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Order fluctuation induced tunable light emission from carbon nano system
Mohanachandran Nair Sindhu Swapna, Sankararaman S, 2019, original scientific article

Abstract: The paper reports the thermal-induced order fuctuations, in a carbon nanosystem with carbon nanotubes (CNTs) synthesized by the incomplete combustion of gingelly oil. The sample annealed at diferent temperatures (30–400 °C) is subjected to various morphological and spectroscopic characterizations. The ultraviolet–visible spectroscopic and thermogravimetric analyses reveal the CNTs in the sample. The high-resolution transmission electron microscopy (HR-TEM) also confrms the formation of CNTs in the sample. The Raman spectrum and X-ray difraction pattern show the signature of multi-walled to single-walled CNT transformation and thus an order fuctuation on annealing. The quantum yield of the sample, measured by integrating sphere method, yields 46.15% at an emission wavelength of 575 nm. When the excitation wavelength is varied from 350 to 510 nm, the CIE coordinate moves from the white region to the yellowish-green region. The varying amount of CNTs in the soot, upon annealing is found to vary the luminescence emission from the sample. The study reveals the thermal-induced oscillatory order in carbon nanosystem with carbon nanotubes (CNTs) leading to tunable excitation/ thermal-dependent luminescence emission and thereby suggesting the possibility of converting the futile soot for fruitful applications in photonics and nanoelectronics.
Keywords: Carbon nanosystem, Single-walled carbon nanotubes, Multi-walled carbon nanotubes, Raman spectroscopy, Thermogravimetric analysis, CIE plot, Quantum yield, gingelly oil
Published in RUNG: 05.07.2022; Views: 1075; Downloads: 0
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Thermal induced order fluctuations in carbon nanosystem with carbon nanotubes
Mohanachandran Nair Sindhu Swapna, Sankararaman S, 2019, original scientific article

Abstract: The allotropes of carbon nanomaterials such as carbon nanotubes (CNTs) and nanoparticles (CNPs) have emerged as a thrust area of research during the last decade because of their unique properties.CNTs are widely used in microelectronic, sensor, bio-imaging, supercapacitors, fuel cell, and etc. applications. In the present work, we report the thermal induced order fluctuations in the CNPs with CNTs synthesized from camphor. The samples annealed to different temperatures are characterized by various spectroscopic techniques such as UV–Visible, Raman, Fourier Transform Infrared, and X-ray Photoelectron Spectroscopy. Samples’ structure and morphology are analyzed by scanning and transmission electron microscopes, and X-ray diffraction. The thermogravimetric analysis indicates not only the mass variation upon annealing but the thermal stability also. The spectroscopic and thermal analyses reveal the thermal induced oscillations in the carbon system which can be assigned to the dynamics in CNTs through desorption of hydrogen/ thinning or shortening of multi-walled CNTs/sp2 - sp3 conversions and the removal of amorphous carbon (AC). Since the amount of CNTs in the sample decides the electrical behavior, the sample can be tuned to a desired electrical conductivity by annealing and thus making it a tunable material for electronic applications.
Keywords: Carbon nanotubes, Camphor, Thermal induced oscillations
Published in RUNG: 05.07.2022; Views: 852; Downloads: 0
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Particulate Exhaust Analysis from Internal Combustion Engines
Mohanachandran Nair Sindhu Swapna, 2017, short scientific article

Abstract: Today the world is worried over the particulate emission from various forms of internal combustion engines. The present work is an attempt to understand the constituents of the particulate emission and its possible use. The particulate exhaust matter containing carbonaceous soot produced from the combustion of fuel containing hydrocarbons shows the presence of significant amount of carbon Nanomaterials. Hydrocarbons are the most widespread precursors among carbon sources employed in the production of carbon nanotubes (CNTs) and carbon nanoparticles (CNPs). Carbon nanotubes find application in fuel cells providing improved performance. The soot particles collected from the internal combustion diesel engines are cleaned, powdered and analyzed by various techniques. The CNPs are characterized by Field Emission Scanning Electron Microscopy (FESEM), X-Ray Powder Diffraction (XRD), Energy Dispersive X ray diffraction (EDS), Raman Spectroscopy, Photoluminescence spectroscopy (PL), Power spectrum and CIE plot. X Ray Diffraction and Raman spectroscopic analysis show the presence of carbon nanotubes in the amorphous materials.
Keywords: HydrocarbonsL Carbon nanotubes, Diesel engines, CIE plot, EDX, Raman spectroscopy
Published in RUNG: 30.06.2022; Views: 971; Downloads: 0
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Carbon Nanonecklaces with Carbon Nanotubes and Carbon Dots
Mohanachandran Nair Sindhu Swapna, Sankararaman S, 2017, original scientific article

Abstract: Carbon nanoparticles (CNP) have gained significant attention representing unique carbon-based nanomaterials that find applications in various fields of science and technology. Carbon nanotubes (CNTs) and carbon dots (CDs) have now been widely employed as an electrode in super capacitors, as fluorescent nanomaterials for imaging and for fuel cell applications. In the present work, we describe a simple, low cost and chemical free method of synthesizing stable CNPs aligned in the form of a chain popularly known as carbon necklace with CNTs and CDs. Carbon nanoparticles are synthesized by controlled combustion of camphor in a single step flame process. The CNPs synthesized are characterized using X-ray Powder diffraction (XRD), Raman Spectroscopy, Energy Dispersive X ray diffraction (EDX), Fourier Transform Infrared Spectroscopy (FTIR), UV-Visible absorption and Photoluminescent (PL) Spectroscopy. The morphology and size of the CNPs are examined using Field Emission Scanning Electron Microscope (FESEM) which shows ‘necklace’ structure. The CNPs are collected at two different heights and the particles formed are found in the range 30 to 60 nm. The UV- Visible and PL Spectra of the CNPs obtained show the presence CDs. The Raman Spectroscopic and XRD analysis indicate the presence of CNTs in the sample.
Keywords: Carbon nanoparticles, Combustion, Carbon nanotubes, Carbon dots, Carbon necklaces
Published in RUNG: 30.06.2022; Views: 1023; Downloads: 0
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Statistical mechanics of DNA-nanotube adsorption
Sh. A. Tonoyan, Davit Khechoyan, Yevgeni S. Mamasakhlisov, Artem Badasyan, 2020, original scientific article

Abstract: Attraction between the polycyclic aromatic surface elements of carbon nanotubes (CNTs) and the aromaticnucleotides of deoxyribonucleic acid (DNA) leads to reversible adsorption (physisorption) between the two, aphenomenon related to hybridization. We propose a Hamiltonian formulation for the zipper model that accountsfor the DNA-CNT interactions and allows for the processing of experimental data, which has awaited an availabletheory for a decade.
Keywords: Carbon nanotubes, desoxyribonucleic acid, physisorption
Published in RUNG: 30.06.2020; Views: 2464; Downloads: 0
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