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P. K. Palanisamy

Bio: P. K. Palanisamy is an academic researcher from Anna University. The author has contributed to research in topics: Laser & Z-scan technique. The author has an hindex of 20, co-authored 55 publications receiving 970 citations. Previous affiliations of P. K. Palanisamy include Indian Institute of Technology Madras.


Papers
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Journal ArticleDOI
TL;DR: In this article, the third-order nonlinear optical response of a triphenylmethane dye (Acid blue 7) was studied using the Z-scan technique with a continuous-wave He-Ne laser radiation at 633-nm.

126 citations

Journal ArticleDOI
17 Oct 2005-Optik
TL;DR: The third-order nonlinear optical properties of Basic Green 1 dye were measured by the Z-scan technique and measurements were carried out at different concentrations and several incident intensities as discussed by the authors.

73 citations

Journal ArticleDOI
TL;DR: Two series of new sudan dye based poly(alkyloxymethacrylate)s were synthesized with varying even number of methylene spacers The structure of the polymers was confirmed by FT-IR, 1H and 13C-NMR spectroscopy Thermal stability, glass transition and melting temperatures of polymers were investigated with thermogravimetric analysis and differential scanning calorimetry.
Abstract: Two series of new sudan dye based poly(alkyloxymethacrylate)s were synthesized with varying even number of methylene spacers The structure of the polymers was confirmed by FT-IR, 1H and 13C-NMR spectroscopy Thermal stability, glass transition and melting temperatures of the polymers were investigated with thermogravimetric analysis and differential scanning calorimetry respectively Thermal stability of the polymers decrease with the increasing chain length of the methylene chain The substituent on the azo moiety in the pendant side chain polymers has less thermal stability than the unsubstituted counterpart The optical characterization of the polymers was done by formation of the holographic grating using 5145 nm line of the Ar ion laser as source The diffraction efficiency of the grating on the polymeric film was studied by varying the length of the methylene spacer, concentration and writing beam power

70 citations

Journal ArticleDOI
TL;DR: In this article, a new approach to synthesize silver nanoparticles (AgNPs) using aqueous extract of Alpinia calcarata root as a reducing as well as stabilizing agent.

65 citations

Journal ArticleDOI
TL;DR: In this paper, a porphyrin-graphene oxide hybrid (GO-TAP) was carried out by covalently functionalizing graphene oxide (GO) with 5,10,15,20 mesotetra (4-aminophenyl) porphrin (TAP), through an amide linkage.
Abstract: The synthesis of a porphyrin-graphene oxide hybrid (GO-TAP) was carried out by covalently functionalizing graphene oxide (GO) with 5,10,15,20 mesotetra (4-aminophenyl) porphyrin (TAP) through an amide linkage. The GO-TAP hybrid has been charac- terized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and UV-visible spectroscopy. The peak intensity of the Soret band of the material was suppressed compared to neat TAP. This indicates a strong interaction between the electronic energy level of TAP and GO in the GO-TAP hybrid. The functionalization of GO with TAP significantly improved its solubility and dispersion stability in organic solvents. Scanning electron micrographs reveal that the hybrid was found to be similar to the unmodified GO but slightly more wrinkled. Transmission electron micrographs also demonstrate that GO sheet in the hybrid is more wrinkled with some dark spot due to functionalization. Atomic force microscopy results also reveal that the TAP functionalization increases the thickness of GO sheet to 2.0-3.0 nm from 1.2 to 1.8 nm. We observed improved nonlinear optical and optical limiting properties for the hybrid compared to both graphene oxide and porphyrin. GO-TAP shows fluo- rescence quenching compared with porphyrin, indicat- ing excellent electron and/or energy transfer to GO from TAP. Thermogravimetric analysis confirms that the GO-TAP hybrid has outstanding thermal stability.

60 citations


Cited by
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Journal ArticleDOI
TL;DR: The Rehybridization of the Acceptor (RICT) and Planarization ofThe Molecule (PICT) III is presented, with a comparison of the effects on yield and radiationless deactivation processes.
Abstract: 6. Rehybridization of the Acceptor (RICT) 3908 7. Planarization of the Molecule (PICT) 3909 III. Fluorescence Spectroscopy 3909 A. Solvent Effects and the Model Compounds 3909 1. Solvent Effects on the Spectra 3909 2. Steric Effects and Model Compounds 3911 3. Bandwidths 3913 4. Isoemissive Points 3914 B. Dipole Moments 3915 C. Radiative Rates and Transition Moments 3916 1. Quantum Yields and Radiationless Deactivation Processes 3916

2,924 citations

Journal ArticleDOI
TL;DR: It has been demonstrated that Ag NPs arrest the growth and multiplication of many bacteria such as Bacillus cereus, Staphylococcus aureus, Citrobacter koseri, Salmonella typhii, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia, Vibrio parahaemolyticus and fungus.
Abstract: Use of silver and silver salts is as old as human civilization but the fabrication of silver nanoparticles (Ag NPs) has only recently been recognized. They have been specifically used in agriculture and medicine as antibacterial, antifungal and antioxidants. It has been demonstrated that Ag NPs arrest the growth and multiplication of many bacteria such as Bacillus cereus, Staphylococcus aureus, Citrobacter koseri, Salmonella typhii, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia, Vibrio parahaemolyticus and fungus Candida albicans by binding Ag/Ag+ with the biomolecules present in the microbial cells. It has been suggested that Ag NPs produce reactive oxygen species and free radicals which cause apoptosis leading to cell death preventing their replication. Since Ag NPs are smaller than the microorganisms, they diffuse into cell and rupture the cell wall which has been shown from SEM and TEM images of the suspension containing nanoparticles and pathogens. It has also been shown that smaller nanoparticles are more toxic than the bigger ones. Ag NPs are also used in packaging to prevent damage of food products by pathogens. The toxicity of Ag NPs is dependent on the size, concentration, pH of the medium and exposure time to pathogens.

766 citations

Journal ArticleDOI
TL;DR: The unique suitability of molecular rotors as fluorescent viscosity sensors is shown, which cannot be separated with DMABN, while Coumarins, on the other hand, did not show Viscosity sensitivity.

347 citations

Journal ArticleDOI
TL;DR: The microorganism/plant extract and the reaction parameters used in synthesis of the AgNPs, which hold prominent impact on their size, shape, and application are described.
Abstract: Nanoparticle biosynthetic discipline is still under development and is known to have a big impact on numerous manufactures for a long time. Nowadays, biosynthesis of silver nanoparticles (AgNPs) had gained so much attention in developed countries due to development demand of environmental friendly technology for material synthesis. The use of green chemistry is environmental friendly, non-toxic, and cheap. This review focused on the recent scientific publications in the green synthesis field of AgNPs and its applications. A number of microorganisms including bacteria, fungi, yeasts, algae, and plants either intra- or extracellular have been found to be capable of synthesizing AgNPs. All scientific reports reflect the unique properties AgNPs possess that find myriad applications such as antibacterial, antifungal, antivirus, and anticancer drugs, larvicidal excellent catalytic natural action towards degradation of dyes, very good antioxidants, treatment of diabetes-related complications, and wound healing activities. The recent strategy for improving the efficacy of antibiotics is to combine them with AgNPs in order to control the microbial infections as confirmed by the damage action of AgNPs on microbial deoxyribonucleic acid. This review describes also the microorganism/plant extract and the reaction parameters used in synthesis of the AgNPs, which hold prominent impact on their size, shape, and application. Recently published information on AgNP synthesis and its applications are summarized in this review.

255 citations

Journal ArticleDOI
TL;DR: The synthesis, characterization, and application of AgNPs and AuNPs are discussed in this review and green-synthesized nanoparticles eliminate the need for a stabilizing and capping agent and show shape and size-dependent biological activities.
Abstract: This review covers general information about the eco-friendly process for the synthesis of silver nanoparticles (AgNP) and gold nanoparticles (AuNP) and focuses on mechanism of the antibacterial activity of AgNPs and the anticancer activity of AuNPs. Biomolecules in the plant extract are involved in reduction of metal ions to nanoparticle in a one-step and eco-friendly synthesis process. Natural plant extracts contain wide range of metabolites including carbohydrates, alkaloids, terpenoids, phenolic compounds, and enzymes. A variety of plant species and plant parts have been successfully extracted and utilized for AgNP and AuNP syntheses. Green-synthesized nanoparticles eliminate the need for a stabilizing and capping agent and show shape and size-dependent biological activities. Here, we describe some of the plant extracts involved in nanoparticle synthesis, characterization methods, and biological applications. Nanoparticles are important in the field of pharmaceuticals for their strong antibacterial and anticancer activity. Considering the importance and uniqueness of this concept, the synthesis, characterization, and application of AgNPs and AuNPs are discussed in this review.

255 citations