International Conference

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Author: search.filters.author.Meena PEnd date: 2020

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    GREEN SYNTHESIS OF SILVER NANOPARTICLES (AG NPS) USING GOMPHRENA GLOBOSA (GLOBE AMARANTH) LEAF EXTRACT, CHARACTERIZATION, AND ANTIBACTERIAL ACTIVITY
    (Amrita Vishwa Vidyapeetham, Coimbatore, 2019-12-15) Tamilarasi P; Meena P
    Among the various methods explored for the synthesis of silver nanoparticles (Ag NPs), the green synthesis method has received great attention as a cost effective and environmental friendly method as it avoids toxicity. In the present work, silver nanoparticles were synthesized using silver nitrate as the precursor and an aqueous extract of fresh leaves of Gomphrena globosa (Globe amaranth) as the reducing and stabilizing agent. The active phytochemicals present in the leaves cause quick reduction of silver ions (Ag+) to metallic silver nanoparticles (Ag0). The formation of Ag nanoparticles was initially confirmed by visual observation through the color change of the mixture. The silver nanoparticles obtained were characterized using UV-visible absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), Scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDAX), High-resolution transmission electron microscopy (HR-TEM), and Selected area electron diffraction (SAED) analysis. The synthesized silver nanoparticles show excellent antibacterial activity against three gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, Micrococcusluteus) and three gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae).
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    SYNTHESIS OF CO3O4 NANOPARTICLES FOR SENSING TOXIC GAS AT ROOM TEMPERATURE
    (Amrita Vishwa Vidyapeetham, Coimbatore, 2019-12-15) Jincy C.S; Meena P
    Over the past few decades, there has been an increasing demand for inexpensive, accurate, portable and reliable gas sensors which can be used to detect combustible, flammable and toxic gases, and oxygen depletion. Typically, gases of interest include CO, NO, NO2, NH3, SO2, CO2, CH4 and other hydrocarbons. These gases can be harmful to human health if present beyond a certain concentration. Among various metal oxide semiconductors, p-type Cobalt oxide semiconductors are excellent materials for fabricating highly sensitive and selective gas sensors of high-performance. In this study, a novel and low cost chemical route has been developed to synthesize Co3O4 nanostructures. The efficiency of Co3O4 nanomaterials is improved by means of introducing n-type dopants. The synthesized nanomaterials were characterized by different characterization techniques like UV, XRD, FTIR, SEM and EDAX analysis. The Cobalt oxide nanoparticles are observed to have a good response and sensitivity to ammonia gas at room temperature.
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    CU2FESNS4 (CFTS) NANOPARTICLES: POTENTIAL PHOTOVOLTAIC ABSORPTION MATERIALS FOR SOLAR CELL APPLICATION
    (National Institute of Technology, Tiruchirapalli, 2019-09-09) Deepika R; Meena P
    Nanoparticles of the environmentally benign Cu-based quaternary chalcogenide compound Cu2FeSnS4 (CFTS) were successfully synthesized and the powder coated as a thin film on a FTO substrate by spin coating. The CFTS nanoparticles were prepared by a simple, low cost hydrothermal reaction method. The prepared samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, UV-Vis spectroscopy and Field emission scanning electron microscopy with energy dispersive spectroscopy (FESEM – EDX). The results of the analyses confirm that the obtained nanoparticles are high crystalline with pure tetragonal structure. Morphological images show that the CFTS nanoparticles are closely packed with slight agglomeration. UV-Vis absorption spectrum revealed that the nanoparticles have a strong absorption band in the visible region with a band gap of 1.32 eV, which indicates their potential as promising materials for photovoltaic application. In the present study, the fabrication of CFTS based solar cells of layer configuration FTO/ZnO/CdS/CFTS has been reported. The fabricated solar cell was characterized by current- voltage (I-V) measurements under simulated AM 1.5 illumination.
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    PREPARATION AND PROPERTIES OF QUATERNARY SEMICONDUCTOR CU2NISNS4 (CNTS)) NANOPARTICLES FOR POTENTIAL SOLAR ABSORBER MATERIALS
    (SRM Institute of Science and Technology, 2019-01-28) Deepika R; Meena P
    Phase pure Cu2ZnSnS4 (CZTS) and its related quaternary chalcogenides are promising material for photovoltaic applications. The incorporation of transition metal cations into any semiconductor systems may led to very interesting physical and chemical properties which make them suitable for applications in optoelectronic devices. In this study, a novel synthesis of Cu2NiSnS4 (CNTS) quaternary nanoparticles by the facile Chemical Route Method. The structural, morphological, optical and electrical characteristics of the synthesized nanoparticles have been analyzed. The results obtained confirm the formation of phase pure CNTS nanoparticles. The average size of the synthesized nanoparticles is estimated to be around 30nm. The obtained optical band gap of the CNTS nanoparticles are in good agreement with the optimum value required for an absorber material in photovoltaic solar energy-conversions. This study shows the viability of synthesizing nanoparticles with elements which are abundantly available by using an environmentally-friendly and low cost process which is potential for energy- conversion applications.
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    COLLOIDAL CHEMICAL SYNTHESIS OF TERNARY SEMICONDUCTOR CU2SNS4 (CTS) NANOPARTICLES FOR POTENTIAL SOLAR ENERGY ABSORBER MATERIALS
    (Institute of science and technology, Jawaharlal Nehru Technology University, Hyderabad, 2018-10-04) Deepika R; Jincy C.S; Meena P
    Ternary semiconductor Cu2SnS4 (CTS) nanoparticles have been synthesized by the facileChemical Route Method. Structural, morphological and optical characterization studies of the synthesized CTS nanoparticles have been performed by X-ray diffraction (XRD), Raman Spectroscopy, Energy Dispersive Spectroscopy (EDS), Scanning Electron Microscope (SEM)and UV-VIS Spectroscopy (UV). XRD and Raman spectroscopy are used to confirm the structure and phase. Based on the EDS result, the stoichiometry of the Cu2SnS4 (CTS) was determined and the elemental distribution studied by mapping analysis. The optical absorption studies revealed that the CTS nanoparticles have direct optimal band gap in the range from 1.29 to 1.5eV, which indicates that these nanoparticles are potential absorber materials for thin film photovoltaic applications. The synthesized CTS nanoparticles can be transformed to the ink form, which can be used to directly coat large area thin film solar cells.
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    STUDIES ON SYNTHESIS AND CHARACTERIZATION OF CUSNANOPARTICLES
    (PSGR Krishnammal College for Women, Coimbatore, 2018-01-03) Deepika R; Meena P; Mythili A.R
    Copper sulfide nanoparticles which are promising materials with potential applications in solar energy conversion, catalysis, sensing etc., have attracted the interest of researchers in view of their non-toxic nature. In the present study, CuS nanoparticles have been synthesized by the facile Chemical Route method which has received much attention due to the simple operation, low cost, faster reaction rate, high yield, environmental safety, and low energy consumption. The synthesized nanoparticles have been characterized by X-Ray diffraction (XRD), Scanning electron microscopy (SEM) with energy-dispersive X-ray analysis (EDAX) and UV-VIS spectrophotometry.
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    PREPARATION AND CHARACTERIZATION OF ENVIRONMENTALLY SAFE TIN SULFIDE(SNS) NANOPARTICLES
    (PSGR Krishnammal College for Women, Coimbatore, 2018-01-03) Deepika R; Meena P; JosephineVincy P
    Nanoparticles of tinsulfide (SnS), are environmentally safe materials which are important as they are employed in optoelectronic devices.The band gap of SnS which is a binary semiconductor compound is about 1.3 eV, which is close to the optimum value required for the efficient sunlight absorption. SnS layers are used to enhance the efficiency of solar cells. In the present study,SnS nanoparticles have been synthesised by chemical route method. Structural, morphological and optical properties have been investigated with the help of X-ray diffraction technique (XRD), scanning electron microscope (SEM) with energy dispersive X-ray analysis (EDAX) and ultra-violet visible (UV) analysis.
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    STUDY OF PHOTO-CATALYTIC DEGRADATION OF ORGANIC DYES BY TIO2 NANOPARTICLES
    (PSGR Krishnammal College for Women, Coimbatore, 2018-01-03) Anshy Tom Dhanya A; Meena P; Mangalaraj D; Rajendra Kumar R.T
    Titanium oxide nanoparticles with size below 50 nm were synthesized by hydrothermal method with different pH values of the reaction solution. The nanoparticles were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Photoluminescence (PL) and Ultraviolet spectroscopy (UV) after calcination at 500°C for 2h. The synthesized TiO2 nanoparticles were related to the anatase phase and their crystalline structure was characterized by XRD. Bunched, Spherical and uniformly shaped TiO2 nanoparticles were observed in the SEM images. The photocatalytic behaviour of the synthesized TiO2 nanoparticles was examined by the photoluminescence method. As photocatalytic degradation is one of the most efficient processes for the degradation of dyes, the effect of these nanoparticles on the photocatalytic degradation of various dyes with different chromophores such as, triphenyl methane (Methyl violet), heteropolyaromatic dyes (Methylene blue, Rhodamine B) and azoic dyes( Methyl orange) was studied under Ultra violet light irradiation. The photo oxidation reactions were observed under UV lamp at a wavelength of 250 nm. The values of efficiency of degradation of the dyes were calculated and the values of the percentage of photocatalytic degradation for different pH values of the reaction solution were compared. The rate of degradation is found to increase on increasing the pH value. This photocatalytic degradation of dyes using nanoparticles is a low cost, eco-friendly and cost effective process in the removal of toxic dyes.
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    SYNTHESIS AND CHARACTERIZATION OF CUO - SNO2 COMPOSITE THIN FILMS BY SPRAY PYROLYSIS METHOD
    (PSGR Krishnammal College for Women, Coimbatore, 2018-01-03) Selleswari D; Meena P; Mangalaraj D
    Copper acetate and Tin dihydrate were used as a precursor to prepare CuO-SnO2 thin films. Composite films of different ratios were prepared by spray pyrolysis method. The prepared films were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray analysis (EDX) and Optical absorption spectroscopy. The grain size was calculated from different peaks is 27 to 54 nm shows nano structured thin films. EDX analysis confirms the composition of deposited thin film. The band gap of the composite thin films obtained from the optical absorption spectra is to be in the range of 2.98 to 3.67 eV
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    EFFECT OF SURFACTANT ON STRUCTURAL, MORPHOLOGICAL, OPTICAL AND ELECTRICAL PROPERTIES OF CUO NANOPARTICLES FOR APPLICATION IN P-N JUNCTION DIODE
    (Bannari Amman Institute of Technology, Sathyamangalam, 2017-08-17) Selleswari D; Meena P; Mangalaraj D; Jeevitha G
    Copper oxide nanomaterials have kindled the interest of researchers in view of their potential applications in electronic devices. In the present work, Copper oxide (CuO) nanoparticles were prepared through the simple hydrothermal method using two different concentrations (0.1 and 0.5 M) of the surfactant (CTAB) and their structural, optical, electrical and diode properties have been analyzed. From the XRD analysis, it was observed that the surfactant reduced the crystallite size of the CuO nanoparticles. It also caused an increase in the optical band gap and absorbance. The SEM analysis showed the strong influence of the surfactant on the structure of the nanoparticles. The presence of Cu and O elements was confirmed from the FT-IR spectrum. The study of the electrical properties revealed that the conductivity increased on using CTAB. The electrical parameters such as ideality factor (n), barrier height (ФB) and series resistance (Rs), and interface properties for the p-Si/CuO/Ag diodes have been analyzed by the I-V method.