Dr. PP George - Academia.edu (original) (raw)
Papers by Dr. PP George
Macromolecular Symposia, 2021
INTERNATIONAL CONFERENCE ON MULTIFUNCTIONAL MATERIALS (ICMM-2019), 2020
The electrical properties and transport mechanisms ofNi/PVA/n-Si MIS type SBDs was investigated u... more The electrical properties and transport mechanisms ofNi/PVA/n-Si MIS type SBDs was investigated using I-V measurements which were performed at room temperature. The fabricated MIS SBD exhibited good rectification ratio with low leakage current when compared to Ni/n-Si MS SBD. The evaluated SBH of MIS type SBDs using PVA as an interfacial layer was found to be 0.80 eV (I-V), 0.88 eV (Cheung), 0.81 eV (Norde) improved when compared to MS structure with 0.70 eV (I-V), 0.74eV (Cheung) and 0.72eV (Norde). The ideality factor (n) values were calculated using thermionic emission (TE) theory and were found to be 1.09 for the MS and 1.35 for the MIS SBDs. The R S , 'n' values were extracted for the MIS and MS SBDs using Cheung functions and were calculated as 171 Ω, 1.24 and 3345 Ω, 1.43 respectively. The series resistance (R S) values were also extracted from H(I) versus I plot and were found to be 459 Ω for MIS SBD and 15,669 Ω for the MS SBD. Furthermore, the surface potential versus forward voltage plot of the MIS SBDs yielded a SBH of 0.77 eV which is higher than 0.68 eV achieved for MS SBD. It can be concluded that the deliberately deposited PVA as an insulating layer at the Ni/n-Si interface remarkably varied the electrical properties of the fabricated Ni/PVA/n-Si MIS SBDs.
Journal of Bionanoscience, 2018
Advanced Science Letters, 2018
The green technology clubbed with the microwave irradiation allows one to produce the products an... more The green technology clubbed with the microwave irradiation allows one to produce the products and to reduce the number of production stages without increasing the cost. In this article, magnesium phosphate nanoparticles were successfully synthesized via a simple green chemical route using plant extract of Ocimum sanctum L. in microwave assisted method and followed by annealing at the temperature of 700 °C. The crystal structure, morphologies, elemental composition and optical properties of synthesized magnesium phosphate nanoparticles were systematically characterized by powdered X-ray diffraction (PXRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), Fourier Transform Infrared spectroscopy (FTIR) and UV-Vis Spectroscopic analysis. The structure of the magnesium phosphate was found to be monoclinic with the particle size of 43 nm. We conclude that the synthesis of magnesium phosphate nanoparticles using Ocimum sanctum L as reducing and stabilizing agent...
Coordination Chemistry Reviews, 2003
The synthesis and coordination chemistry of bis-and tris(phosphines) with PÃ/Si Ã/P, PÃ/O Ã/Si Ã/... more The synthesis and coordination chemistry of bis-and tris(phosphines) with PÃ/Si Ã/P, PÃ/O Ã/Si Ã/O Ã/P and P Ã/C Ã/Si Ã/CÃ/P linkages is reviewed. The catalytic reactions involving organometallic complexes of silylphosphines are presented. The silylbis-and tris(phosphines) show remarkable versatility in their coordination behavior with transition metals. The improved solubility of these ligands and their complexes facilitated spectroscopic studies to compliment the structural information obtained via single crystal X-ray diffraction studies. The syntheses and reactivity of other related acyclic and cyclic systems with P Ã/N Ã/SiÃ/N Ã/P and Paryl Ã/Si-aryl Ã/P linkages are also briefly described.
Journal of Bionanoscience, 2017
International Journal of Nanoscience, 2017
We present an easy synthetic method for the fabrication of encapsulated nanosized semiconductor C... more We present an easy synthetic method for the fabrication of encapsulated nanosized semiconductor CdE [E [Formula: see text] S, Se and Te] within the core of carbon capsule. We also discuss the growth of CdSC and neat CdS nanocrystals on stainless steel coupons (SSC) by a reaction under autogenic pressure at elevated temperature (RAPET) technique. The thermal decomposition of mixture of Cd(acetate)2 and sulfur, selenium and tellurium was carried out at 750[Formula: see text]C under air for 3[Formula: see text]h. The synthesized products were systematically characterized by X-ray powder diffraction, scanning electron microscopy (SEM) and transmission electron microscopy. Carbon matrix, with an average diameter of 250[Formula: see text]nm, encapsulated several nanometric-sized CdS nanocrystals, as evidenced from high resolution SEM (HRSEM). We examined the optical properties of this core/shell CdS@C and nonencapsulated CdS nanocrystals and found that both core shell and neat CdS nanocry...
International Journal of Nanoscience, 2017
The reaction under autogenic pressure at elevated temperature (RAPET) technique is proposed for s... more The reaction under autogenic pressure at elevated temperature (RAPET) technique is proposed for synthesizing a series of metal phosphide nanoparticles such as MoP, MoP2, Cu3P and CuP2 at 850[Formula: see text]C for 3.50[Formula: see text]h by reacting selectively the transition metal powders with elemental phosphorus. The obtained products are characterized by powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). A reaction mechanism is suggested based on the experimental results.
Applied Nanoscience, 2015
The novel flower-like WE 2 (E = S or Se) nanoflakes are synthesized and the growth of WS 2 and WS... more The novel flower-like WE 2 (E = S or Se) nanoflakes are synthesized and the growth of WS 2 and WSe 2 nanowires on stain less steel coupons (SSC) is observed by reaction under autogenic pressure at elevated temperature technique between the metallic tungsten and chalcogen powders at 750°C for 3 h. Powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy are used to characterize all reaction products, viz., neat WS 2 , WSe 2 powder, WS 2 /SSC and WSe 2 /SSC (stainless steel coupon). The photoluminescence spectrum of WS 2 and WSe 2 samples are also reported. In addition, the direct use of metals as precursors will devoid the harmful effects of organometallic precursor.
RSC Advances, 2011
Nanocrystalline (< 20 nm) gallium oxide coating on in situ formed amorphous carbon spheres... more Nanocrystalline (< 20 nm) gallium oxide coating on in situ formed amorphous carbon spheres is achieved by the controlled chemical reaction of gallium triacetylacetonate under autogenic pressure at elevated temperature (700 C) in an inert atmosphere. The as-...
RSC Advances, 2012
ABSTRACT Nickel sulfide and nickel selenide nanoparticles encapsulated in carbon shells are synth... more ABSTRACT Nickel sulfide and nickel selenide nanoparticles encapsulated in carbon shells are synthesized by the thermal decomposition of mixtures of nickel acetate and sulfur or selenium via a RAPET (Reaction under Autogenic Pressure at Elevated Temperatures) technique at 750 °C for 3 h. The synthesized products are systematically characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and the encapsulation of Ni3S2 and NiSe nanoparticles by a carbon shell is confirmed by transmission electron micrographs (TEM). Such materials have pausible applications in photo voltaic devices, magnetic devices, in catalysis and as electrodes for batteries. Coated carbon on the surface of Ni3S2 and NiSe nanocrystals acts as a protective layer, making them thermally as well as chemically stable. Additionally, the possibility of coating a pristine stainless steel plate with Ni3S2–C core-shell composite layers is also demonstrated.
The Journal of Physical Chemistry B, 2006
The thermal decomposition of commercial silicone grease was carried out in a closed reactor (Swag... more The thermal decomposition of commercial silicone grease was carried out in a closed reactor (Swagelok) that was heated at 800°C for 3 h, yielding a SiO 2-carbon composite with a BET surface area of 369 m 2 /g. The bulk conductivity (5.72 × 10-6 S‚cm-2) of the SiO 2-carbon composite was determined by impedance measurements. The as-prepared SiO 2-carbon composite was further annealed at 500°C in air for 2 h, which led to the formation of white paramagnetic silica particles (confirmed by ESR), possessing a surface area of 111 m 2 /g. The present synthetic technique requires unsophisticated equipment and a low-cost commercial precursor, and the reaction is carried out without a solvent, surfactant, or catalyst. The mechanism for the formation of a porous SiO 2-carbon composite from the silicone grease is also presented.
Phosphorus, Sulfur, and Silicon and the Related Elements, 2006
The reaction of N,N-bis(diphenylphosphino)piperzine with elemental sulfur or selenium in toluene ... more The reaction of N,N-bis(diphenylphosphino)piperzine with elemental sulfur or selenium in toluene under refluxing conditions afforded Ph 2 P(S)N(C 4 H 8)NP(S)Ph 2 or Ph 2 P(Se)N(C 4 H 8)NP(Se)Ph 2 in a quantitative yield. The molecular structures were determined by X-ray studies.
Nanoscale Research Letters, 2006
The reaction of pentaethoxy niobate, Nb(OEt)5, at elevated temperature (800 °C) under autogenic p... more The reaction of pentaethoxy niobate, Nb(OEt)5, at elevated temperature (800 °C) under autogenic pressure provides a chemical route to niobium oxide nanorods coated with amorphous carbon. This synthetic approach yielded nanocrystalline particles of Nb2O5@C. As prepared Nb2O5@C core-shell nanorods is annealed under air at 500 °C for 3 h (removing the carbon coating) results in neat Nb2O5nanorods. According to the TEM measurements, the Nb2O5crystals exhibit particle sizes between 25 nm and 100 nm, and the Nb2O5crystals display rod-like shapes without any indication of an amorphous character. The optical band gap of the Nb2O5nanorods was determined by diffuse reflectance spectroscopy (DRS) and was found to be 3.8 eV.
Journal of Nanoparticle Research, 2007
Abstract The thermal decomposition of a reaction mixture containing W (CO) 6 and PPh 3 yielded ca... more Abstract The thermal decomposition of a reaction mixture containing W (CO) 6 and PPh 3 yielded carbon encapsulated nanocrystals of tungsten monophosphide (WP). This reaction was carried out using the RAPET technique (reaction under autogenic pressure at ...
Macromolecular Symposia, 2021
INTERNATIONAL CONFERENCE ON MULTIFUNCTIONAL MATERIALS (ICMM-2019), 2020
The electrical properties and transport mechanisms ofNi/PVA/n-Si MIS type SBDs was investigated u... more The electrical properties and transport mechanisms ofNi/PVA/n-Si MIS type SBDs was investigated using I-V measurements which were performed at room temperature. The fabricated MIS SBD exhibited good rectification ratio with low leakage current when compared to Ni/n-Si MS SBD. The evaluated SBH of MIS type SBDs using PVA as an interfacial layer was found to be 0.80 eV (I-V), 0.88 eV (Cheung), 0.81 eV (Norde) improved when compared to MS structure with 0.70 eV (I-V), 0.74eV (Cheung) and 0.72eV (Norde). The ideality factor (n) values were calculated using thermionic emission (TE) theory and were found to be 1.09 for the MS and 1.35 for the MIS SBDs. The R S , 'n' values were extracted for the MIS and MS SBDs using Cheung functions and were calculated as 171 Ω, 1.24 and 3345 Ω, 1.43 respectively. The series resistance (R S) values were also extracted from H(I) versus I plot and were found to be 459 Ω for MIS SBD and 15,669 Ω for the MS SBD. Furthermore, the surface potential versus forward voltage plot of the MIS SBDs yielded a SBH of 0.77 eV which is higher than 0.68 eV achieved for MS SBD. It can be concluded that the deliberately deposited PVA as an insulating layer at the Ni/n-Si interface remarkably varied the electrical properties of the fabricated Ni/PVA/n-Si MIS SBDs.
Journal of Bionanoscience, 2018
Advanced Science Letters, 2018
The green technology clubbed with the microwave irradiation allows one to produce the products an... more The green technology clubbed with the microwave irradiation allows one to produce the products and to reduce the number of production stages without increasing the cost. In this article, magnesium phosphate nanoparticles were successfully synthesized via a simple green chemical route using plant extract of Ocimum sanctum L. in microwave assisted method and followed by annealing at the temperature of 700 °C. The crystal structure, morphologies, elemental composition and optical properties of synthesized magnesium phosphate nanoparticles were systematically characterized by powdered X-ray diffraction (PXRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), Fourier Transform Infrared spectroscopy (FTIR) and UV-Vis Spectroscopic analysis. The structure of the magnesium phosphate was found to be monoclinic with the particle size of 43 nm. We conclude that the synthesis of magnesium phosphate nanoparticles using Ocimum sanctum L as reducing and stabilizing agent...
Coordination Chemistry Reviews, 2003
The synthesis and coordination chemistry of bis-and tris(phosphines) with PÃ/Si Ã/P, PÃ/O Ã/Si Ã/... more The synthesis and coordination chemistry of bis-and tris(phosphines) with PÃ/Si Ã/P, PÃ/O Ã/Si Ã/O Ã/P and P Ã/C Ã/Si Ã/CÃ/P linkages is reviewed. The catalytic reactions involving organometallic complexes of silylphosphines are presented. The silylbis-and tris(phosphines) show remarkable versatility in their coordination behavior with transition metals. The improved solubility of these ligands and their complexes facilitated spectroscopic studies to compliment the structural information obtained via single crystal X-ray diffraction studies. The syntheses and reactivity of other related acyclic and cyclic systems with P Ã/N Ã/SiÃ/N Ã/P and Paryl Ã/Si-aryl Ã/P linkages are also briefly described.
Journal of Bionanoscience, 2017
International Journal of Nanoscience, 2017
We present an easy synthetic method for the fabrication of encapsulated nanosized semiconductor C... more We present an easy synthetic method for the fabrication of encapsulated nanosized semiconductor CdE [E [Formula: see text] S, Se and Te] within the core of carbon capsule. We also discuss the growth of CdSC and neat CdS nanocrystals on stainless steel coupons (SSC) by a reaction under autogenic pressure at elevated temperature (RAPET) technique. The thermal decomposition of mixture of Cd(acetate)2 and sulfur, selenium and tellurium was carried out at 750[Formula: see text]C under air for 3[Formula: see text]h. The synthesized products were systematically characterized by X-ray powder diffraction, scanning electron microscopy (SEM) and transmission electron microscopy. Carbon matrix, with an average diameter of 250[Formula: see text]nm, encapsulated several nanometric-sized CdS nanocrystals, as evidenced from high resolution SEM (HRSEM). We examined the optical properties of this core/shell CdS@C and nonencapsulated CdS nanocrystals and found that both core shell and neat CdS nanocry...
International Journal of Nanoscience, 2017
The reaction under autogenic pressure at elevated temperature (RAPET) technique is proposed for s... more The reaction under autogenic pressure at elevated temperature (RAPET) technique is proposed for synthesizing a series of metal phosphide nanoparticles such as MoP, MoP2, Cu3P and CuP2 at 850[Formula: see text]C for 3.50[Formula: see text]h by reacting selectively the transition metal powders with elemental phosphorus. The obtained products are characterized by powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). A reaction mechanism is suggested based on the experimental results.
Applied Nanoscience, 2015
The novel flower-like WE 2 (E = S or Se) nanoflakes are synthesized and the growth of WS 2 and WS... more The novel flower-like WE 2 (E = S or Se) nanoflakes are synthesized and the growth of WS 2 and WSe 2 nanowires on stain less steel coupons (SSC) is observed by reaction under autogenic pressure at elevated temperature technique between the metallic tungsten and chalcogen powders at 750°C for 3 h. Powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy are used to characterize all reaction products, viz., neat WS 2 , WSe 2 powder, WS 2 /SSC and WSe 2 /SSC (stainless steel coupon). The photoluminescence spectrum of WS 2 and WSe 2 samples are also reported. In addition, the direct use of metals as precursors will devoid the harmful effects of organometallic precursor.
RSC Advances, 2011
Nanocrystalline (< 20 nm) gallium oxide coating on in situ formed amorphous carbon spheres... more Nanocrystalline (< 20 nm) gallium oxide coating on in situ formed amorphous carbon spheres is achieved by the controlled chemical reaction of gallium triacetylacetonate under autogenic pressure at elevated temperature (700 C) in an inert atmosphere. The as-...
RSC Advances, 2012
ABSTRACT Nickel sulfide and nickel selenide nanoparticles encapsulated in carbon shells are synth... more ABSTRACT Nickel sulfide and nickel selenide nanoparticles encapsulated in carbon shells are synthesized by the thermal decomposition of mixtures of nickel acetate and sulfur or selenium via a RAPET (Reaction under Autogenic Pressure at Elevated Temperatures) technique at 750 °C for 3 h. The synthesized products are systematically characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and the encapsulation of Ni3S2 and NiSe nanoparticles by a carbon shell is confirmed by transmission electron micrographs (TEM). Such materials have pausible applications in photo voltaic devices, magnetic devices, in catalysis and as electrodes for batteries. Coated carbon on the surface of Ni3S2 and NiSe nanocrystals acts as a protective layer, making them thermally as well as chemically stable. Additionally, the possibility of coating a pristine stainless steel plate with Ni3S2–C core-shell composite layers is also demonstrated.
The Journal of Physical Chemistry B, 2006
The thermal decomposition of commercial silicone grease was carried out in a closed reactor (Swag... more The thermal decomposition of commercial silicone grease was carried out in a closed reactor (Swagelok) that was heated at 800°C for 3 h, yielding a SiO 2-carbon composite with a BET surface area of 369 m 2 /g. The bulk conductivity (5.72 × 10-6 S‚cm-2) of the SiO 2-carbon composite was determined by impedance measurements. The as-prepared SiO 2-carbon composite was further annealed at 500°C in air for 2 h, which led to the formation of white paramagnetic silica particles (confirmed by ESR), possessing a surface area of 111 m 2 /g. The present synthetic technique requires unsophisticated equipment and a low-cost commercial precursor, and the reaction is carried out without a solvent, surfactant, or catalyst. The mechanism for the formation of a porous SiO 2-carbon composite from the silicone grease is also presented.
Phosphorus, Sulfur, and Silicon and the Related Elements, 2006
The reaction of N,N-bis(diphenylphosphino)piperzine with elemental sulfur or selenium in toluene ... more The reaction of N,N-bis(diphenylphosphino)piperzine with elemental sulfur or selenium in toluene under refluxing conditions afforded Ph 2 P(S)N(C 4 H 8)NP(S)Ph 2 or Ph 2 P(Se)N(C 4 H 8)NP(Se)Ph 2 in a quantitative yield. The molecular structures were determined by X-ray studies.
Nanoscale Research Letters, 2006
The reaction of pentaethoxy niobate, Nb(OEt)5, at elevated temperature (800 °C) under autogenic p... more The reaction of pentaethoxy niobate, Nb(OEt)5, at elevated temperature (800 °C) under autogenic pressure provides a chemical route to niobium oxide nanorods coated with amorphous carbon. This synthetic approach yielded nanocrystalline particles of Nb2O5@C. As prepared Nb2O5@C core-shell nanorods is annealed under air at 500 °C for 3 h (removing the carbon coating) results in neat Nb2O5nanorods. According to the TEM measurements, the Nb2O5crystals exhibit particle sizes between 25 nm and 100 nm, and the Nb2O5crystals display rod-like shapes without any indication of an amorphous character. The optical band gap of the Nb2O5nanorods was determined by diffuse reflectance spectroscopy (DRS) and was found to be 3.8 eV.
Journal of Nanoparticle Research, 2007
Abstract The thermal decomposition of a reaction mixture containing W (CO) 6 and PPh 3 yielded ca... more Abstract The thermal decomposition of a reaction mixture containing W (CO) 6 and PPh 3 yielded carbon encapsulated nanocrystals of tungsten monophosphide (WP). This reaction was carried out using the RAPET technique (reaction under autogenic pressure at ...