Browsing by Author "R.B. Mathur"

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Carboxylated multiwalled carbon nanotubes based biosensor for aflatoxin detection
(2013) Chandan Singh; Saurabh Srivastava; Md. Azahar Ali; Tejendra K. Gupta; Gajjala Sumana; Anchal Srivastava; R.B. Mathur; Bansi D. Malhotra
We report results of studies relating to the development of an electrochemical immunosensor based on carboxylated multiwalled carbon nanotubes (c-MWCNTs) electrophoretically deposited onto indium tin oxide (ITO) glass. This c-MWCNTs/ITO electrode surface has been functionalized with monoclonal aflatoxin B1 antibodies (anti-AFB1) for the detection of aflatoxin-B1 using electrochemical technique. Electron microscopy, X-ray diffraction and Raman studies suggest successful synthesis of c-MWCNTs and the Fourier transform infra-red spectroscopic (FT-IR) studies reveal its carboxylic functionalized nature. The proposed immunosensor shows high sensitivity (95.2 μA ng-1 mL cm-2), improved detection limit (0.08 ng mL-1) in the linear detection range of 0.25-1.375 ng mL-1. The low value of association constant (0.0915 ng mL -1) indicates high affinity of immunoelectrode towards aflatoxin (AFB1). © 2013 Elsevier B.V.
Multifunctional, robust, light-weight, free-standing MWCNT/phenolic composite paper as anodes for lithium ion batteries and EMI shielding material
(Royal Society of Chemistry, 2014) Satish Teotia; Bhanu Pratap Singh; Indu Elizabeth; Vidya Nand Singh; Raman Ravikumar; Avanish Pratap Singh; S. Gopukumar; S.K. Dhawan; Anchal Srivastava; R.B. Mathur
Energy density of Li-ion batteries is marred due to the additional weight of copper, which is used as a current collector. In this work, fabrication of strong, graphitized, multiwalled carbon nanotubes (G-CNTs)/phenolic composite paper using a new dispersion technique is reported. The composite paper has been used as a free-standing current collector, as well as an anode material for Li-ion batteries, because of its good electrical conductivity of 76 S cm -1. This highly thin conductive composite paper (thickness 140 μm) also shows efficient electromagnetic interference (EMI) shielding effectiveness of 32.4 dB in Ku-band (12.4-18 GHz). Moreover, structural and morphological studies were carried out using TEM and SEM. The flexural strength of the composite paper was 30 MPa, which is good enough for use as an electrode in batteries. The electrochemical properties of the composite paper were investigated by galvanostatic charge-discharge test. It exhibits a stable reversible specific capacity for more than 45 cycles. EMI shielding effectiveness (SE) was measured using a vector network analyzer, and the total EMI-SE surpasses the value needed for commercial applications. © the Partner Organisations 2014.
Structural, transport and optical properties of (La0.6Pr0.4)0.65Ca0.35MnO3 nanocrystals: A wide band-gap magnetic semiconductor
(Royal Society of Chemistry, 2015) Satyam Kumar; G.D. Dwivedi; Shiv Kumar; R.B. Mathur; U. Saxena; A.K. Ghosh; Amish G. Joshi; H.D. Yang; Sandip Chatterjee
(La0.6Pr0.4)0.65Ca0.35MnO3 system has been synthesized via a sol-gel route at different sintering temperatures. Structural, transport and optical measurements have been carried out to investigate (La0.6Pr0.4)0.65Ca0.35MnO3 nanoparticles. Raman spectra show that Jahn-Teller distortion has been decreased due to the presence of Ca and Pr in A-site. Magnetic measurements provide a Curie temperature around 200 K and saturation magnetization (MS) of about 3.43μB/Mn at 5 K. X-ray photoemission spectroscopy study suggests that Mn exists in a dual oxidation state (Mn3+ and Mn4+). Resistivity measurements suggest that charge-ordered states of Mn3+ and Mn4+, which might be influenced by the presence of Pr, have enhanced insulating behavior in (La0.6Pr0.4)0.65Ca0.35MnO3. Band gap estimated from UV-Vis spectroscopy measurements comes in the range of wide band gap semiconductors (∼3.5 eV); this makes (La0.6Pr0.4)0.65Ca0.35MnO3 a potential candidate for device application. This journal is © The Royal Society of Chemistry 2015.