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Parasuraman K.,Sri Muthukumaran Institute of Technology | Sakthi Murugesan K.,Presidency College at Chennai | Samuel Selvaraj R.,Presidency College at Chennai | Jerome Das S.,Loyola College | And 2 more authors.
Optik | Year: 2014

The bulk single crystal of l-arginine 4-nitrophenolate 4-nitrophenol dihydrate (LAPP), an efficient organic NLO material of size 74 mm in length, 18 mm in diameter, was grown successfully by Sankaranarayanan-Ramasamy (SR) method. Single crystal X-ray diffraction study reveals that LAPP crystallizes into monoclinic system with the space group P21. The unidirectional growth along the plane (1 1 0) was confirmed from the powder XRD pattern with the sharp peak having maximum intensity. Optical absorption spectrum shows that LAPP has highly transparent in the entire visible and IR region with a wide band gap of 3.9 eV for large photon absorption. Vickers micro hardness measurement was performed to know the mechanical strength of the crystal. Dielectric profile of LAPP at room temperature brings forth low value of dielectric loss and dielectric constant at higher frequencies. Photoluminescence study reveals that LAPP exhibit green emission in the wavelength region 538 nm. The SHG efficiency of the crystal is measured by Kurtz's powder test using Nd:YAG Laser. © 2014 Elsevier GmbH. All rights reserved. Source


Kumaresan P.,Thiru A Govindasamy Government Arts College
Optoelectronics and Advanced Materials, Rapid Communications | Year: 2010

Most irradiation studies in the hydrogen bonded ferroelectrics have been concentrated on the transient defects induced by ionising radiation such as UV light, where the defects are closely related to the optical properties. On the other hand, heavy ion beam irradiation effects have rarely been studied. Li 3+ irradiations lead to the development of a well-defined surface H peak in dye doped KDP crystals. The stability of KDP single crystal was improved by doping organic dyes. The nano-islands of dye in KDP are likely to be dissolved and enhance the non-linear optical properties of these materials. The structural, optical and non-linear optical properties of the doped crystals were analyzed with the characterization studies such as powder XRD, UV-Visible and SHG measurements respectively. The results for doped KDP crystal are compared with the results of the pure KDP crystals. Source


Narayanasamy D.,SKP Institute of Technology | Kumaresan P.,Thiru A Govindasamy Government Arts College | Ambalavanan P.,Thiru A Govindasamy Government Arts College | Anbarasan P.M.,Periyar University
Optoelectronics and Advanced Materials, Rapid Communications | Year: 2013

Amino acids (L-Glutamic acid, L-Tartaric acid) doped Triglycine sulphate (TGS) crystals are grown by solution growth technique. Slow cooling as well as slow evaporation methods were employed to grow these crystals. The concentration of dopants in the mother solution was varied from 0.1 mol% to 10 mol%. The solubility data for all dopants concentration were determined. There is variation in pH value and hence, there is habit modifications of the grown crystals were characterized. Dielectric studies reveal slight distortion of lattice parameter for the heavily doped TGS crystals. TGA-DTA studies reveal good thermal stability. The dopants increase the hardness value of the material and it also depends on the concentration of the dopants. The detailed results on the spectral parameters, habit modifications and constant values have been presented. Source


Narayanasamy D.,SKP Institute of Technology | Kumaresan P.,Thiru A Govindasamy Government Arts College | Anbarasan P.M.,Periyar University
Optoelectronics and Advanced Materials, Rapid Communications | Year: 2015

Magnetic stirrer was used to prepare saturated solution. All crystals were grown by slow evaporation process. The FTIR spectra of all grown crystals have been recorded in the range of 400 - 4000 cm–1 using Bruker FT-IR 8400 spectrophotometer by KBr pellet technique. To determine the lattice parameters, powder X-ray diffraction analysis was performed by Philips X’pert PRO X-ray diffractometer system with Cu-Kα (λ = 1.54178Å) radiation at room temperature (25˚C) with an operating voltage 40 kV and the tube current was 30 mA. In the present work, optical transmission and absorption spectra were recorded by Systronics UV-Double beam spectrometer in the wavelength range 190 to 1100 nm. © 2015, National Institute of Optoelectronics. All right reserved. Source


Kumaresan P.,Thiru A Govindasamy Government Arts College | Ambalavanan P.,Thiru A Govindasamy Government Arts College
Optoelectronics and Advanced Materials, Rapid Communications | Year: 2013

Photocatalytic hydrogen production using suspended photo catalysts were studied. TiO2 anatase in a powder form was used as photo catalyst. Our investigation aims to wards the creation of improved photo catalysts to be used in the production of hydrogen from water or aqueous solutions of organic compounds. TiO2 anatase in a powder form was used originally as photo catalyst. It was found that the photocatalytic activity depends significantly on catalyst type and its modification such as loading with various transition metal oxides. In photocatalysis, light irradiation of TiO2 powder with photon energy larger than the band-gap energy produces electrons (e-) and holes (h+) in the conduction band and the valence band, respectively. These electrons and holes are thought to have the respective abilities to reduce and oxidize chemical species adsorbed on the surface of TiO2 particles. In most photocatalytic reactions, oxidation processes are utilized for a variety of purposes, and the reduction of molecular oxygen is often used as a counter reaction. Hence, in the field of photocatalysis, most of the research interest has been focused on oxidation processes. Pure and doped thin films of TiO2 will be prepared. Nano structure in thin films of pure and doped TiO2 will be introduced by SHI irradiation. Desired modification can be achieved by tailoring it with SHI irradiation of Ag or Li with energies around 100-200MeV. We will study the structure, surface morphology and dielectric properties and resistivity and thermo dynamical properties of these films. Various schemes to accomplish visible light photo catalysis will be described along with the general synthesis issues, characterizations, and applications. One of the most exciting recent discoveries is the effect of irradiation on TiO2 were improve the optical reactivity of TiO2 in the visible region. Source

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