e) 2021 - 79 Documents

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Author: search.filters.author.Balavijayalakshmi, J

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    ROLE OF GRAPHENE OXIDE/YTTRIUM OXIDE NANOCOMPOSITES AS A CATHODE MATERIAL FOR NATURAL DYE-SENSITIZED SOLAR CELL APPLICATIONS
    (Wiley, 2021) Shanmugapriya, T; Balavijayalakshmi, J
    Natural dye-sensitized solar cells (DSSCs) are becoming promising candidates for replacing synthetic dyes. Graphene oxide is prepared from natural graphite flakes by modified Hummers method. A novel graphene oxide/yttrium oxide (GO/Y2O3) nanocomposites are prepared by chemical precipitation method. The different concentration of (5:1, 5:2, and 5:3) of yttrium oxide nanoparticles exaggerated on the surface of graphene oxide nanosheets. The prepared nanocomposites are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectroscopy (EDAX), Fourier transform infrared spectroscopy (FT-IR), Raman scattering spectroscopy and ultraviolet–visible (UV–vis) absorption spectroscopy. The XRD analysis showed that the crystallite size of the GO/Y2O3 (5:1, 5:2, and 5:3) is found to be around 23, 25.2, and 26.92 nm. Field emission scanning electron microscopy (FE-SEM) revealed that the flakes like shaped yttrium oxide nanoparticles are uniformly dispersed on the surface of GO sheets. The UV–vis studies showed that the prepared Jasminoum grandiflorum L (JG) dye belongs to chlorophyll group with the absorption of 4.2 eV. The electrochemical activity of the prepared nanocomposites is investigated by cyclic voltammetry (CV) technique. The power conversion efficiency of prepared sandwich type DSSCs (5:3) is found to be 1.67%.
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    MICROWAVE ASSISTED SYNTHESIS OF MOS2/PANI/ZNO NANOCOMPOSITES AS A WORKING ELECTRODE FOR ENERGY STORAGE APPLICATIONS
    (Asian Journal of Chemistry, 2021-06-26) Balavijayalakshmi, J; Krithika, S
    Transition metal dichalcogenide and polyaniline doped zinc oxide nanocomposites influence the transition probabilities and electronic structure. In present study, the various concentrations of MoS2/PANI/ZnO nanocomposites are synthesized by microwave assisted method. These nanocomposites are characterized by using XRD, FESEM, HRTEM and FT-IR. The XRD results revealed an average crystallite size of synthesized nanocomposites, which was found to be 19-24 nm. The electrochemical properties of the nanocomposites are studied through the CV, EIS and GCD for the application of supercapacitor as an active electrode material. The MoS2/PANI/ZnO nanocomposites exhibited a specific capacitance of 577 F g-1 and also retained 90% of its initial specific capacitance even after 5000 cycles. Hence MoS2/PANI/ZnO nanocomposites have potential application for energy storage applications.
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    EFFICIENCY STUDIES OF GALINSOGA PARVIFLORA PIGMENTS AS A SENSITIZER IN PT FREE GRAPHENE OXIDE/NICKEL OXIDE COUNTER ELECTRODE: DYE SENSITIZED SOLAR CELL APPLICATIONS
    (Springer Link, 2021) Shanmugapriya, T; Balavijayalakshmi, J
    An easily available Galinsoga Parviflora (GP) natural dye has been used as natural sensitizers for dye sensitized solar cell (DSSC). Graphene oxide (GO) is one of the most efficient materials for solar cells, supercapacitor and sensing applications because of its unique properties. It is prepared from natural graphite flakes by modified Hummer’s method. Graphene oxide/nickel oxide (GO/NiO) nanocomposites are prepared by chemical precipitation method. The different concentrations of nickel oxide nanoparticles (5:1, 5:2 and 5:3) are embellished on the GO surface. The synthesis of these nanocomposites are confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HR-TEM). The XRD results confirmed that the nickel oxide nanoparticles are coated on the graphene oxide surface and the crystallite size of GO/NiO (5:1, 5:2 and 5:3) nanocomposites are found to be around 19 nm, 21.3 nm and 23 nm respectively. The electrochemical activity of the prepared nanocomposites is investigated by cyclic voltammetry (CV) technique. The power conversion efficiency is measured using a light source simulated with an intensity of 100 mW/cm2. The conversion efficiency of prepared sandwich type dye sensitized solar cell (5:1, 5:2 and 5:3) is 0.9%, 1.3% and 1.65% respectively.
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    IMPACT OF IRON DOPING ON STRUCTURAL AND OPTICAL PROPERTIES OF NICKEL SULPHIDE NANOPARTICLES
    (ScienceDirect, 2021) Balavijayalakshmi, J; Sonia, D
    Transition metal sulphides exhibit excellent optical, photo electrical and thermoelectric properties. These materials have attracted much attention because of its applications in the field of electroluminescence devices, light emitting displays, cathode material for rechargeable lithium battery, magnetic devices, dye degradation and optical sensors. In the present work, iron doped Nickel sulphide nanoparticles are synthesized using chemical precipitation method. Nickel chloride and Ferric chloride are used as precursors and sodium sulphide as a stabilizing agent. The performance of the synthesized nanoparticles are analysed by varying the molarity of the iron chloride from 0.01 M to 0.05 M. The synthesized nanoparticles are characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Ultraviolet Visible spectroscopy (UV–Vis) and Photoluminescence (PL) studies. FT-IR spectral analysis shows the band at 630 cm−1 corresponds to the bending vibration of metal sulphur bond (Ni-S) and the bands observed around 585 cm−1 and 456 cm−1 are ascribed to Fe–O stretching vibrations of tetrahedral and octahedral lattice sites respectively. The XRD analysis shows the crystalline nature of nanoparticles and the average nano-crystallite size is found to be 18 nm − 26 nm. The crystallite size increases with increase in the concentration of iron. The morphology of the samples is analyzed using scanning electron microscope and is found to be spherical in shape. The optical properties are characterized using UV–Vis spectral analysis and PL study. UV–Visible absorption spectra show absorption peaks of iron doped nickel sulphide nanoparticles and the band exhibits a blue shift, indicates quantum size effect. Electrochemical studies revealed two oxidation peaks at a potential about −0.3 V and 0.7 V for pure nickel sulphide nanoparticles and in addition to it, a redox peak is observed at a potential about −0.5 V due to the doping of iron into the nickel sulphide nanoparticles. The synthesized nanoparticles may be used as high-performance electrode materials for supercapacitor applications.
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    SYNTHESIS AND FABRICATION OF NANOSTRUCTURED MOS2/PANI NANOCOMPOSITES BY MICROWAVE ASSISTED METHOD FOR ELECTROCHEMICAL APPLICATIONS
    (ScienceDirect, 2021) Krithika, S; Balavijayalakshmi, J
    Transition metal dichalcogenides (TMDCs) are two dimensional nanomaterials made up of a monolayer of transition metal atoms sandwiched (X-M-X) between two layers of chalcogen atoms in a hexagonal lattice. Molybdenum di sulfide (MoS2) have attracted much attention among the TMDCs family and is a suitable electrode material for supercapacitors. It has remarkable physical and chemical properties such as large surface area, sheet like structure, superior capability and lower rates of cyclic induced degradation. However, MoS2 suffers from lower electronic conductivity that limits its energy storage. Hence the conducting polymer, polyaniline is doped with the MoS2 to overcome the deficiencies and to enhance the electrochemical performance. A novel microwave assisted method is implemented to synthesize MoS2/PANI nanocomposites for the strategy of supercapacitors. The microwave assisted processing of MoS2/PANI nanocomposites provides several advantages than the conventional heating method such as tuning the physiochemical properties as reduction of impurity, mono dispersivity in the morphology that results in enhancing the electrochemical performance. The phase purity, homogeneity, and functional groups present in the MoS2/PANI nanocomposites are synthesized and characterized by X-ray diffraction (XRD), Field Emission Scanning Electron microscope (FESEM), High Resolution Transmission Electron Microscope (HR-TEM), Fourier Transform infrared spectroscopy (FT-IR), UV–Visible (UV–Vis) absorption spectroscopy and Raman spectroscopy. The optimized MoS2 /PANI nanosheets exhibits a high specific capacitance of 348 F/g at 0.5 A/g and MoS2/PANI nanocomposites retains 89.21% of its initial specific capacitance even after 2000 cycles. Hence the strategy of microwave assisted synthesis of MoS2/PANI nanocomposites improve the electrochemical performance of two dimensional MoS2 based electrode materials for energy storage.