Browsing by Author "Prabukumar, C."

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Beneficial Effect of Manganese(II) Ions on the Morphology of Polyol Synthesised Silver Nanowires
(Korean Institute of Metals and Materials, 2020) Prabukumar, C.; Bhat, K.U.
Abstract: Silver nanowires (Ag NWs) is a potential material to be used as the transparent conductive electrode (TCE) material, in the flexible electronic applications. The polyol method is the commonly used technique to synthesis the silver nanowires. The growth of the silver nanowires is facilitated by the oxidative etching of the silver seed particles. The present work investigates the influence of the manganese(II) ions to promote the growth of silver nanowires. The manganese(II) ions, due to its multiple oxidation states, play an essential role in removing the dissolved atomic oxygen, which prevent the growth of longer nanowires. Its effect on the length and diameter of the silver nanowires is studied in detail with different concentration levels. Characterization tools, such as X-ray diffractometry, electron microscopy (FESEM and TEM) and UV–VIS spectroscopy are used to characterise the synthesised silver nanowires. The addition of manganese(II) ions alters the aspect ratio of the silver nanowires that in turn, affects the optoelectrical properties of the TCE films. By using the synthesised silver nanowires, transparent heaters are successfully fabricated and their performances under different conditions are evaluated. Graphic Abstract: [Figure not available: see fulltext.]. © 2020, The Korean Institute of Metals and Materials.
Characterization of ZnO films produced by thermal evaporation and oxidation
(2015) Prabukumar, C.; Jayalakshmi, M.; Udaya, Bhat, K.
ZnO nanostructures such as nanowires and nanorods are beneficial in solar energy harvesting because they provide a structure with a large surface area. Also, they provide a direct pathway to electron transportation, eliminating the scope for grain boundary scattering. In this investigation, thin ZnO films were prepared by thermal evaporation of the Zn metal, which was followed by oxidation. Evaporation parameters and oxidation temperatures were fixed. The oxidation duration was the variable. The effect of oxidation time, on the morphology and structural properties were studied by using scanning electron microscopy and X-ray diffractometry. The study shows that with increase in oxidation time, the morphology changed to nanorods from initial flake morphology. As a function of oxidation time, the crystallinity and texture became more dominant. By using, I-V characteristic curves, it was found that the morphology changes alter the surface electrical conductivity of the prepared ZnO films. � (2015) Trans Tech Publications, Switzerland.
Characterization of ZnO films produced by thermal evaporation and oxidation
(Trans Tech Publications Ltd ttp@transtec.ch, 2015) Prabukumar, C.; Jayalakshmi, M.; Bhat, K.
ZnO nanostructures such as nanowires and nanorods are beneficial in solar energy harvesting because they provide a structure with a large surface area. Also, they provide a direct pathway to electron transportation, eliminating the scope for grain boundary scattering. In this investigation, thin ZnO films were prepared by thermal evaporation of the Zn metal, which was followed by oxidation. Evaporation parameters and oxidation temperatures were fixed. The oxidation duration was the variable. The effect of oxidation time, on the morphology and structural properties were studied by using scanning electron microscopy and X-ray diffractometry. The study shows that with increase in oxidation time, the morphology changed to nanorods from initial flake morphology. As a function of oxidation time, the crystallinity and texture became more dominant. By using, I-V characteristic curves, it was found that the morphology changes alter the surface electrical conductivity of the prepared ZnO films. Â© (2015) Trans Tech Publications, Switzerland.
Effect of solvent on the morphology of MoS2 nanosheets prepared by ultrasonication-assisted exfoliation
(2018) Prabukumar, C.; Sadiq, M.M.J.; Bhat, D.K.; Bhat, K.U.
The MoS2 nanosheets are prepared via liquid-phase exfoliation route. Bulk MoS2 powder is exfoliated by ultrasonication-assisted method with the aid of different solvents. The effect of solvents used on the morphology of the MoS2 nanosheets is investigated. The exfoliated material is analysed by using scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy and X-ray diffractometry. The MoS2 nanosheets exfoliated by using NMP-water mixture showed the better morphology than that exfoliated with the other solvent mixtures. � 2018 Author(s).
Effect of solvent on the morphology of MoS2 nanosheets prepared by ultrasonication-assisted exfoliation
(American Institute of Physics Inc. subs@aip.org, 2018) Prabukumar, C.; Mohamed, M.M.J.; Bhat, D.K.; Bhat, K.U.
The MoS2 nanosheets are prepared via liquid-phase exfoliation route. Bulk MoS2 powder is exfoliated by ultrasonication-assisted method with the aid of different solvents. The effect of solvents used on the morphology of the MoS2 nanosheets is investigated. The exfoliated material is analysed by using scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy and X-ray diffractometry. The MoS2 nanosheets exfoliated by using NMP-water mixture showed the better morphology than that exfoliated with the other solvent mixtures. Â© 2018 Author(s).
Effect of substrate temperature on the characteristics of ZnO films produced by a combination of thermal vapor deposition and oxidation processes
(Springer New York LLC barbara.b.bertram@gsk.com, 2017) Sneha, C.; Prabukumar, C.; Jayalakshmi, M.; Bhat, S.; Bhat, K.
In the present work, ZnO semiconductor films were prepared by following two step processes, namely, thermal vapor deposition of the zinc on the glass substrate followed by oxidative annealing. Substrate temperature during deposition of the zinc was varied. Structural properties and morphology of the ZnO films were investigated by using X-ray diffraction and scanning electron microscopy techniques. Hydrophobic nature of the film was confirmed by using contact angle analyser. Hall measurements facilitated the estimation of the carrier concentration, their mobility and their effect on the conductivity. Photoluminescence spectroscopy was used to analyse the lattice defect concentration in the film. Further, the sensor response of the ZnO film to CO gas was analysed. Sensor fabricated with ZnO films which were prepared by oxidizing Zn films deposited at higher substrate temperature were found to possess better response and faster response-recovery time than the film prepared using lower substrate temperature for zinc deposition. © 2017, Springer Science+Business Media, LLC.
Enhancing the electrochemical performance of ZnO anode by novel additive of MoS2–SnO2 nanocomposite for the zinc alkaline battery application
(Springer, 2022) Prabukumar, C.; Meti, S.; Bhat K, U.K.
ZnO nanorods and ZnO microrods are synthesized as the anode material for the Zn alkaline battery application. The present work studies the electrochemical performance of ZnO with regard to its size, morphology and MoS2–SnO2 nanocomposite as its additive towards the alkaline battery application. The properties, such as oxidation–reduction reaction, anti-corrosion behaviour, charge-transfer resistance and suppression of hydrogen evolution reaction (HER), are studied in detail. The structural characterization of ZnO samples is performed by using X-ray diffractometry. The morphological analysis of ZnO and MoS2–SnO2 nanocomposite is performed by using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), respectively. The atomic absorption spectroscopy (AAS) is employed to determine the solubility of ZnO samples in KOH solution. The electrochemical properties of the bare ZnO and the ZnO with MoS2–SnO2 additive (MoS2–SnO2/ZnO) samples are characterized by using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), cathodic polarization and Tafel polarization techniques. The ZnO with nanorod morphology shows better electrochemical performance than ZnO microrods and ZnO nanoparticles with sphere-like or plate-like morphology. The addition of MoS2–SnO2 nanocomposite with the ZnO improved the electrochemical activity, suppressed the HER activity and improved the anti-corrosion behaviour of the ZnO samples. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
Purification of Silver Nanowires Synthesised by Polyol Method
(2018) Prabukumar, C.; Bhat, K.U.
The mesh-based silver nanowires (Ag NWs) films are considered to be a good alternative to high-cost, brittle ITO as a transparent conductive electrode (TCE) for the sustainable flexible electronic devices. The polyol synthesis method is the common method to synthesis Ag NWs wherein Ag particles are also produced as a by-product. The present work used decantation combined with solvent-aid precipitation approach to remove silver particles from the Ag NWs suspension to produce quality Ag NWs based TCE. The synthesised and purified products were characterized by using Scanning electron microscopy, UV-Visible spectroscopy and X-ray diffractometry. This method proved to be a simpler and more effective one compared to filtration and centrifugation method as it yields more NWs against the particles. � 2018 Elsevier Ltd.
Purification of Silver Nanowires Synthesised by Polyol Method
(Elsevier Ltd, 2018) Prabukumar, C.; Bhat, K.U.
The mesh-based silver nanowires (Ag NWs) films are considered to be a good alternative to high-cost, brittle ITO as a transparent conductive electrode (TCE) for the sustainable flexible electronic devices. The polyol synthesis method is the common method to synthesis Ag NWs wherein Ag particles are also produced as a by-product. The present work used decantation combined with solvent-aid precipitation approach to remove silver particles from the Ag NWs suspension to produce quality Ag NWs based TCE. The synthesised and purified products were characterized by using Scanning electron microscopy, UV-Visible spectroscopy and X-ray diffractometry. This method proved to be a simpler and more effective one compared to filtration and centrifugation method as it yields more NWs against the particles. Â© 2018 Elsevier Ltd.
SnO2 nanoparticles functionalized MoS2 nanosheets as the electrode material for supercapacitor applications
(Institute of Physics Publishing helen.craven@iop.org, 2019) Prabukumar, C.; Mohamed, M.; Krishna Bhat, D.; Udaya Bhat, K.
Tin oxide (SnO2) nanoparticles undergo the volume expansion during an electrochemical cycle. This volume expansion leads to discontinuities in the form of microcracks in the electrode material. The problem of charge transportation associated with this microcracking limits the application of SnO2 in the energy storage application such as supercapacitors. The present work approached to solve this problem by incorporating the MoS2 nanosheets along with the SnO2 nanoparticles. The SnO2 nanoparticles are functionalized onto the surface of the MoS2 nanosheets by the ligand exchange process. The MoS2 nanosheets act as the support material for the SnO2 nanoparticles. The electrode material prepared using SnO2 nanoparticles and nanocomposite of SnO2 functionalized MoS2 nanosheets are tested by cyclic voltammetry and galvanostatic charge-discharge measurements. The specific capacity of the MoS2-SnO2 nanocomposite is calculated to be 61.6 F g-1 which is 4.4 fold higher than that of bare SnO2 nanoparticles. The improvement in the electrochemical performance of SnO2 is attributed to the high surface area and the charge transportation provided by the MoS2 nanosheets. © 2019 IOP Publishing Ltd.
Structural and morphological changes with substrate heating in zinc films synthesized by thermal vapor deposition technique
(Springer New York LLC barbara.b.bertram@gsk.com, 2017) Sneha, C.; Prabukumar, C.; Jayalakshmi, M.; Bhat, K.U.
Zinc oxide (ZnO) films are used in numerous applications such as solar cells, gas sensors, nanogenerators, etc., owing to their large band gap, piezoelectric activity and versatile nanostructures. Deposition of zinc films and their subsequent oxidation is considered as one of the successful methods to obtain nanostructured ZnO films. It has been reported that the structural features of the oxide film depends on the characteristics of parent zinc film; which in turn depends on the deposition parameters. In the present work, zinc films were synthesized by thermal vacuum deposition route. In order to understand the effect of substrate heating during deposition, zinc films were deposited on glass with different substrate temperatures, in the range of room temperature to 180 °C. The structural and morphological properties of as-synthesized films were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) techniques. The XRD data confirmed that the as-synthesized films have strong (002) preferential orientation. Notable changes were observed such as change in crystallite size, texture coefficient and strain in the films, upon changing the substrate temperature. The morphology of as-synthesized zinc films found to consist of hexagonal-plate like structures. It was observed that the dimensions of the hexagonal-plates were changed in accordance with the substrate temperature. DSC results indicated a depression in the melting point of zinc films compared to bulk zinc and it is attributed to the nanoscale features constituting the film. © 2017, Springer Science+Business Media New York.