Enhancement of Optical and Thermal Properties of γ-Glycine Single Crystal: in the Presence of 2-Aminopyridine Potassium ChlorideReportar como inadecuado




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1 P. G & Research Department of Physics, Government Arts College, Tiruvannamalai, 606603

Abstract : In this research paper, an overview of polymorph γ-form glycine single crystal crystallization in the presence of 2-aminopyridine potassium chloride as an additive at an ambient temperature by slow evaporation solution growth technique SEST has been presented. FTIR and NMR studies confirm the presence of functional groups in the grown crystal. In the UV–Visible NIR optical absorption spectral studies from 200 nm to 900 nm, the observed 0% absorption with lower cutoff wave length at 240 nm and high band gap 5. 5eV enabled enhanced linear optical properties. Powder XRD study confirms crystalline nature of the grown γ-glycine crystal. The single crystal XRD study shows that the grown crystal possesses hexagonal structure and belongs to space group P31 with the cell parameters a=7. 09 Å; b=7. 09; c=5. 52 Å; α = β = 90˚; and γ = 120˚. Thermal studies have been carried out to identify the elevated thermal stability and decomposition temperature of the grown sample. Dielectric studies of as grown γ-glycine crystal exhibit low dielectric constant at higher frequencies, which is most essential parameters for nonlinear optical applications. Enhanced SHG efficiency of the grown crystal was confirmed by the Kurtz powder technique using Nd:YAG laser and found 1. 6 times greater than that of inorganic standard potassium dihydrogen phosphate. 1. Introduction. Highly polarizable conjugated system of organic molecule possesses non-centro symmetry structure and the inorganic molecule anion, linking through hydrogen bond with organic molecule cation yields strong mechanical and high thermal stability 1, 2. Molecular charge transfer induced in semiorganic complex by delocalized π electron, such that moving between electron donor and electron acceptor which are in opposite sides of the molecules 3, 4. In the base acid interaction of organic and inorganic molecules, there is a high polarizable cation derived from aromatic nitro systems, linked to the polarizable anion of inorganic molecules through hydrogen bond network yields a noncentrosymmetric structural systems and this hydrogen bonding energy between organic and inorganic molecules made the dipole moment in parallel fashion ensures the increase of second harmonic generation activity 5. The structures of 2-aminopyridine complexes have already been studied by Chao and his co-workers 6. In recent years metal organic complexes have been played reasonable attention in advancement of technology 2,7. Growth of 2-aminopyridine complex crystals is widely used in the rapid advancement in technology, such as ultra-fast phenomena, optical communication and optical storage devices , frequency doublers and optical modulators 8. Optical properties of 2-aminopyridine complexes and their suitability for optoelectronic devices have been reported 9-14. Metal organic nonlinear optical crystals possess good second harmonic generation efficiency, hence rich demand in optical storage devices, color display units and optical communication systems 7. Recent research focus is on designing of new materials capable of attaining SHG processes by strong interaction with an oscillating field of light. Amino acids with ionic salt complex crystals have been investigated and recognized as materials having good nonlinear optical properties 1,3,15-17. In this present work, synthesis and crystallization of glycine into γ-form glycine in the presence of aqueous solution 2-aminopyridine potassium chloride and their suitability for device fabrication with various enhanced optical and thermal properties are reported.

Keywords : slow evaporation single crystal NMR spectrum TGA-DTA SHG efficiency





Autor: R Srineevasan - D Sivavishnu - K Arunadevi - R Tamilselvi - J Johnson - S Kumar -

Fuente: https://hal.archives-ouvertes.fr/



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