Vinod Mathew | Mahatma Gandhi University, Kottayam (original) (raw)

Papers by Vinod Mathew

Research paper thumbnail of Electrical conductivity and dielectric behaviour of PPG 4 –AgCF 3 SO 3 :Al 2 O 3 nanocomposite gel polymer electrolyte system

Journal of Solid State Electrochemistry, 2011

In this report, the synthesis of solvent-free poly(propylene glycol) 4000 (PPG4)–silver triflate ... more In this report, the synthesis of solvent-free poly(propylene glycol) 4000 (PPG4)–silver triflate (AgCF3SO3):xAl2O3 nanocomposite gel polymer electrolytes containing four different amounts of Al2O3 nanoparticles corresponding to x = 1, 3, 5 and 7 wt.%, respectively, with an ether oxygen-to-metal cation ratio (O–M) of 4:1 together with their vibrational spectroscopic characteristics derived from Fourier transform infrared (FT-IR ) spectroscopic analysis at room temperature (25 °C) is described. Furthermore, a detailed investigation concerning their mechanism of ion transport performed by means of complex impedance analysis in the frequency range 20 Hz to 1 MHz and over the temperature region 25–90 °C and analysed in terms of electrical conductivity spectra, electrical modulus spectra and impedance spectra has indicated that the typical composition PPG4–AgCF3SO3:5 wt.% Al2O3 would exhibit the best room temperature electrical conductivity of 6.2 × 10−4 S cm−1 owing to the mobility of coordinated silver cations through the mechanism of enhanced segmental motion of the PPG4 polymer chains as aided by the various coordinating sites available within the polymer network. It is also demonstrated from the present FT-IR results that significant changes in the intensity, shape and position of the different vibrational bands corresponding to –OH stretching, C–O–C stretching, C–H stretching and C–O–C in C–H stretching modes occur as a result of the incorporation of Al2O3 nanofiller particles into the PPG4–AgCF3SO3 complex. It is evident from the conductivity data that the observed enhancement in electrical conductivity would result from appropriate changes in ionic association occurring in the form of probable ion–ion and ion–polymer interactions involving Al2O3 nanofiller additive in accordance with the Lewis acid–base model of polymer–salt–filler interactions.

Research paper thumbnail of An investigation on the performance of a silver ionic solid electrolyte system for a new detergent-based nanocrystalline dye-sensitized solar cell

Solar Energy Materials and Solar Cells, 2008

Research paper thumbnail of AC Conductivity, XRD and transport properties of melt quenched PbI 2 –Ag 2 O–Cr 2 O 3 system

Ionics, 2008

Composite materials used for electrode and electrolyte materials have been intensely studied in v... more Composite materials used for electrode and electrolyte materials have been intensely studied in view of their advantages such as higher conductivity and better operational performance compared to their single-phase counterparts. The present work aims at studying the electrical and structural characteristics of a new composite electrolyte namely, (PbI2)x − (Ag2O–Cr2O3)100−x where x = 5, 10, 15, 20, and 25 mol%, respectively, prepared by the melt quenching technique. The room temperature X-ray diffraction spectra revealed certain crystalline phases in the samples. AC conductivity analysis for all the prepared samples was carried out over the frequency range 1 MHz–20 Hz and in the temperature window 297–468 K. The room temperature conductivity values were calculated to be in the order of 10−5–10−3 Scm−1. An Arrhenius dependence of temperature with conductivity was observed, and the activation energies calculated were found to be in the range 0.27–0.31 eV. Furthermore, the total ionic transport number (t i) values obtained for all these indicated the ionic nature of this system.

Research paper thumbnail of Performance of a new polymer electrolyte incorporated with diphenylamine in nanocrystalline dye-sensitized solar cell

Solar Energy Materials and Solar Cells, 2008

Research paper thumbnail of The use of 2,6-bis ( N-pyrazolyl) pyridine as an efficient dopant in conjugation with poly(ethylene oxide) for nanocrystalline dye-sensitized solar cells

Electrochimica Acta, 2008

Poly (ethylene oxide)(PEO)/2, 6-bis (N-pyrazolyl) pyridine (BNPP) polymer electrolyte based photo... more Poly (ethylene oxide)(PEO)/2, 6-bis (N-pyrazolyl) pyridine (BNPP) polymer electrolyte based photoelectrochemical cells have been fabricated with [cis-dithiocyanato-N, N-bis (2, 2′ bipyridyl-4, 4′ dicarboxylic acid) ruthenium (II)] dihydrate (N3 dye) dye complex as the ...

Research paper thumbnail of Synthesis and Transport Characteristics of PbI2 - Ag2O - Cr2O3 Superionic System

The present work involves the preparation and characterization of a new superionic system namely,... more The present work involves the preparation and characterization of a new superionic system namely, (PbI2)x -(Ag2O-Cr2O3)100-x where x = 5, 10, 15, 20, and 25 mol% respectively. The varieties of samples were synthesized by the rapid melt quenching technique. Complex impedance analysis of all these samples was carried out over the frequency range 1 MHz - 20 Hz in the temperature window 300 - 463 K. The Fourier transform infrared (FTIR) spectra were recorded over the wave number region 4000 - 500 cm-1 by the KBr pellet method at room temperature. Furthermore, the ionic transport number (ti) values were obtained for all these specimens by Wagner's polarization technique. Impedance spectral analyses have indicated their room-temperature electrical conductivities to be of the order of 10-4 Scm-1.The detailed FTIR results obtained for most of the samples in this system have revealed the absorption bands around 850 cm-1 corresponding to CrO42- molecular species. The ion transport number values as determined by the Wagner's polarization method were found to be greater than 0.95 thus indicating the ionic nature of this system for device applications.

Research paper thumbnail of Influence of 2,6 (N-pyrazolyl)isonicotinic acid on the photovoltaic properties of a dye-sensitized solar cell fabricated using poly(vinylidene fluoride) blended with poly(ethylene oxide) polymer electrolyte

Electrochimica Acta, 2011

Research paper thumbnail of Electrical conductivity and dielectric behaviour of PPG 4 –AgCF 3 SO 3 :Al 2 O 3 nanocomposite gel polymer electrolyte system

Journal of Solid State Electrochemistry, 2011

In this report, the synthesis of solvent-free poly(propylene glycol) 4000 (PPG4)–silver triflate ... more In this report, the synthesis of solvent-free poly(propylene glycol) 4000 (PPG4)–silver triflate (AgCF3SO3):xAl2O3 nanocomposite gel polymer electrolytes containing four different amounts of Al2O3 nanoparticles corresponding to x = 1, 3, 5 and 7 wt.%, respectively, with an ether oxygen-to-metal cation ratio (O–M) of 4:1 together with their vibrational spectroscopic characteristics derived from Fourier transform infrared (FT-IR ) spectroscopic analysis at room temperature (25 °C) is described. Furthermore, a detailed investigation concerning their mechanism of ion transport performed by means of complex impedance analysis in the frequency range 20 Hz to 1 MHz and over the temperature region 25–90 °C and analysed in terms of electrical conductivity spectra, electrical modulus spectra and impedance spectra has indicated that the typical composition PPG4–AgCF3SO3:5 wt.% Al2O3 would exhibit the best room temperature electrical conductivity of 6.2 × 10−4 S cm−1 owing to the mobility of coordinated silver cations through the mechanism of enhanced segmental motion of the PPG4 polymer chains as aided by the various coordinating sites available within the polymer network. It is also demonstrated from the present FT-IR results that significant changes in the intensity, shape and position of the different vibrational bands corresponding to –OH stretching, C–O–C stretching, C–H stretching and C–O–C in C–H stretching modes occur as a result of the incorporation of Al2O3 nanofiller particles into the PPG4–AgCF3SO3 complex. It is evident from the conductivity data that the observed enhancement in electrical conductivity would result from appropriate changes in ionic association occurring in the form of probable ion–ion and ion–polymer interactions involving Al2O3 nanofiller additive in accordance with the Lewis acid–base model of polymer–salt–filler interactions.

Research paper thumbnail of An investigation on the performance of a silver ionic solid electrolyte system for a new detergent-based nanocrystalline dye-sensitized solar cell

Solar Energy Materials and Solar Cells, 2008

Research paper thumbnail of AC Conductivity, XRD and transport properties of melt quenched PbI 2 –Ag 2 O–Cr 2 O 3 system

Ionics, 2008

Composite materials used for electrode and electrolyte materials have been intensely studied in v... more Composite materials used for electrode and electrolyte materials have been intensely studied in view of their advantages such as higher conductivity and better operational performance compared to their single-phase counterparts. The present work aims at studying the electrical and structural characteristics of a new composite electrolyte namely, (PbI2)x − (Ag2O–Cr2O3)100−x where x = 5, 10, 15, 20, and 25 mol%, respectively, prepared by the melt quenching technique. The room temperature X-ray diffraction spectra revealed certain crystalline phases in the samples. AC conductivity analysis for all the prepared samples was carried out over the frequency range 1 MHz–20 Hz and in the temperature window 297–468 K. The room temperature conductivity values were calculated to be in the order of 10−5–10−3 Scm−1. An Arrhenius dependence of temperature with conductivity was observed, and the activation energies calculated were found to be in the range 0.27–0.31 eV. Furthermore, the total ionic transport number (t i) values obtained for all these indicated the ionic nature of this system.

Research paper thumbnail of Performance of a new polymer electrolyte incorporated with diphenylamine in nanocrystalline dye-sensitized solar cell

Solar Energy Materials and Solar Cells, 2008

Research paper thumbnail of The use of 2,6-bis ( N-pyrazolyl) pyridine as an efficient dopant in conjugation with poly(ethylene oxide) for nanocrystalline dye-sensitized solar cells

Electrochimica Acta, 2008

Poly (ethylene oxide)(PEO)/2, 6-bis (N-pyrazolyl) pyridine (BNPP) polymer electrolyte based photo... more Poly (ethylene oxide)(PEO)/2, 6-bis (N-pyrazolyl) pyridine (BNPP) polymer electrolyte based photoelectrochemical cells have been fabricated with [cis-dithiocyanato-N, N-bis (2, 2′ bipyridyl-4, 4′ dicarboxylic acid) ruthenium (II)] dihydrate (N3 dye) dye complex as the ...

Research paper thumbnail of Synthesis and Transport Characteristics of PbI2 - Ag2O - Cr2O3 Superionic System

The present work involves the preparation and characterization of a new superionic system namely,... more The present work involves the preparation and characterization of a new superionic system namely, (PbI2)x -(Ag2O-Cr2O3)100-x where x = 5, 10, 15, 20, and 25 mol% respectively. The varieties of samples were synthesized by the rapid melt quenching technique. Complex impedance analysis of all these samples was carried out over the frequency range 1 MHz - 20 Hz in the temperature window 300 - 463 K. The Fourier transform infrared (FTIR) spectra were recorded over the wave number region 4000 - 500 cm-1 by the KBr pellet method at room temperature. Furthermore, the ionic transport number (ti) values were obtained for all these specimens by Wagner's polarization technique. Impedance spectral analyses have indicated their room-temperature electrical conductivities to be of the order of 10-4 Scm-1.The detailed FTIR results obtained for most of the samples in this system have revealed the absorption bands around 850 cm-1 corresponding to CrO42- molecular species. The ion transport number values as determined by the Wagner's polarization method were found to be greater than 0.95 thus indicating the ionic nature of this system for device applications.

Research paper thumbnail of Influence of 2,6 (N-pyrazolyl)isonicotinic acid on the photovoltaic properties of a dye-sensitized solar cell fabricated using poly(vinylidene fluoride) blended with poly(ethylene oxide) polymer electrolyte

Electrochimica Acta, 2011