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Nanocrystalline cerium oxide coated fiber optic gas sensor
B. Renganathan,D. Sastikumar,A. Chandra Bose,R. Srinivasan,A.R. Ganesan 한국물리학회 2014 Current Applied Physics Vol.14 No.3
A clad-modified fiber optic sensor with nanocrystalline CeO2 is proposed for gas detection. As-prepared and annealed CeO2 (500 C) samples have been used as gas sensing media. The spectral characteristics of the fiber optic gas sensor are studied for various concentrations of ammonia, ethanol and methanol gases (0e500 ppm). The sensor exhibits linear variation in the spectral peak intensity with the gas concentration. The characteristics of the sensor are also studied for gas selectivity. The time response characteristics of the sensor are reported.
Growth of nanolaminate structure of tetragonal zirconia by pulsed laser deposition
Balakrishnan, Govindasamy,Kuppusami, Parasuraman,Sastikumar, Dillibabu,Song, Jung Il Springer 2013 Nanoscale research letters Vol.8 No.1
<P>Alumina/zirconia (Al<SUB>2</SUB>O<SUB>3</SUB>/ZrO<SUB>2</SUB>) multilayer thin films were deposited on Si (100) substrates at an optimized oxygen partial pressure of 3 Pa at room temperature by pulsed laser deposition. The Al<SUB>2</SUB>O<SUB>3</SUB>/ZrO<SUB>2</SUB> multilayers of 10:10, 5:10, 5:5, and 4:4 nm with 40 bilayers were deposited alternately in order to stabilize a high-temperature phase of zirconia at room temperature. All these films were characterized by X-ray diffraction (XRD), cross-sectional transmission electron microscopy (XTEM), and atomic force microscopy. The XRD studies of all the multilayer films showed only a tetragonal structure of zirconia and amorphous alumina. The high-temperature XRD studies of a typical 5:5-nm film indicated the formation of tetragonal zirconia at room temperature and high thermal stability. It was found that the critical layer thickness of zirconia is ≤10 nm, below which tetragonal zirconia is formed at room temperature. The XTEM studies on the as-deposited (Al<SUB>2</SUB>O<SUB>3</SUB>/ZrO<SUB>2</SUB>) 5:10-nm multilayer film showed distinct formation of multilayers with sharp interface and consists of mainly tetragonal phase and amorphous alumina, whereas the annealed film (5:10 nm) showed the inter-diffusion of layers at the interface.</P>
Gas sensing property of lithium tetraborate clad modified fiber optic sensor
R. Mohandoss,S. Dhanuskodi,B. Renganathan,D. Sastikumar 한국물리학회 2013 Current Applied Physics Vol.13 No.6
The micro structured plate-like lithium tetraborate, Li2B4O7 (1 mm in diameter) has been prepared by sol egel method and characterized structurally by X-ray diffraction and morphologically by scanning electron microscopy. UVeVis spectrum shows about 60% transparency in the visible region and the optical energy band gap is found to be 3.5 eV which is also confirmed by strong near band edge emission from luminescence spectrum. The spectral characteristics of the cladding modified fiber optic sensor coated with microcrystalline Li2B4O7 are studied for various concentrations of ethanol, methanol and ammonia (50e500 ppm). At 298 K, the sensitivity for ethanol is 10 counts/ppm which is relatively higher than ammonia (4 counts/ppm) and methanol (3 counts/ppm). The time response of the sensor is presented for pure Li2B4O7 with ethanol gas.
M. Parthibavarman,B. Renganathan,D. Sastikumar 한국물리학회 2013 Current Applied Physics Vol.13 No.7
We have successfully synthesized Co doped SnO2 nanoparticles by a simple microwave irradiation technique. Powder X-ray diffraction results reveal that the SnO2 doped with cobalt concentration from 0 to 5 wt % crystallizes in tetragonal rutile-type structure. The products were annealed at 600 ℃ for 5 h in ambient atmosphere in order to improve crystallinity and structural perfection. Transmission electron microscopy (TEM) studies illustrate that both the undoped and Co doped SnO2 crystallites form in spherical shapes with an average diameter of 30e15 nm, which is in good agreement with the average crystallite sizes calculated by Scherrer’s formula. A considerable red shift in the absorbing band edge was observed with increasing of Co content (0-5 wt %) by using UVeVis diffuse reflectance spectroscopy (DRS). Oxygen-vacancies, tin interstitial and structural defects were analyzed using photoluminescence (PL) spectroscopy. Electron paramagnetic resonance (EPR) spectroscopic studies clearly showed that the Co2+ was incorporated into the SnO2 host lattice. Ethanol gas sensitivity of pure and Co-doped (5 wt %)SnO2 nanoparticles were experimented at ambient temperature using optical fiber based on cladmodified method. By modifying the clad exposure to ethanol vapor, the sensitivities were estimated to be 18 and 30 counts/100 ppm for undoped and Co-doped SnO2 nanoparticles, respectively. These results show that the Co doping into SnO2 enhances its ethanol gas sensitivity significantly.
Balakrishnan, G,Thirumurugesan, R,Mohandas, E,Sastikumar, D,Kuppusami, P,Songl, J I American Scientific Publishers 2014 Journal of nanoscience and nanotechnology Vol.14 No.10
<P>Aluminium oxide (Al2O3) thin films were deposited on Si (100) substrates at an optimized oxygen partial pressure of 3 x 10(-3) mbar at room temperature by pulsed laser deposition (PLD). The films were characterized by high temperature X-ray diffraction (HTXRD), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The HTXRD pattern showed the cubic y-Al2O3 phase in the temperature range 300-973 K. At temperatures 1073 K, the δ and θ-phases of Al2O3 were observed. The mean linear thermal expansion coefficient and volume thermal expansion coefficient of γ-Al2O3 was found to be 12.66 x 10(-6) K(-1) and 38.87 x 10(-6) K(-1) in the temperature range 300 K-1073 K. The field emission scanning electron microscopy revealed a smooth and structureless morphology of the films deposited on Si (100). The atomic force microscopy study indicated the increased crystallinity and surface roughness of the films after annealing at high temperature.</P>
Edakkaparamban Shuaib,Parasseri Muhammed Shafi,Yogesh Gaurav Kumar,Arumugam Chandra Bose,Dillibabu Sastikumar 한국탄소학회 2021 Carbon Letters Vol.31 No.4
In this work, a simple nonenzymatic glucose sensor has been proposed based on coconut shell charcoal (CSC) modifed nickel foil as working electrode in a three-electrode electrochemical cell. Charcoal was prepared by the pyrolysis of coconut shells. The most important advantages of coconut shells are cost-efectiveness and their abundance in nature. The morphology and phase of the CSC powder were characterized by scanning electron microscopy and X-ray difraction. The electrochemical performance of the CSC powder coated Nickel foil electrode was investigated by cyclic voltammetry and chronoamperometry. The sensor shows a higher sensitivity of 2.992 mA cm−2 mM−1 in the linear range of 0.5–5.5 mM and slightly lower sensitivity of 1.1526 mA cm−2 mM−1 in the range of 7–18.5 mM glucose concentration with a detection limit of 0.2 mM. The anti-interference property of CSC powder also was investigated and found that the response of interfering species was less signifcant compared to glucose response. The proposed sensor ofers good sensitivity, wide linear range, and a very low response to interfering biomolecules.