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    Electrocatalytic oxidation of thioglycolic acid at carbon paste electrode modified with cobalt phthalocyanine: Application as a potentiometric sensor

    , Article Electrochimica Acta ; Volume 48, Issue 28 , 2003 , Pages 4143-4148 ; 00134686 (ISSN) Shahrokhian, S ; Yazdani, J ; Sharif University of Technology
    The voltammetric behavior of thioglycolic acid (TGA) was studied at a carbon paste electrode modified with cobalt phthalocyanine (CoPc). The CoPc-modified electrode shows high electrocatalytic activity toward oxidation of TGA, lowering substantially the overpotential of anodic reaction. Results of the cyclic voltammetry show that TGA undergoes a two-step oxidation (each step with one electron) resulting the dimer of thiol. Enhancement of the rate of electron transfer results in a near-Nernstian behavior of modified electrode to the concentration of TGA and makes it as a suitable potentiometric sensor for the detection of this compound. This electrode shows a near-Nernstian response in a wide... 

    Synthesis of ZnCdS Luminescent Nanoparticles for Hybrid Light Emitting Diode

    , M.Sc. Thesis Sharif University of Technology Alehdaghi, Hassan (Author) ; Taghavinia, Nima (Supervisor) ; Irajizad, Azam (Supervisor)
    In recent decade energy crisis causes research on luminescent devises gains special importance. Particularly, hybrid LEDs (organic- nanocrystal) have been studied by a number of researches due to their advantages. Easy fabrication and narrow spectrum of radiation are mentioned as the most important benefits. The emissive layer is the most important part in these diodes which made of semiconductor nanoparticles. There are a variety of chemical methods for synthesis of semiconductor nanoparticles. We focus on aqueous method for nanoparticles synthesis because of its advantages. Alloyed semiconductor nanoparticles of ZnxCd1-xS were selected for this research work. The manifest features of the... 

    Design of a ratiometric fluorescent probe for naked eye detection of dopamine

    , Article Analytical Methods ; Volume 9, Issue 23 , 2017 , Pages 3505-3512 ; 17599660 (ISSN) Farahmand Nejad, M. A ; Hormozi Nezhad, M. R ; Sharif University of Technology
    A simple and effective ratiometric fluorescence sensor for selective detection of dopamine (DA) in alkaline media has been developed by simply mixing thioglycolic acid (TGA) functionalized orange fluorescent cadmium telluride (CdTe) quantum dots (QDs) with amino-functionalized blue fluorescent carbon nanodots (CDs). Under a single excitation wavelength of 365 nm, the sensor exhibits dual-emissions centered at 445 and 603 nm. The fluorescence of CdTe QDs is selectively quenched by DA, whereas the fluorescence of CDs is insensitive to the analyte. In the presence of different amounts of DA, the variations in the dual emission intensity ratios exhibit a continuous color change from pink to... 

    Interstitial sulfur photoluminescence in thermochemically synthesized CdS nanocrystals (NCs)

    , Article EPJ Applied Physics ; Volume 56, Issue 1 , 2011 ; 12860042 (ISSN) Molaei, M ; Saievar Iranizad, E ; Marandi, M ; Taghavinia, N ; Sharif University of Technology
    We have synthesized CdS NCs (NCs) by a thermochemical approach. CdSO 4 and Na2S2O3 were used as the precursors and thioglycolic acid (TGA) was used as capping agent molecule. The structure and optical property of the NCs were characterized by means of XRD, TEM, UV-visible optical spectroscopy and photoluminescence (PL). XRD and TEM analyses demonstrated hexagonal phase CdS NCs with an average size of around 2 nm. Synthesized NCs exhibited a band gap of about 3.21 eV and showed a broad band emission from 400 to 750 nm centered at 503 nm. This broad band emission is related to surface states of CdS and our results showed that the emission peak can be attributed to the interstitial sulfur. The... 

    Synthesis of CdS nanocrystals by a microwave activated method and investigation of the photoluminescence and electroluminescence properties

    , Article Applied Surface Science ; Volume 257, Issue 23 , September , 2011 , Pages 9796-9801 ; 01694332 (ISSN) Molaei, M ; Iranizad, E. S ; Marandi, M ; Taghavinia, N ; Amrollahi, R ; Sharif University of Technology
    We have synthesized CdS nanocrystals (NCs) by a microwave activated method. CdSO4 and Na2S2O3 were used as the precursors and thioglycolic acid (TGA) was used as capping agent molecule. The aqueous synthesis was based on the heat sensitivity of Na2S 2O3. In this method, microwave irradiation creates the activation energy for dissociation of Na2S2O3 and leads to the CdS NCs formation. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses demonstrated hexagonal phase CdS NCs with an average size around 3 nm for sample prepared at 5 min irradiation time. A band gap range of 3.38-2.89 eV was possible only by increasing the microwave irradiation time, corresponding to a...