Srinivasan Nagarajan

Publications (22) View all

• Article: A PEDOT-reinforced exfoliated graphite composite as a Pt- and TCO-free flexible counter electrode for polymer electrolyte dye-sensitized solar cells.

  S. Nagarajan, P. Sudhagar, V. Raman, Woohyung Cho, K. S. Dhathathreyan, Yong Soo. Kang
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  ABSTRACT: Herein, we have demonstrated a highly efficient, flexible, and low-cost (Pt-free and TCO-free) counter electrode made of a highly conductive poly(3,4-ethylene dioxythiophene) (PEDOT)/exfoliated graphite composite in solid state dye-sensitized solar cells employing polymer electrolytes. Electropolymd. one-dimensional PEDOT nanofibers were firmly attached to a flexible exfoliated graphite sheet affording high catalytic activity and electron cond. PEDOT/exfoliated graphite counter electrode-based dye-sensitized solar cells showed an energy conversion efficiency of 5.7% with a solid polymer electrolyte, which is significantly higher than conventional Pt electrodes (4.4%) under similar device architecture conditions. [on SciFinder(R)]
  Journal of Materials Chemistry A: Materials for Energy and Sustainability. 01/2013; 1(4):1048-1054.
• Article: Efficient binary organic thiolate/disulfide redox mediators in dye-sensitized solar cells based on a carbon black counter electrode.

  Woohyung Cho, Donghoon Song, Yong-Gun Lee, Hwaseok Chae, Young Rae Kim, Yong Bum Pyun, S. Nagarajan, P. Sudhagar, Yong Soo. Kang
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  ABSTRACT: New thiolate/disulfide redox couples (M-/M2) were introduced and also combined with T-/T2, resulting in more efficient binary redox couples. The binary redox couples, in particular M-/T2, yielded a high energy conversion efficiency and reasonably stable performance with the carbon black counter electrode for dye-sensitized solar cells. [on SciFinder(R)]
  Journal of Materials Chemistry A: Materials for Energy and Sustainability. 01/2013; 1(2):233-236.
• Article: Evaluation of passive film behaviour of super austenitic stainless steels at different potential regions using dynamic electrochemical impedance spectroscopy

  S. Nagarajan, V. Raman, N. Rajendran
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  ABSTRACT: Potentiodynamic anodic polarisation and dynamic electrochemical impedance spectroscopic (DEIS) measurements were carried out on 316L stainless steel and alloys 926 and 31 in natural seawater in order to assess the crevice corrosion resistance. DEIS measurements were performed over a wide range of potentials covering the corrosion potential, passive region, breakdown region and dissolution region. The impedance measurements in potentiodynamic conditions clearly reveal the changes that occur in the passive layer with change in potential. The impedance spectra at different potential regions were also discussed elaborately. The surface morphology of the alloy after crevice corrosion was studied using optical microscope and atomic force microscopy. KeywordsStainless steel-Crevice corrosion-Dynamic electrochemical impedance spectroscopy-Atomic force microscopy
  Journal of Solid State Electrochemistry 04/2012; 14(7):1197-1204. · 2.13 Impact Factor
• Article: Sol–gel derived porous zirconium dioxide coated on 316L SS for orthopedic applications

  S. Nagarajan, N. Rajendran
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  ABSTRACT: The zirconia ceramics offers the required biocompatibility and corrosion resistance in the physiological medium, making it applicable for biomaterials. But, adequate utilization of porous zirconium dioxide (ZrO2) thin film has not been assessed. Hence, in the present work an attempt has been made to utilize the corrosion resistance and biocompatibility property of porous ZrO2. The ZrO2 were prepared using the sol–gel process and coated on 316LSS substrate via dip-coating technique. The phase composition, morphology and the elemental distribution of the coatings were investigated using X-ray diffraction analysis, atomic force microscopy, Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray analysis. The results revealed that the coated surface was porous, uniform and relatively well crystalline on the substrate. Invitro evaluation of the ZrO2 coated 316LSS samples were carried out in simulated body fluid and the corrosion resistance of the ZrO2 coated samples were examined using potentiodynamic cyclic polarisation and electrochemical impedance spectroscopy in simulated body fluid.
  Journal of Sol-Gel Science and Technology 04/2012; 52(2):188-196. · 1.63 Impact Factor
• Article: Effect of Si nanoparticles on the corrosion protection performance of organic coating on carbon steel in chloride environment.

  A. Madhankumar, S. Nagarajan, N. Rajendran, T. Nishimura
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  ABSTRACT: This work examines the effect of silicon (Si) nanoparticles on the corrosion protection performance of epoxy coating over carbon steel by Electrochem. Impedance Spectroscopy (EIS) and Transmission Electron Microscopy. The EIS was performed in a 0.1 M NaCl soln. after a wet/dry cyclic corrosion and continuous immersion test. The addn. of Si nanoparticles increased the film resistance (Rf) and the charge transfer resistance (Rct) of the coated steel. The surface anal. showed that uniform and fine Si-Fe complex oxides layers were formed acting as barrier layers that enhanced the corrosion protection of the coated steel in the wet/dry cyclic corrosion test. The results of the EIS of the coated steel with Si nanoparticles suggested that Si nanoparticles play a beneficial role in enhancing the corrosion resistance of org. coated steel. [on SciFinder(R)]
  Metals and Materials International 01/2012; 18(6):965-973. · 1.18 Impact Factor