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    Manipulation of Electronic Structure in Boron Nitride Nanosheets to Improve Catalytic and Photocatalytic Properties

    , M.Sc. Thesis Sharif University of Technology Hemmati, Amir (Author) ; Simchi, Abdolreza (Supervisor)
    Abstract
    The variety of 2D materials and their wide range of properties, as well as numerous methods to manipulate them, have made this class of materials among prominent candidates for the future of the energy industry. Among the means available to tailor nanomaterials performance for such applications, introducing dopants and the creation of heteroatom-doped structures are of great interest. In this study, mixtures of urea, boric acid, and graphene oxide, as cheap and available precursors, were used to synthesize C-doped h-BN nanosheets. After the implementation of TGA/DSC to select a suitable calcination temperature of 950 C°, the samples were successfully synthesized with relatively precise... 

    Design and Construction of Fluorescent Confocal Microscopy Setup for Detection of Single Photon Emitters in 2d Materials

    , M.Sc. Thesis Sharif University of Technology Ebrahimi, Abolfazl (Author) ; Esfandiar, Ali (Supervisor)
    Abstract
    The main goal of this research is to detect and characterize single-photon emitters in two-dimensional hexagonal boron nitride crystal with the help of fluorescence confocal microscope and Hanbury-Brown and Twiss interferometer. The origin of single-photon radiation in this crystal is not precisely known. It seems that the transition between energy levels, which occurs due to the presence of point defects in the crystal structure of this material, in the distance between the conduction and valence bands, is the source of single-photon radiation. This material does not require low temperature for single-photon radiation, which is an important advantage for it. In a confocal microscope, the... 

    Review - Towards the two-dimensional hexagonal boron nitride (2D h-BN) electrochemical sensing platforms

    , Article Journal of the Electrochemical Society ; Volume 167, Issue 12 , 2020 Angizi, S ; Khalaj, M ; Alem, S. A. A ; Pakdel, A ; Willander, M ; Hatamie, A ; Simchi, A ; Sharif University of Technology
    IOP Publishing Ltd  2020
    Abstract
    Electrochemical sensing performance of two-dimensional hexagonal boron nitride (2D h-BN) has traditionally been suppressed by their intrinsic electrical insulation and deficient electron transportation mechanism. However, the excellent electrocatalytic activity, high specific surface area, N- and B-active edges, structural defects, adjustable band gap through interaction with other nanomaterials, and chemical functionalization, makes 2D h-BN ideal for many sensing applications. Therefore, finding a pathway to modulate the electronic properties of 2D h-BN while the intrinsic characteristics are well preserved, will evolve a new generation of highly sensitive and selective electrochemical... 

    Plasma surface functionalization of boron nitride nano-sheets

    , Article Diamond and Related Materials ; Volume 77 , 2017 , Pages 110-115 ; 09259635 (ISSN) Achour, H ; Achour, A ; Solaymani, S ; Islam, M ; Vizireanu, S ; Arman, A ; Ahmadpourian, A ; Dinescu, G ; Sharif University of Technology
    Elsevier Ltd  2017
    Abstract
    On silicon substrates, boron nitride nanosheets (BNNS) consisting of interconnected hexagonal boron nitride nano-layers were produced via chemical vapor deposition process at 1200 °C whose roughness's are at the micrometer- and nanometer-scale. The BNNS were functionalized in argon plasma admixed with ammonia or nitrogen or oxygen. The samples were characterized to investigate the surface chemistry and structural changes after plasma treatment using X-ray photoelectron spectroscope and Micro-Raman spectroscope techniques, respectively. While no significant changes in the surface features, upon plasma treatments of the BNNS, were noticed during SEM and TEM examination, the oxygen functional... 

    Effect of mono-vacant defects on the opto-electronic properties of ionic liquid functionalized hexagonal boron-nitride nanosheets

    , Article Journal of Molecular Liquids ; Volume 249 , 2018 , Pages 1172-1182 ; 01677322 (ISSN) Shakourian Fard, M ; Bayat, A ; Kamath, G ; Sharif University of Technology
    Abstract
    We compare and contrast the physisorption behavior of imidazolium and butyltrimethylammonium based ionic liquids (ILs) on mono-vacant nitrogen and boron defective hexagonal boron nitride nanoflakes (h-BNNF) using M06-2X/cc-pVDZ level of theory. The presence of defects on the nanoflakes results in an increase in IL binding energy by ~ 1–27 kcal/mol partly due to the lowering of the energy band in the defective nanoflakes. Imidazolium based ILs adsorb energetically more favorably on h-BNNF-VB than on h-BNNF-VN while butyltrimethylammonium based ILs prefer to adsorb on h-BNNF-VN. Upon adsorption of imidazolium ILs on the nanoflakes, an increase in both HOMO and LUMO orbital energies is observed... 

    Superhydrophobic and thermally conductive carbon black/hexagonal boron nitride@Fe3O4/cellulose composite paper for electromagnetic interference shielding

    , Article Synthetic Metals ; Volume 285 , 2022 ; 03796779 (ISSN) Habibi, N ; Pourjavadi, A ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    Herein, a series of superhydrophobic thin polyacrylic resin-coated carbon black (CB)/hexagonal boron nitride (h-BN)@Fe3O4/cellulose composite papers with good flexibility, low density (~0.67 g/cm3), high electrical conductivity (~0.065 S/cm), good thermal conductivity (0.462 W.m−1. K−1), and with water contact angle (WCA) of 153° were successfully fabricated by a facile dip-coating/spraying method. The CB-BN@Fe3O4 distribution in cellulose matrix provided high electrical conductivity in the in-plane and thickness directions. The electrical conductivity in both in-plane and thickness directions increased by increasing the number of vacuum-assisted dip-coating cycles. Moreover, these... 

    Mechanism of the motion of nanovehicles on hexagonal boron-nitride: A molecular dynamics study

    , Article Computational Materials Science ; Volume 207 , 2022 ; 09270256 (ISSN) Vaezi, M ; Nejat Pishkenari, H ; Nemati, A ; Sharif University of Technology
    Elsevier B.V  2022
    Abstract
    Nanocars have been proposed to transport nanomaterials on the surface. Study of the mechanism of the motion of nanocars has attracted a lot of interests due to the potential ability of these nano-vehicles in the construction of nanostructures with bottom-up approach. Using molecular dynamics simulations, we study the motion of two nano-vehicles named “Nanocar” and “Nanotruck” on hexagonal boron-nitride monolayer. The obtained results reveals that, boron-nitride is an appropriate option to obtain higher mobility of nanocars compared with metal substrates. Considering different temperatures reveals that nanocars start to move on the BN at 200 K, while long range motions are observed at 400 K... 

    Thermally conductive and superhydrophobic polyurethane sponge for solar-assisted separation of high-viscosity crude oil from water

    , Article ACS Applied Materials and Interfaces ; Volume 14, Issue 5 , 2022 , Pages 7329-7339 ; 19448244 (ISSN) Habibi, N ; Pourjavadi, A ; Sharif University of Technology
    American Chemical Society  2022
    Abstract
    The rapid and effective separation of high-viscosity heavy crude oil from seawater is a worldwide challenge. Herein, an ultralow density, photothermal, superhydrophobic, and thermally conductive polyurethane/polyaniline/hexagonal boron nitride@Fe3O4/polyacrylic-oleic acid resin sponge (PU/PANI/h-BN@Fe3O4/AR) was fabricated with a water contact angle (WCA) of 158°, thermal conductivity of 0.76 W m-1 K-1, density of 0.038 g cm-3, limited oxygen index (LOI) of 28.82%, and porosity of 97.97% and used for solar-assisted separation of high-viscosity crude oil from water. Photothermal components were composed of PANI and Fe3O4, while h-BN particles were used as thermally conductive and flame...