time-domain ab initio simulation

    , Article Journal of Physical Chemistry C ; Volume 122, Issue 44 , 2018 , Pages 25606-25616 ; 19327447 (ISSN) Mehdipour, H ; Akimov, A. V ; Jankowska, J ; Rezakhanai, A. T ; Tafreshi, S. S ; De Leeuw, N. H ; Moshfegh, A. Z ; Prezhdo, O. V ; Sharif University of Technology
    American Chemical Society  2018
    Abstract
    Fast transfer of photoinduced electrons and subsequent slow electron-hole recombination in semiconductor heterostructures give rise to long-lived charge separation which is highly desirable for photocatalysis and photovoltaic applications. As a type II heterostructure, CdS/TiO2 nanocomposites extend the absorption edge of the light spectrum to the visible range and demonstrate effective charge separation, resulting in more efficient conversion of solar energy to chemical energy. This improvement in performance is partly explained by the fact that CdS/TiO2 is a type II semiconductor heterostructure and CdS has a smaller energy band gap than UV-active TiO2. Ultrafast transient absorption... 

    Modeling the detection efficiency in photodetectors with temperature-dependent mobility and carrier lifetime

    , Article Superlattices and Microstructures ; Volume 122 , 2018 , Pages 557-562 ; 07496036 (ISSN) Moeini, I ; Ahmadpour, M ; Mosavi, A ; Alharbi, N ; Gorji, N. E ; Sharif University of Technology
    Abstract
    We proposed a modeling procedure to calculate the impact of temperature on the detection efficiency in photodetectors based on CdTe materials. Temperature increase impacts on the electrical properties of the materials such as carrier mobility and carrier recombination lifetime. This impact which can be effective in some cases has been normally ignored in the modeling approaches presented in the literature. Here we show that increasing the temperature from 190 K to 300 K not reduces the mobility of both electrons and holes but also significantly reduces the carrier lifetime. The result will impact on electric-field within the depletion width of the device, drift and diffusion lengths which... 

    Preparation and characterization of a new CdS–NiFe2O4/reduced graphene oxide photocatalyst and its use for degradation of methylene blue under visible light irradiation

    , Article Research on Chemical Intermediates ; Volume 44, Issue 10 , 2018 , Pages 5953-5979 ; 09226168 (ISSN) Bagherzadeh, M ; Kaveh, R ; Ozkar, S ; Akbayrak, S ; Sharif University of Technology
    Abstract
    In this paper, CdS nanoparticles as a visible light active photocatalyst were coupled by NiFe2O4 and reduced graphene oxide (rGO) to form CdS–NiFe2O4/rGO nanocomposite by facile hydrothermal methods. The CdS–NiFe2O4/rGO nanocomposite shows enhanced photocatalytic activity for the degradation of methylene blue (MB) under visible light illumination. In addition to improved photocatalytic performance, this prepared nanocomposite shows increased photostability and is magnetically separable from the aqueous media. The degradation rate constant (kapp) of the optimized photocatalyst, i.e. CdS–NiFe2O4 (0.05)/rGO 25 wt% nanocomposite, was higher than the corresponding CdS and NiFe2O4 nanoparticles by... 

    Shed light on submerged DC arc discharge synthesis of low band gap gray Zn/ZnO nanoparticles: Formation and gradual oxidation mechanism

    , Article Advanced Powder Technology ; Volume 29, Issue 5 , 2018 , Pages 1246-1254 ; 09218831 (ISSN) Ziashahabi, A ; Poursalehi, R ; Naseri, N ; Sharif University of Technology
    Elsevier B.V  2018
    Abstract
    Synthesis of colloidal metal oxides with controllable size and morphology is burgeoning field of research in nanoscience. Low band gap gray Zn/ZnO colloidal nanoparticles were fabricated by plasma-liquid interaction of DC arc discharge in water. Scanning electron microscopy, X-ray diffraction and UV–vis spectroscopy were employed for morphology, crystal structure and optical characterizations respectively. Optical emission spectroscopy was used to investigate the plasma properties during the synthesis and formation mechanism of nanoparticles. Nanoparticles with different size and shape were fabricated only by adjusting discharge current during synthesis without introducing any chemical... 

    Synthesis photocatalytic TiO2/ZnO nanocomposite and investigation through anatase, wurtzite and ZnTiO3 phases antibacterial behaviors

    , Article Journal of Nano Research ; Volume 51 , 2018 , Pages 69-77 ; 16625250 (ISSN) Mohammadi, H ; Ghorbani, M ; Sharif University of Technology
    Trans Tech Publications Ltd  2018
    Abstract
    Titanium dioxide is prepared by sol gel method from titanium tetraisopropoxide (TTIP) as precursor and likewise zinc oxide is prepared by sol gel method from zinc acetate dehydrate (ZAD) as precursor. The composite sols are prepared in three different molar ratios 90TiO2:10ZnO, 70TiO2:30ZnO and 50TiO2:50ZnO. Thin film deposition is carried out by dip coating technique. Crystal structure, surface morphology and photocatalytic activity of the prepared nanocomposite thin films are investigated. The antibacterial activity of the prepared nanocomposite thin film against E-coli ATCC 25922 bacteria is examined by placing the thin film in standard aqueous E-coli medium under UV light for 1, 2, 3 and... 

    Synthesis and characterization of photocatalytically active crumpled-shape nanocomposites of nitrogen and sulfur co-doped ZnO–CeO2

    , Article Solar Energy Materials and Solar Cells ; Volume 203 , 2019 ; 09270248 (ISSN) Rahemi Ardekani, S ; Sabour Rouh Aghdam, A ; Nazari, M ; Bayat, A ; Saievar Iranizad, E ; Najafi Liavali, M ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    In this study, crumpled-shape nanocomposite of nitrogen and sulfur co-doped ZnO–CeO2 (NSZC) was deposited on FTO substrate using one-step ultrasonic spray pyrolysis. Zinc acetate, cerium nitrate, and thiourea were dissolved in deionized water and used as starting solution. The samples were characterized using FESEM, XRD, UV–vis spectroscopy, EIS, and PL. The as-prepared nitrogen and sulfur co-doped ZnO–CeO2 nanocomposites were evaluated as high photocatalysts for degradation of methyl orange. Nearly 100% photocatalytic degradation of methyl orange was achieved for 180 min. The photoluminescence and electrochemical impedance spectroscopy revealed that co-doping of nitrogen and sulfur could... 

    A Rapid synthesis of vertically aligned taper-like k-doped zno nanostructures to enhance dye-sensitized solar cell efficiency

    , Article JOM ; Volume 71, Issue 12 , 2019 , Pages 4850-4856 ; 10474838 (ISSN) Sharifi Miavaghi, A ; Musavi, M ; Nanchian, H ; Pezeshkzadeh, S. A ; Sharif University of Technology
    Springer  2019
    Abstract
    Large-scale K-doped ZnO nanotapers were successfully grown on an indium tin oxide (ITO) substrate using a facile electrochemical route. The structural and morphologic analysis exhibited that the K-doped ZnO nanostructures had a nanotaper morphology and strong preferential [0001] c-axis direction with a hexagonal polycrystalline structure. The optical results show that the incorporation of K+ ions as the donors in a ZnO lattice leads to substantial modulation of the band gap structure of ZnO nanotapers, which results in a redshift in the ultraviolet emission peaks. The considerable enhancement of performance in K-doped ZnO-based dye-sensitized solar cells (DSSCs) can be related to the doping... 

    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) Saki, Z ; 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... 

    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
    Abstract
    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... 

    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) Mohamadkhani, F ; 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...