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    The effect of viscosity, applied frequency and driven pressure on the laser induced bubble luminescence in water-sulfuric acid mixtures

    , Article Physics Letters, Section A: General, Atomic and Solid State Physics ; Volume 380, Issues 27–28 , June , 2016 , Pages 2219–2226 ; 03759601 (ISSN) Sadighi Bonabi, R ; Alijan Farzad Lahiji, F ; Razeghi, F ; Sharif University of Technology
    Elsevier  2016
    Abstract
    Production and oscillation of sonoluminescence bubbles by laser pulse in the presence of acoustic field in water and different concentrations of sulfuric acid are investigated. In the presence of acoustic field, the laser causes variable speed of sound, surface tension and density; and the host liquid acts as a compressible one and strongly affects the bubble's dynamics equations. The effect of various concentrations of sulfuric acid as a host liquid on the oscillation of bubble radius, bubble wall velocity and bubble interior temperature is studied. Furthermore, the effect of applied frequency on LI-SCBL in the presence of the acoustic field is investigated and an optimum sound wave... 

    A rare type of Rhenium(I) diimine complexes with unsupported coordinated phosphine oxide ligands: Synthesis, Structural Characterization, Photophysical and theoretical study

    , Article European Journal of Inorganic Chemistry ; Volume 2019, Issue 39-40 , 2019 , Pages 4350-4357 ; 14341948 (ISSN) Nayeri, S ; Jamali, S ; Pavlovskiy, V. V ; Porsev, V. V ; Evarestov, R. A ; Kisel, K. S ; Koshevoy, I. O ; Shakirova, J. R ; Tunik, S. P ; Sharif University of Technology
    Wiley-VCH Verlag  2019
    Abstract
    This paper presents synthesis and photophysical investigation of a very rare type of the ReI diimine complexes, [Re(diimine)(CO)3(OPR3)]+, R = Ph, Cy; diimine – phenanthroline and neocuproine, containing monodentate (unsupported) phosphine oxide ligands. The obtained compounds have been structurally characterized in solid phase by using XRD crystallography, which revealed unusual distortions in the pseudo octahedral rhenium environment, which may be ascribed to intramolecular interligand (phosphine oxide – diimine) interaction rather than to crystal packing effect. Optimization of the ground state structure of these molecules with the DFT method also confirmed intramolecular origin of the... 

    Assessment of luminescent downshifting layers for the improvement of light-harvesting efficiency in dye-sensitized solar cells

    , Article ChemPhysChem ; Vol. 15, issue. 17 , 2014 , pp. 3791-3799 ; ISSN: 14394235 Hosseini, Z ; Diau, E. W. G ; Mehrany, K ; Taghavinia, N ; Sharif University of Technology
    Abstract
    Luminescence downshifting (LDS) of light can be a practical photon management technique to compensate the narrow absorption band of high-extinction-coefficient dyes in dye-sensitized solar cells (DSSCs). Herein, an optical analysis on the loss mechanisms in a reflective LDS (R-LDS)/DSSC configuration is reported. For squaraine dye (550-700 nm absorption band) and CaAlSiN3:Eu2+ LDS material (550-700 nm emission band), the major loss channels are found to be non-unity luminescence quantum efficiency (QE) and electrolyte absorption. By using an ideal LDS layer (QE=100 %), a less absorbing electrolyte (Co-based), and antireflection coatings, approximately 20% better light harvesting is obtained.... 

    Luminescent Spectral Conversion to Improve the Performance of Dye-Sensitized Solar Cells

    , Article ChemPhysChem ; Volume 18, Issue 23 , 2017 , Pages 3292-3308 ; 14394235 (ISSN) Hosseini, Z ; Taghavinia, N ; Wei Guang Diau, E ; Sharif University of Technology
    Abstract
    Relative to the broadband solar spectrum, a narrow range of spectral absorption of photovoltaic (PV) devices is considered an important determinant that the efficiency of light harvesting of these devices is less than unity. Having the narrowest spectral response to solar radiation among all PV devices, dye-sensitized solar cells (DSSCs) suffer severely from this loss. Luminescent spectral conversion provides a mechanism to manipulate and to adapt the incident solar spectrum by converting, through photoluminescence, the energies of solar photons into those that are more effectively captured by a PV device. This mechanism is particularly helpful for DSSCs because there is much flexibility in... 

    Microwave-assisted synthesis of bithiazole derivatives under solvent-free conditions

    , Article Russian Journal of Organic Chemistry ; Volume 41, Issue 4 , 2005 , Pages 623-624 ; 10704280 (ISSN) Hashemi, M. M ; Asadollahi, H ; Mostaghim, R ; Sharif University of Technology
    2005

    Role of liquid compressional viscosity in the dynamics of a sonoluminescing bubble

    , Article Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics ; Volume 70, Issue 1 , 2004 , Pages 6- ; 1063651X (ISSN) Moshaii, A ; Sadighi Bonabi, R ; Sharif University of Technology
    2004
    Abstract
    The well-known Rayleigh-Plesset [Formula presented] equation is the basis of almost all hydrodynamical descriptions of single-bubble sonoluminescence [Formula presented]. A major deficiency of the [Formula presented] equation is that it accounts for viscosity of an incompressible liquid and compressibility, separately. By removing this approximation, a new modification of the [Formula presented] equation is presented considering effect of compressional viscosity of the liquid. This modification leads to addition of a new viscous term to the traditional bubble boundary equation. Influence of this new term in the dynamics of a sonoluminescing bubble has numerically been studied considering... 

    Enhancement of Mn luminescence in ZnS:Mn multi-quantum-well structures

    , Article Applied Physics Letters ; Volume 83, Issue 22 , 2003 , Pages 4616-4618 ; 00036951 (ISSN) Taghavinia, N ; Makino, H ; Yao, T ; Sharif University of Technology
    2003
    Abstract
    The efficiency of Mn luminescence is enhanced in low-thickness ZnS:Mn layers. While various hypotheses can be considered to explain the phenomenon, it seems more reasonable to consider the luminescence enhancement effect a result of the formation of dot-like regions with higher local Mn concentration  

    Enhanced light harvesting with a reflective luminescent down-shifting layer for dye-sensitized solar cells

    , Article ACS Applied Materials and Interfaces ; Volume 5, Issue 12 , 2013 , Pages 5397-5402 ; 19448244 (ISSN) Hosseini, Z ; Huang, W. K ; Tsai, C. M ; Chen, T. M ; Taghavinia, N ; Diau, E. W. G ; Sharif University of Technology
    2013
    Abstract
    For a dye-sensitized solar cell with a near-infrared squaraine (SQ1) sensitizer, the photovoltaic performance was enhanced remarkably with a reflective luminescent down-shifting (R-LDS) layer to increase the light-harvesting efficiency at the wavelength region 400-550 nm where the SQ1 dye has weak absorption. Relative enhancements greater than 200% in IPCE near 500 nm and 40-54% in JSC were achieved with red phosphor CaAlSiN 3:Eu2+ as the LDS material, attaining 5.0 and 4.8% overall efficiencies of power conversion for the R-LDS layer coated on the counter electrode (front illumination) and working electrode (back illumination), respectively  

    Highly biocompatible multifunctional hybrid nanoparticles based on Fe3O4 decorated nanodiamond with superior superparamagnetic behaviors and photoluminescent properties

    , Article Materials Science and Engineering C ; Volume 114 , September , 2020 Salkhi Khasraghi, S ; Shojaei, A ; Sundararaj, U ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    The multifunctional nanostructures with superparamagnetic and luminescent properties undergo revolution in the field of bio-nanotechnology. In this article, we reported a facile and efficient one-step modified co-precipitation method to load superparamagnetic Fe3O4 nanoparticle on oxidized nanodiamond (Ox-ND). Subsequently, the as-prepared Ox-ND/Fe3O4 hybrid nanoparticle was surface functionalized with vinyltrimethoxysilane (VTMS) to enhance its compatibility with organic media. The structure, morphology, magnetic, and optical properties of the nanohybrid were systematically investigated. The results confirmed successful loading of crystalline Fe3O4 on the surface of Ox-ND. Ox-ND/Fe3O4... 

    Formation of Silicon Nanoparticles From Porous Silicon for LED Application

    , M.Sc. Thesis Sharif University of Technology Moeini Rizi, Mansoure (Author) ; Taghavinia, Nima (Supervisor)
    Abstract
    Semiconductor nanocrystals act as a good luminescent layer in new coming electroluminescence devices. Research on luminescent devices based on nanocrystals such as silicon nanoparticles, has been progressed over the last decades. In this research, silicon nanoparticles have been synthesized from porous silicon layer that was created through an electrochemical process. The effective luminescent parameters like electrolyte contents, current density and reaction time have been investigated. The maximum luminescence has been captured when the current density and reaction time were adjusted at 30 and 20 min, respectively. In addition, volume ratio Ethanol:HF 14:8 was another modified... 

    Self-assembled one-pot synthesis of red luminescent CdS:Mn/Mn(OH)2 nanoparticles

    , Article Journal of Luminescence ; Volume 128, Issue 12 , December , 2008 , Pages 1980-1984 ; 00222313 (ISSN) Marandi, M ; Taghavinia, N ; Iraji Zad, A ; Mahdavi, S. M ; Sharif University of Technology
    2008
    Abstract
    We report a novel method of growing red luminescent (635 nm) Mn-doped CdS (CdS:Mn) nanoparticles capped by an inorganic shell of Mn(OH)2. CdSO4, Na2S2O3 and Mn(NO3)2 were used as the precursors, and thioglycerol (C3H8O2S) was employed as the capping agent and also the catalyst of the reaction. Using these materials resulted in very slow rate of the reaction and particles growth. The self-assembled one-pot process was performed at pH of 8 and Mn:Cd ratio of 10, and took about 10 days for completion. CdS:Mn nanoparticles are slowly formed in the first day of the process; however, the luminescence is weak. After 7 days, the solution turns white turbid through the formation of additional... 

    Effect of solvent on nanostructure and luminescence properties of combustion synthesized Eu3+ doped yttria

    , Article Nanoscience and Nanotechnology Letters ; Vol. 6, issue. 8 , August , 2014 , p. 692-696 Rafiaei, S. M ; Kim, A ; Shokouhimehr, M ; Sharif University of Technology
    Abstract
    Y2 O3:Eu3+ nanostructures with bright red emitting phosphors have been synthesized by the combustion method using water and water/ethanol mixture as solvents. The effect of the solvents on nanostructure and luminescence properties of combustion synthesized Y2 O3:Eu3+ was explored. The synthesized nanostructures were calcined at 400 ° C and 1000 ° C to remove the organic phases and enhance the crystallinity. The crystal structures were characterized by an X-ray diffractometer and the particle size and morphology of the synthesized nanostructures were studies using a field emission scanning electron microscope and a transmission electron microscope. We found that the solvent choice has a... 

    Application of a dual functional luminescent layer to enhance the light harvesting efficiency of dye sensitized solar cell

    , Article Materials Letters ; 2016 ; 0167577X (ISSN) Hosseini, Z ; Taghavinia, N ; Diau, E. W. G
    Elsevier B.V  2016
    Abstract
    A luminescent coating of CaAlSiN3:Eu2+ particles applied on photoanode (TiO2) layer of SQ1 sensitized solar cell by doctor blading the paste of phosphor particles. The luminescent layer acted as a dual functional layer and enhanced the short circuit current density (JSC) by 64% via both scattering effect and downshifting of the photons in 400-600nm spectral range to photons in 600-800nm spectral range. Considerable relative enhancement in incident photon to current conversion efficiency (IPCE) up to 350% in 400-600nm spectral range proves the down shifting effect as the dominant factor for the improved performance of dye sensitized solar cell (DSSC). © 2016 Elsevier B.V  

    Application of a dual functional luminescent layer to enhance the light harvesting efficiency of dye sensitized solar cell

    , Article Materials Letters ; Volume 188 , 2017 , Pages 92-94 ; 0167577X (ISSN) Hosseini, Z ; Taghavinia, N ; Diau, E. W. G ; Sharif University of Technology
    Elsevier B.V  2017
    Abstract
    A luminescent coating of CaAlSiN3:Eu2+ particles applied on photoanode (TiO2) layer of SQ1 sensitized solar cell by doctor blading the paste of phosphor particles. The luminescent layer acted as a dual functional layer and enhanced the short circuit current density (JSC) by 64% via both scattering effect and downshifting of the photons in 400–600 nm spectral range to photons in 600–800 nm spectral range. Considerable relative enhancement in incident photon to current conversion efficiency (IPCE) up to 350% in 400–600 nm spectral range proves the down shifting effect as the dominant factor for the improved performance of dye sensitized solar cell (DSSC). © 2016 Elsevier B.V  

    CdS:Mn and CdS:O Nanoparticles Growth via Thermochemical and Microwave Methods and Studding the Photoluminescence Properties

    , M.Sc. Thesis Sharif University of Technology Amrollahi Biuki, Rezvaneh (Author) ; Taghavinia, Nima (Supervisor)
    Abstract
    The optimization of CdS photoluminescence nanoparticles which has been considered as one of the most important II-VI semiconductors has been studied here. As the first step, synthesis parameters effect on CdS:Mn photoluminescence intensity has been regarded by thermochemical method. Effect of parameters like pH solution, heating time and capping agent concentration on photoluminescence of these materials has been experimented. What seemed so important was reaching nanoparticles with suitable nano size and nano structure and having highly photoluminescence intensity. Observing the good effect of Oxygen on photoluminescence of CdS nanoparticles leaded us to concentrate on synthesizing CdS:O... 

    Investigating Process Factors on Red-shift of Photoluminescence of Carbon Dots

    , M.Sc. Thesis Sharif University of Technology Feghhi, Fazeleh (Author) ; Madah Hosseini, Hamid Reza (Supervisor)
    Abstract
    In recent years, studies in luminescent carbon dots are overgrowing, the prominent features of carbon quantum dots include cheap and straightforward synthesis, excellent biocompatibility, and adjustable optical properties. However, the widespread use of carbon dots in biomedical diagnostics, photoluminescence, and photocatalysis has been limited due to a lack of emission and excitation in the red or near-infrared region.. However, the widespread use of carbon dots in biomedical diagnostics, photoluminescence, and photocatalysis has been limited due to a lack of emission and excitation in the red or near-infrared region. This research tried to produce carbon dots with redshift in emission... 

    Sonoluminescence radiation from different concentrations of sulfuric acid

    , Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 80, Issue 4 , 2009 ; 15393755 (ISSN) Moshaii, A ; Imani, K ; Silatani, M ; Sharif University of Technology
    2009
    Abstract
    Sonoluminescence (SL) radiation from an argon bubble in water and in different concentrations of sulfuric acid has numerically been studied to quantify the effects of vapor pressure and viscosity of the liquid on cavitation luminescence in a liquid with controllable vapor pressure and viscosity. For the solutions containing the noble gas with low partial pressure (about 4 Torr), it is shown that there exists an optimum acid solution in which both the temperature and the intensity of SL radiation become maximum. The calculations show that the maximum SL radiation is achieved from the solution of around 65% (wt.) H2 SO4, which is in agreement with available experimental results. © 2009 The... 

    The two-step thermochemical growth of ZnS:Mn nanocrystals and a study of luminescence evolution

    , Article Nanotechnology ; Volume 20, Issue 9 , 2009 ; 09574484 (ISSN) Hajisalem, G ; Marandi, M ; Taghavinia, N ; Houshiar, M ; Sharif University of Technology
    2009
    Abstract
    In this work we report a new thermochemical method for the synthesis of ZnS:Mn nanocrystals. Zn(NO3)2 and Na2S 2O3 were used as the precursors and Mn(NO 3)2 was the source of impurity. Thioglycerol (TG,C 3H8O2S) was also used as the capping agent and the catalyst of the reaction. Na2S2O3 is a heat sensitive material which releases S species upon heating. Consequently, the reaction proceeds in temperatures higher than room temperature. The reaction was done in two steps. In the first step, the precursors were heated at 96 °C for an hour without TG. In the second step, TG was injected to the solution and the heating process was continued for longer heating durations. A fast growth occurred in... 

    Optical nanoprobes for chiral discrimination

    , Article Analyst ; Volume 145, Issue 20 , 2020 , Pages 6416-6434 Bigdeli, A ; Ghasemi, F ; Fahimi Kashani, N ; Abbasi Moayed, S ; Orouji, A ; Jafar Nezhad Ivrigh, Z ; Shahdost Fard, F ; Hormozi Nezhad, M. R ; Sharif University of Technology
    Royal Society of Chemistry  2020
    Abstract
    Chiral discrimination has always been a hot topic in chemical, food and pharmaceutical industries, especially when dealing with chiral drugs. Enantiomeric recognition not only leads to better understanding of the mechanism of molecular recognition in biological systems, but may further assist in developing useful molecular devices in biochemical and pharmaceutical studies. By emerging nanotechnology and exploiting nanomaterials in sensing applications, a great deal of attention has been given to the design of optical nanoprobes that are able to discriminate enantiomers of chiral analytes. This review explains how engineering nanoparticles (NPs) with desired physicochemical properties allows... 

    Highly sensitive selective sensing of nickel ions using repeatable fluorescence quenching-emerging of the CdTe quantum dots

    , Article Materials Research Bulletin ; Volume 95 , 2017 , Pages 532-538 ; 00255408 (ISSN) Zare, H ; Ghalkhani, M ; Akhavan, O ; Taghavinia, N ; Marandi, M ; Sharif University of Technology
    Abstract
    Highly sensitive nickel sensor based on repeatable fluorescence quenching-emerging mechanism was developed. Highly luminescent thioglycolic acid capped CdTe nanocrystals in aqueous solution were applied as the fluorescence probe. These nanocrystals represented a considerable photoluminescence quantum yield as high as 61%. The florescence was quenched by addition of Ni ions to the CdTe nanocrystals solution. Then it was recovered by injection of the proper amount of dimethylglyoxime as the releasing reagent. The relative fluorescence intensity (F0/F) was linearly proportional to the concentration of nickel ions in the range of 0.01–10 μM, with detection limit as low as 7 nM. Described method...